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1
Modeling the kinetics of grain-boundary-nucleated recrystallization processes after cold deformation
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Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
S. P. Chen , S. Van Der Zwaag , I. Todd
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2002
Metallurgical and Materials Transactions A
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A physical model to predict the recrystallization kinetics of single-phase polycrystalline metals, based on a single grain representation of deformed microstructure (characterized by a mean subgrain size and mean misorientation of subgrain boundaries), is presented. The model takes into account the grain geometry, the position, and the density of the nucleation sites. The selected geometry is a regular tetrakaidecahedron, combining topological features of a random Voronoi-distribution characteristic for polycrystalline material with the advantages of a single grain calculation. The model employs empirically determined relationships from existing literature to describe the deformed microstructure and, in so doing, facilitates the prediction of the recrystallization behavior when only the deformation strain and the recrystallization temperature are known. The boundary mobility and the driving force, as well as the nucleation density, are related to the true plastic strain of deformation through the microstructure. The model also describes the effects of concurrent recovery on the overall recrystallization kinetics.
DOI : 10.1007/s11661-002-0115-4
Anahtar Kelimeler : Recrystallization, Material Transaction, Nucleation Site, Deformation Strain, Driving Pressure
ISSN: 1073-5623 1543-1940
Sayı: 3
Cilt: 33
Sayfa: 529-537
2
The tensile deformation behavior of AA 3004 aluminum alloy
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Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
D. PARK , J. G. MORRIS
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
1994
Metallurgical and Materials Transactions A
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AA 3004 aluminum alloy for can body stock exhibits interesting serrated flow in the stress-strain curves at room temperature. The serrated-flow phenomena are associated with dy-namic strain aging and yield a negative strain-rate dependence of the flow stress. The occurrence of the serrated flow resulting from a negative dependence of the flow stress is well known to limit the formability of many alloys. In order to obtain an in-depth understanding of the serrated flow of the alloy, the characteristics of the serrations were examined as well as the dependence of flow stress on the strain rate and deformation temperature. A description of the effect of deformation temperature and strain-rate sensitivity on the mechanical behavior is discussed.
DOI : 10.1007/bf02647981
Anahtar Kelimeler : Aluminum Alloy, Material Transaction, Flow Stress, Deformation Temperature, Dynamic Strain Aging
ISSN: 1073-5623 1543-1940
Sayı: 2
Cilt: 25
Sayfa: 357-364
3
Distortion in a 7xxx Aluminum Alloy during Liquid Phase Sintering
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Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
X. N. Yuan , S. H. Huo , G. B. Schaffer , M. Qian
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2013
Metallurgical and Materials Transactions A
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The distortion in a sintered 7xxx aluminum alloy, Al-7Zn-2.5Mg-1Cu (wt. pct), has been investigated by sintering three rectangular bars in each batch at 893 K (620 °C) for 0 to 40 minutes in nitrogen, followed by air or furnace cooling. They were placed parallel to each other, equally spaced apart at 2 mm, with their long axes being perpendicular to the incoming nitrogen flow. Pore evolution in each sample during isothermal sintering was examined metallographically. The compositional changes across sample mid-cross section and surface layers were analyzed using energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy depth profiling, respectively. The two outer samples bent toward the middle one, while the middle sample was essentially distortion free after sintering. The distortion in the outer samples was a result of differential shrinkage between their outer and inner surfaces during isothermal sintering. The porous outer surface showed an enrichment of oxygen around the large pores as well as lower magnesium and zinc contents than the interior and inner surface of the same sample, while the inner surface was distinguished by the presence of AlN. The differential shrinkage was caused by different oxygen contents in local sintering atmosphere and unbalanced loss of magnesium and zinc between the outer and inner surfaces.
DOI : 10.1007/s11661-013-2009-z
Anahtar Kelimeler : Isothermal Hold, Sintered Density, Furnace Cool, Outer Sample, Outer Surface Layer
ISSN: 1073-5623 1543-1940
Sayı: 2
Cilt: 45
Sayfa: 1010-1018
4
Phase equilibria and transformations in a Ti-Zr-Si system
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Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
N. H. Salpadoru , H. M. Flower
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
1995
Metallurgical and Materials Transactions A
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The phase equilibria in the titanium-zirconium rich region of the ternary Ti-Zr-Si system have been studied in the temperature range from 1473 to 1323 K, together with microstructures pres-ent in the as-cast state. DTA, microscopy, X-ray diffraction (XRD), and chemical analysis by X-ray energy-dispersive spectroscopy have been employed. Whereas Ti5Si3 nucleates hetero-geneously and grows rapidly in titanium matrices, Ti3Si exhibits very slow precipitation kinetics. It also is displaced by (Ti, Zr)5Si3 and a ternary silicide in ternary and more complex systems, explaining its absence in commercial alloys. Zirconium exhibits substantial solid solubility in Ti5Si3in ternary alloys, while Ti exhibits only limited solubility in Zr2Si, Zr3Si, and Zr5Si3. Additionally, a new silicide of general formula (Ti, Zr)2Si is formed in ternary alloys with a Ti:Zr ratio ranging from 2.26 to 0.68. Isothermal sections for the Ti-Zr-Si system are presented for temperatures of 1473 and 1323 K.
DOI : 10.1007/bf02664663
Anahtar Kelimeler : Material Transaction, Ternary Alloy, Binary Phase Diagram, Backscatter Electron Image, Silicide Phase
ISSN: 1073-5623 1543-1940
Sayı: 2
Cilt: 26
Sayfa: 243-257
5
Mn3O4 and (ZnFe)OOH Composites for Supercapacitors with High Active Mass
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Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
R. Poon , W. Liang , I. Zhitomirsky
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2019
Metallurgical and Materials Transactions A
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A new colloidal method has been developed for the fabrication of Mn3O4-carbon nanotube (CNT) composites for positive electrodes of supercapacitors and areal capacitance of 5.04 F cm−2 has been achieved. In this method, chemical precipitation of Mn3O4 was performed in the presence of carbon nanotubes, dispersed using a tolonium chloride dye. An electrostatic heterocoagulation mechanism has been developed, which allowed for enhanced mixing of Mn3O4 and CNT, and resulted in enhanced electrochemical performance at high active mass of 36 mg cm−2. Testing results revealed changes in microstructure and oxidation state of Mn during cycling, which allowed for enhanced capacitance. In order to utilize the high capacitance of the positive Mn3O4-CNT electrodes in supercapacitor devices, advanced negative electrodes have been developed. (ZnFe)OOH-polypyrrole coated CNT electrodes with enhanced areal capacitance in a negative potential window have been fabricated. Asymmetric devices showed promising performance in a voltage window of 1.6 V.
DOI : 10.1007/s11661-019-05561-x
ISSN: 1073-5623 1543-1940
Sayı: 2
Cilt: 51
Sayfa: 855-862
6
Warm Formability of 0.2 Pct C-1.5 Pct Si-5 Pct Mn Transformation-Induced Plasticity-Aided Steel
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Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Koh-ichi Sugimoto , Shin-nosuke Hidaka , Hikaru Tanino , Junya Kobayashi
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2017
Metallurgical and Materials Transactions A
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The warm stretch formability and flangeability of 0.2 pct C-1.5 pct Si-5 pct Mn transformation-induced plasticity-aided sheet steel with annealed martensite matrix were investigated for automotive applications. Both formabilities were enhanced by warm forming at peak temperatures of 423 K to 573 K and 423 K to 523 K (150 °C to 300 °C and 150 °C to 250 °C), respectively. The superior warm formabilities were mainly due to the stabilization of a large amount of retained austenite by warm forming and the consequent considerably suppressed void growth at the interface between the matrix and transformed martensite, despite there being large hole punching damage for the stretch flangeability. High peak temperatures for stretch formability and flangeability were associated with apparently increased M S of the retained austenite resulting from the increased mean normal stress on stretch forming and hole expansion.
DOI : 10.1007/s11661-017-4046-5
Anahtar Kelimeler : Austenite, Martensite, Intercritical Annealing, Hole Expansion, Hole Expansion Ratio
ISSN: 1073-5623 1543-1940
Sayı: 5
Cilt: 48
Sayfa: 2237-2246
7
Precipitate Size in the Superalloy IN738LC During Compression Creep
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Arun Altincekic , Ercan Balikci
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2013
Metallurgical and Materials Transactions A
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Superalloys are high-temperature materials that are used widely in many industries especially in several engine components in gas turbines. One of the many nickel-base superalloys is IN738LC, which possesses a good high-temperature strength and hot corrosion resistance. It is employed mainly in nozzle guide vanes and blades of land-based turbines. The strengthening is provided mainly by coherent γ′ precipitates. The current research is undertaken to determine precipitate size in IN738LC specimens aged under compressive stress. To observe the influence of magnitude of stress, a constant compressive load is applied to conical specimens that are aged in an inert atmosphere for various times [24, 192, 480, and 960 hours at 1223 K (950 °C) and 12, 24, 192, and 480 hours at 1323 K (1050 °C)]. Thus, the study of microstructural changes due to various stress levels becomes possible with a single specimen in the same experimental condition. A single-size distribution of precipitates has been observed except for the 192-hour and 480-hour experiments at 1323 K (1050 °C). The results indicate that the average precipitate size is directly proportional to the temperature but inversely proportional to the applied stress, although in some specimens, maximum size is observed at medium-stress levels. Strain becomes effective at most severely crept specimen by causing a merging of precipitates. Raft degeneration is also observed in this specimen. The growth exponent is found to vary with stress and temperature between 2.97 and 3.78.
DOI : 10.1007/s11661-013-1618-x
Anahtar Kelimeler : Aging Time, Creep Deformation, Fine Precipitate, Precipitate Size, Growth Exponent
ISSN: 1073-5623 1543-1940
Sayı: 6
Cilt: 44
Sayfa: 2487-2498
8
Effect of Extrusion Parameters on Texture and Microstructure Evolution of Extruded Mg-1 pctMn and Mg-1 pctMn-Sr Alloys
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Hemant Borkar , Mihriban Pekguleryuz
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2014
Metallurgical and Materials Transactions A
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Three Mg alloys Mg-1 pctMn (M1), Mg-1 pctMn-1.3 pctSr, and Mg-1 pctMn-2.1 pctSr were subjected to two different extrusion temperatures and two different extrusion speeds in lab-scale extrusion. The extrusion temperatures of 573 K and 673 K (300 °C and 400 °C) and two ram speeds of 4 and 8 mm/s were used at constant extrusion ratio of 7. M1 exhibited strong basal texture after extrusion at 673 K (400 °C) at higher speed. At 573 K (300 °C), recrystallization in all alloys takes place completely or partially by continuous dynamic recrystallization mechanism, while particle stimulated nucleation (PSN) occurs in all M1-Sr alloys at both extrusion temperatures and speeds. At 673 K (400 °C), grain boundary bulging is the only recrystallization mechanism in alloy M1, while it occurs in combination with PSN in M1-Sr alloys. The effect of texture weakening by PSN is more significant in M1-Sr alloys extruded at 573 K (400 °C). The plant extrusion trials were carried out on Mg-1 pctMn, Mg-1 pctMn-0.3 pctSr, and Mg-1 pctMn-2.1 pctSr at 623 K (350 °C) with different speeds than in lab-scale extrusion. M1 alloy exhibited strong basal texture at both speeds, while Sr additions of 0.3 and 2.1 pct promoted similar amount of texture weakening.
DOI : 10.1007/s11661-014-2636-z
Anahtar Kelimeler : Extrusion Ratio, Extrusion Temperature, Texture Weaken, Extrusion Speed, Recrystallization Mechanism
ISSN: 1073-5623 1543-1940
Sayı: 1
Cilt: 46
Sayfa: 488-495
9
Effects of simultaneous displacive and ionizing radiations and of electric field on radiation damage in ionic crystals
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Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Chiken Kinoshita , Syo Matsumura , Kazuhiro Yasuda , Mikio Shimada
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2004
Metallurgical and Materials Transactions A
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We summarize our recent progress on the formation process of radiation-induced defects, their stability, and cation- and anion-disordering in ionic crystals, such as magnesium aluminate spinel and alpha alumina, under simultaneous displacive and ionizing radiations or under electric field. In those crystals, suppression of dislocation loop formation is observed under simultaneous ionizing and displacive radiations. Cation and anion disordering are also detected through newly developed analytica electron microscopy. Furthermore, the electric field suppresses the formation of dislocation loops and enhances their growth in thinner specimens of ionic crystals. Those results are discussed in terms of the instability of defect clusters under electronic excitation and displacements of structure vacancies and of the interaction between charged defects and electric fields.
DOI : 10.1007/s11661-006-0205-9
Anahtar Kelimeler : Material Transaction, Dislocation Loop, Electron Irradiation, Defect Cluster, Loop Formation
ISSN: 1073-5623 1543-1940
Sayı: 8
Cilt: 35
Sayfa: 2257-2266
10
Zn Diffusion and α-Fe(Zn) Layer Growth During Annealing of Zn-Coated B Steel
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Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Vit Janik , Yongjun Lan , Peter Beentjes , David Norman , Guido Hensen , Seetharaman Sridhar
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2015
Metallurgical and Materials Transactions A
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Direct hot press forming of Zn-coated 22MnB5 steels is impeded by micro-cracks that occur in the substrate due to the presence of Zn during the forming process. A study was therefore undertaken to quantify concentration of Zn across the α-Fe(Zn) coating and on grain boundaries in the α-Fe(Zn) layer and the underlying γ-Fe(Zn) substrate after isothermal annealing of Zn-coated 22MnB5 at 1173 K (900 °C) and to link the Zn distribution to the amount and type of micro-cracks observed in deformed samples. Finite difference model was developed to describe Zn diffusion and the growth of the α-Fe(Zn) layer. The penetration of Zn into the γ-Fe(Zn) substrate after 600 seconds annealing at 1173 K (900 °C) through bulk diffusion is estimated to be 3 μm, and the diffusion depth of Zn on the γ-Fe(Zn) grain boundaries is estimated to be 6 μm, which is significantly shorter than the maximum length (15 to 50 μm) of the micro-cracks formed in the severely stressed conditions, indicating that the Zn diffusion into the γ-Fe(Zn) from the α-Fe(Zn) during annealing is not correlated to the depth of micro-cracks. On the other hand, the maximum amount of Zn present in α-Fe(Zn) layer decreases with annealing time as the layer grows and Zn oxidizes, and the amount of Zn-enriched areas inside the α-Fe(Zn) layer is reduced leading to reduced length of cracking. Solid-Metal-Induced Embrittlement mechanism is proposed to explain the benefit of extended annealing on reduced depth of micro-crack penetration into the γ-Fe(Zn) substrate.
DOI : 10.1007/s11661-015-3203-y
Anahtar Kelimeler : Coating Layer, Boundary Diffusion, Effective Diffusion Coefficient, Increase Annealing Time, Finite Difference Method
ISSN: 1073-5623 1543-1940
Sayı: 1
Cilt: 47
Sayfa: 400-411
11
Wetting of the (0001) α-Al2O3 Sapphire Surface by Molten Aluminum: Effect of Surface Roughness
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Joaquin Aguilar-Santillan
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2010
Metallurgical and Materials Transactions A
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The wetting of molten aluminum on the “c”-plane (0001) of single-crystal α-Al2O3 (sapphire) was studied by the sessile drop technique from 800 °C (1073 K) to 1200 °C (1473 K). Systematically increasing the (0001) surface roughness by SiC abrasion increased the wetting contact angle, resulting in reduced wetting. The surface roughness factor R originally defined by Wenzel, was determined as a function of the abrasion, temperature, and time. The wetting decreases as the surface roughness increases. Rough surfaces also create time and temperature effects on wetting, changing those for a smoothly polished surface. The existence of a high-temperature surface structural transition for (0001) of α-Al2O3, which has been previously suggested, was confirmed. Increased roughness R accents the effect of the surface structural transition, increasing the wetting contact angle changes during the transition.
DOI : 10.1007/s11661-009-0144-3
Anahtar Kelimeler : Contact Angle, Sapphire, Sessile Drop, Molten Aluminum, Roughness Factor
ISSN: 1073-5623 1543-1940
Sayı: 3
Cilt: 41
Sayfa: 676-685
12
Quantitative analysis of texture evolution in cold-rolled, continuous-cast AA 5xxx-series aluminum alloys
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
W. C. Liu , J. G. Morris
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2004
Metallurgical and Materials Transactions A
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The texture evolution of continuous-cast AA 5xxx-series aluminum alloys during cold rolling was investigated by X-ray diffraction. Texture volume fractions were calculated by an improved integration method. The results show that the relationship between the texture volume fractions and true strain can be quantified by mathematical formulae. The effect of alloy composition as well as initial microstructure and texture on rolling-texture evolution can be evaluated by the k i and n i values in the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation. The k i value reflects the rate of formation or disappearance of the texture components. The high-Fe AA 5754 aluminum alloy exhibits the lowest formation rate of the β fiber among the AA 5005, 5052, 5754, 5182, and high-Fe 5754 aluminum alloys.
DOI : 10.1007/s11661-004-0127-3
Anahtar Kelimeler : Aluminum Alloy, Material Transaction, Texture Component, Texture Evolution, Orientation Distribution Function
ISSN: 1073-5623 1543-1940
Sayı: 1
Cilt: 35
Sayfa: 265-277
13
Comparison of three different techniques for measuring the residual stresses in an electron beam-welded plate of WASPALOY
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
H. J. Stone , P. J. Withers , S. M. Roberts , R. C. Reed , T. M. Holden
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
1999
Metallurgical and Materials Transactions A
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The longitudinal, transverse, and through-thickness (short-transverse) residual stresses in an electron beam-welded plate of WASPALOY, a high-strength nickel-based superalloy, have been characterized using neutron diffraction, X-ray diffraction, and a hole-drilling method. Where possible, the results from the different techniques, and the associated uncertainties, have been compared. For the neutron measurements, the γ/γ′ {111} peak was used for the determination of lattice strains. The X-ray measurements were carried out using Fe K α radiation, the sin2 ψ technique, and the {311} γ/γ′ composite peak. The Matthar-Soete method was used for the incremental hole-drilling measurements. Unfortunately, due to texture effects, it was not possible to detect the residual stresses within the weld metal by the diffraction-based methods. For the estimation of residual stresses, plane-specific values of the Young’s modulus and Poisson’s ratio were determined from tensile testpieces using in situ neutron diffractometry. When these data are used, it is found that the neutron, X-ray, and hole-drilling residual stress data are mutually consistent, although the absolute certainties vary with the method employed. The results indicate that, next to the weld, the longitudinal residual stresses approach 1000 MPa and are typically far greater (up to 5 times) than those in the transverse and through-thickness directions. Measurements of the longitudinal strain with distance along the welding direction indicate that the stress state reaches a steady state over the central portion of the plate; for this reason, the majority of the diffraction measurements have been made in the plane perpendicular to the weld at the center of the plate. A simple analysis of the thermal cycles and the extent of plastic deformation induced in the specimen is presented. The plastic “upset zone” has a size which is at least 3 times greater than the cross-sectional area of the weld metal; this suggests that, for accurate analysis of weld-induced distortion, attention should be paid to the evolution of residual stresses in the heat-affected zone as well as the fusion zone.
DOI : 10.1007/s11661-999-0178-6
Anahtar Kelimeler : Residual Stress, Material Transaction, Weld Metal, Neutron Diffraction, Residual Stress Measurement
ISSN: 1073-5623 1543-1940
Sayı: 7
Cilt: 30
Sayfa: 1797-1808
14
Application of the Eyring Equation in the Evaluation of Semi-Solid Forming-Induced Si Particle Refinement in the Hypereutectic Al-Si Alloys
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Yasuyoshi Fukui , Daisaku Nara , Kazuyo Fushimi , Noriyoshi Kumazawa
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2015
Metallurgical and Materials Transactions A
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On the basis of Eyring’s theory of absolute reaction rate, an approach to modeling Si particle refinement acceleration in the semi-solid forming of a hypereutectic Al-Si alloy has been developed. The acceleration variable data used in the present analysis were obtained from a semi-solid compression test using Al-25 mass pct Si alloy cylindrical specimens with a diameter of 15 mm and a height of 15 mm; the test conditions comprised a combination of compression displacements ∆h = 5, 10, and 12 mm; compression rates v = 5, 25, and 125 mm/min; and test temperatures T = 853 K and 863 K (580 °C and 590 °C). The coarse primary Si particle refinement depends on a complex interaction among variables, such as compression displacement, compression rate, and test temperature. The performance of Si particle refinement degraded under higher temperature, slower strain rates, and slower shear rates. The results of the Si particle size are suitably summarized by the Eyring equation as a function of the temperature and the shear rate. The baseline Si particle size and the baseline temperature of Si particle refinement, i.e., the reference temperature, were G N = 0.27 mm and T N = 866.4 K (593.4 °C), respectively. The calculated results using this equation correlated well with the observed results. An acceleration factor of Si particle refinement was successfully derived on the basis of this equation and indicated that operating at a higher shear rate and a temperature just above the melting point of eutectic Al-Si alloy are the optimum conditions for refining Si particles.
DOI : 10.1007/s11661-015-3143-6
Anahtar Kelimeler : Shear Rate, Compression Rate, Baseline Temperature, Hypereutectic Alloy, Eyring Equation
ISSN: 1073-5623 1543-1940
Sayı: 12
Cilt: 46
Sayfa: 5856-5863
15
Dendrite growth processes of silicon and germanium from highly undercooled melts
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Tomotsugu Aoyama , Yuzuru Takamura , Kazuhiko Kuribayashi
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
1999
Metallurgical and Materials Transactions A
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The crystal growth behavior of a semiconductor from a very highly undercooled melt is expected to be different from that of a metal. In the present experiment, highly pure undoped Si and Ge were undercooled by an electromagnetic levitation method, and their crystal growth velocities (V) were measured as a function of undercooling (ΔT). The value of V increased with ΔT, and V=26 m/s was observed at ΔT=260 K for Si. This result corresponds well with the predicted value based on the dendrite growth theory. The growth behaviors of Si and Ge were found to be thermally controlled in the measured range of undercooling. The microstructures of samples solidified from undercooled liquid were investigated, and the amount of dendrites immediately after recalescence increased with undercooling. The dendrite growth was also observed by a high-speed camera.
DOI : 10.1007/s11661-999-0282-7
Anahtar Kelimeler : Material Transaction, Growth Velocity, Dendrite Growth, Chill Plate, Video Tape Recorder
ISSN: 1073-5623 1543-1940
Sayı: 5
Cilt: 30
Sayfa: 1333-1339
16
Microstructure of the Nickel-Base Superalloy CMSX-4 Fabricated by Selective Electron Beam Melting
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Markus Ramsperger , Robert F. Singer , Carolin Körner
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2016
Metallurgical and Materials Transactions A
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Powder bed-based additive manufacturing (AM) processes are characterized by very high-temperature gradients and solidification rates. These conditions lead to microstructures orders of magnitude smaller than in conventional casting processes. Especially in the field of high performance alloys, like nickel-base superalloys, this opens new opportunities for homogenization and alloy development. Nevertheless, the high susceptibility to cracking of precipitation-hardenable superalloys is a challenge for AM. In this study, electron beam-based AM is used to fabricate samples from gas-atomized pre-alloyed CMSX-4 powder. The influence of the processing strategy on crack formation is investigated. The samples are characterized by optical and SEM microscopy and analyzed by microprobe analysis. Differential scanning calorimetry is used to demonstrate the effect of the fine microstructure on characteristic temperatures. In addition, in situ heat treatment effects are investigated.
DOI : 10.1007/s11661-015-3300-y
Anahtar Kelimeler : Additive Manufacturing, Crack Density, Interdendritic Region, Dendrite Core, Liquid Metal Cool
ISSN: 1073-5623 1543-1940
Sayı: 3
Cilt: 47
Sayfa: 1469-1480
17
The effects on fracture toughness of ductile-phase composition and morphology in Nb-Cr-Ti and Nb-Siin situ composites
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
D. L. Davidson , K. S. Chan , D. L. Anton
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
1996
Metallurgical and Materials Transactions A
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Niobium-chromium alloys, both single and two phase, were alloyed with titanium in order to enhance fracture toughness and fatigue crack growth resistance. The selection of titanium as an alloying element and the relationship of electronic bonding to toughness are examined. The results indicated that toughness increased with a decreasing number of D +s electrons. Titanium was found to increase the toughness of solid-solution Nb-Cr alloys from ≈8 to 87 MPa√m, while for the twophase “insitu composites,” toughness was increased from ≈5 to 20 MPa√m, although this is less than expected. Fracture toughness of the composites correlated nonlinearly with the volume fraction of the phases. The evidence suggests that the toughness of the composites is decreased due to fracture of the intermetallic particles and constraint on matrix deformation imposed by the intermetallic. Fracture characteristics of the Nb-Cr-Ti materials are compared to those of Nb-Cr and Nb-Si materials.
DOI : 10.1007/bf02663850
Anahtar Kelimeler : Fracture Toughness, Material Transaction, Fatigue Crack Growth, Compact Tension, Material Research Society
ISSN: 1073-5623 1543-1940
Sayı: 10
Cilt: 27
Sayfa: 3007-3018
18
Static strain aging phenomena in cold-rolled dual-phase steels
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
T. Waterschoot , B. C. De Cooman , A. K. De , S. Vandeputte
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2003
Metallurgical and Materials Transactions A
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The effect of low-temperature aging, with aging temperatures up to 170 °C, on a cold-rolled CMn-CrMo dual-phase (DP) ferrite-martensite steel was investigated. This material was processed using three different intercritical annealing treatments, leading to DP structures with different microstructures and properties. It has been found that both the aging in the ferrite phase and the tempering in the martensite play an important role in the mechanical behavior of the material with regard to the strain aging phenomena. The yield stress increase accompanying the aging phenomenon revealed three separate aging stages. In the present study, those stages were determined to be the result of the pinning of dislocations in the ferrite, the C-cluster formation, or low-temperature carbide precipitation in the ferrite and the volume contraction of the martensite due to formation of low-temperature carbides, leading to the relief of residual stresses in the ferrite. In the absence of a clear yield point, a new method is proposed to measure the increase in yield stress due to aging only.
DOI : 10.1007/s11661-003-0113-1
Anahtar Kelimeler : Ferrite, Martensite, Material Transaction, Interstitial Carbon, Yield Stress Increase
ISSN: 1073-5623 1543-1940
Sayı: 3
Cilt: 34
Sayfa: 781-791
19
Modeling the flow behavior of a medium carbon microalloyed steel under hot working conditions
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
J. M. Cabrera , A. Al Omar , J. M. Prado , J. J. Jonas
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
1997
Metallurgical and Materials Transactions A
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The constitutive equations for the flow behavior of a commercial 0.34 pct C-1.5 pct Mn-0.7 pct Si-0.083 pct V-0.018 pct Ti microalloyed steel were determined. For this purpose, uniaxial hot compression tests were carried out over a wide range of strain rates (10−4 to 10 s−1) and temperatures (1123 to 1423 K). In combination with models developed in the literature, the experimental results permit the flow stress of the present steel to be predicted within ± 5 pct. It is shown that the classical constitutive equations must be modified to take the grain size into account, particularly when the latter is below 30 µm.
DOI : 10.1007/s11661-997-0181-8
Anahtar Kelimeler : Material Transaction, Internal Stress, Peak Stress, Dynamic Recrystallization, Dynamic Recovery
ISSN: 1073-5623 1543-1940
Sayı: 11
Cilt: 28
Sayfa: 2233-2244
20
Cyclic deformation behavior and microstructures of hydrided ZIRCALOY-4 under biaxial loading
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
L. Xiao , Y. Umakoshi , J. Sun
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2001
Metallurgical and Materials Transactions A
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Biaxial fatigue behavior of hydrided ZIRCALOY-4 (Zr-4) in the as-cold-worked (CW) and recrystallized (RZ) conditions under in-phase (IP) and out-of-phase (OP) cyclic loading was investigated. The CW Zr-4 showed cyclic softening followed by a saturation stage during biaxial cyclic loading. Additional cyclic softening was displayed in CW Zr-4 under OP loading with the phase lag of 30 and 60 deg. The additional softening level decreased as the phase lag increased. On the other hand, RZ Zr-4 showed cyclic hardening followed by a saturation stage, and additional cyclic hardening was obtained under OP loading. The additional hardening arose as the phase lag increased. Observation of the fracture surface showed that the biaxial fatigue failure of the CW Zr-4 under OP loading was controlled by crack initiation and propagation through the hydrides, while the nucleation and coalescence of microvoids were dominant in the failure of CW Zr-4 under IP loading and RZ Zr-4 under both IP and OP loading. The typical deformation substructure in CW Zr-4 specimens was composed of dislocation tangles together with parallel dislocation lines under IP and OP loading. Whereas the parallel dislocation lines were formed by prismatic slip for RZ Zr-4 under IP loading and OP loading with the lower phase lag, they developed into dislocation networks, loops, and debris as the phase lag increased under OP loading. The additional cyclic softening for CW Zr-4 was due to the relief of the anisotropic hardening mechanisms when the loading mode changed from IP to OP. The additional cyclic hardening of RZ Zr-4 under OP loading is attributed to an increase in the interaction between the primary dislocations and other dislocations from different slip systems.
DOI : 10.1007/s11661-001-1034-5
Anahtar Kelimeler : Hydride, Material Transaction, Cyclic Hardening, Prismatic Slip, Cyclic Softening
ISSN: 1073-5623 1543-1940
Sayı: 11
Cilt: 32
Sayfa: 2841-2850
21
The Correlation Between Grain Orientation Evolution and Stress Rupture Properties of Waspaloy
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Mai-cang Zhang , Qi Zhang , Kang Wei
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2018
Metallurgical and Materials Transactions A
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The grain orientation evolution of Waspaloy with different initial grain sizes under the same stress rupture tests were systematically investigated by electron back-scattered diffraction (EBSD). Correlation between the grain orientation evolution and the changes of stress rupture properties were also studied. The results show that the specimens with different initial grain sizes present different grain orientation evolution behaviors during the constant stress loading process, and the stress rupture lives of alloy are closely related to the orientation changes. Specimen with large initial grain size generally exhibits a small lattice rotation, in the [101] orientation and consequently, a long stress rupture life. On the converse, the fine grain specimen exhibits significantly shorter life with much more [111] orientation, since the lattice is obviously rotated and the deformation has little coordination. Further analysis shows that initial grain size affects the misorientation distribution in the grain, which has a significant influence on the stress rupture life. The lower the misorientation angle and the higher the proportion of the low-angle misorientation is, the longer the rupture time it exhibits.
DOI : 10.1007/s11661-018-4923-6
ISSN: 1073-5623 1543-1940
Sayı: 12
Cilt: 49
Sayfa: 6063-6074
22
Microstructural Characterization of Internal Welding Defects and Their Effect on the Tensile Behavior of FSW Joints of AA2198 Al-Cu-Li Alloy
Dergi Makalesi

Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Thomas Le Jolu , Thilo F. Morgeneyer , Anne Denquin , Mohamed Sennour , Anne Laurent , Jacques Besson , Anne-Françoise Gourgues-Lorenzon
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2014
Metallurgical and Materials Transactions A
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Internal features and defects such as joint line remnant, kissing bond, and those induced by an initial gap between the two parent sheets were investigated in AA2198-T851 friction stir welded joints. They were compared with the parent material and to defect-free welds obtained using a seamless sheet. The cross-weld tensile strength was reduced by the defects by less than 6 pct. The fracture elongation was not significantly affected in view of experimental scatter. Fracture location, however, changed from the thermomechanically affected zone (retreating side) to the defect in the weld nugget for the welds bearing a kissing bond and for some of the gap welds. The kissing bond was shown by EBSD to be an intergranular feature; it fractured under a normal engineering stress close to 260 MPa during an in situ SEM tensile test. Synchrotron tomography after interrupted tensile testing confirmed opening of the kissing bond. For an initial gap of 23 pct of the sheet thickness, intergranular fracture of copper-enriched or oxide-bearing grain boundaries close to the nugget root was evidenced. The stress and strain state of cross-weld specimens loaded under uniaxial tension was assessed using a 3D finite element, multi-material model, determined on the basis of experimental data obtained on the same specimens using digital image correlation.
DOI : 10.1007/s11661-014-2537-1
Anahtar Kelimeler : Welding, Friction Stir Welding, Digital Image Correlation, Friction Stir Welding, Constitutive Parameter
ISSN: 1073-5623 1543-1940
Sayı: 12
Cilt: 45
Sayfa: 5531-5544
23
Diffusion coefficients for modeling the heat treatment of Ti-6Al-4V
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
S. L. Semiatin , T. M. Brown , T. A. Goff , P. N. Fagin , R. E. Turner , J. M. Murry , D. R. Barker , J. D. Miller , F. Zhang
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2004
Metallurgical and Materials Transactions A
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Values of the diffusivity of aluminum and vanadium that can be used for engineering-oriented calculations of the diffusional growth of primary alpha during the heat treatment of Ti-6Al-4V were established using diffusion couples consisting of various Ti-Al-V alloys. After taking compositional influences into account using thermodynamic correction factors, the pertinent diffusivities in the ternary alloy were found to be approximately 80 pct of those previously estimated from tracer or impurity (binary) diffusion experiments.
DOI : 10.1007/s11661-004-0250-1
Anahtar Kelimeler : Vanadium, Material Transaction, Diffusion Couple, Beta Phase, Final Heat Treatment
ISSN: 1073-5623 1543-1940
Sayı: 9
Cilt: 35
Sayfa: 3015-3018
24
A Fast-Acting Method for Simulating Precipitation During Heat Treatment of Superalloy 718
Dergi Makalesi

Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
S. L. Semiatin , J. S. Tiley , F. Zhang , T. M. Smith , R. Y. Zhang , H. B. Dong , P. Gadaud , J. Cormier
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2021
Metallurgical and Materials Transactions A
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A fast-acting, mean-field method for simulating precipitation of the γ′′ and γ′ phases during aging of superalloy 718 following super-delta-solvus solution treatment was formulated and validated using observations in the literature. The approach assumed classical (homogeneous) nucleation and diffusion-controlled growth (N&G) of disk/ellipsoidal-shaped-γ′′ and spherical-γ′ particles. For the γ′′ precipitates in particular, the evolution equations for both nucleation and growth incorporated corrections for the non-spherical shape, assuming a fixed aspect ratio. In addition, special attention was paid to the choice of input material properties for simulations. These parameters included the bulk free energies of transformation, particle-matrix (misfit) elastic strain energy (for γ′′), effective diffusivities, and the γ′′–γ and γ′–γ interface energies. The applicability of the diffusivities and interface energies chosen for the N&G simulations was established by their consistency in replicating previously measured rate constants for the diffusion-controlled coarsening of both γ′′ and γ′. The N&G formulation was discretized to obtain numerical (spreadsheet) solutions via the Kampmann–Wagner approach. Simulation results for the temporal evolution of volume fraction and average size of the precipitates showed good agreement with experimental measurements. The sensitivity of model predictions to various input parameters was also quantified.
DOI : 10.1007/s11661-020-06092-6
ISSN: 1073-5623 1543-1940
Sayı: 2
Cilt: 52
Sayfa: 483-499
25
Modeling of spray-formed plates using an X-Y moving substrate
Dergi Makalesi

Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Y.J Lin , E. J. Lavernia , J. E. Bobrow , W. Feng
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2001
Metallurgical and Materials Transactions A
Yayıncı Web Sitesi
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A mathematical model, incorporating the thermal component of sticking efficiency (SE t) into the calculation of shape evolution, is formulated to predict the evolution and final geometry of plates. The plates are spray formed using a moving substrate displaced in a two-dimensional (i.e., X-Y) plane. By using this model, the effects of the substrate movement parameters, such as the acceleration, time required to complete a stroke in the reciprocal movement direction (X-axis), and the velocity in the uniform movement direction (Y-axis), on the shapes of the plates are investigated. The processing parameters are evaluated by minimizing the values of the mean-squared (MS) surface roughness. On the basis of the evaluation, the optimal combinations of processing parameters are found.
DOI : 10.1007/s11661-001-0099-5
Anahtar Kelimeler : Material Transaction, Critical Velocity, Liquid Fraction, Spray Distance, Final Geometry
ISSN: 1073-5623 1543-1940
Sayı: 3
Cilt: 32
Sayfa: 831-840
26
Microstructural Evolution in an Fe-10Ni-0.1C Steel During Heat Treatment and High Strain-Rate Deformation
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
I. Harding , I. Mouton , B. Gault , K. S. Kumar
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2020
Metallurgical and Materials Transactions A
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The fine structure in an Fe-10Ni-1.0Mo-0.6Mn-0.6Cr-0.08V-0.1C (wt pct) steel in a multi-step heat-treated condition called ‘QLT’ is understood by tracking its evolution in each step using transmission electron microscopy (TEM) and atom probe tomography; further, the consequence of high strain-rate deformation on the site-specific change in the QLT microstructure is examined by microdiffraction and energy dispersive spectroscopy in the TEM. The QLT treatment results in two generations of austenite (arising from the L- and the T-step) with differing Ni content. The primary focus of this study is on the thermal and mechanical stability of the precipitated austenite and the influence of austenite chemistry and size on the stability. Kolsky bar compression experiments were conducted to isolate a situation where an adiabatic shear band propagated partway through the specimen. Examination of the microstructure in such a specimen showed both generations of austenite to be present far from the shear band, ahead of the shear band and adjacent to the shear band. The austenite immediately ahead of the shear band was fragmented. Within the shear band, evidence was found for deformation-induced transformation to martensite. These findings are discussed within the context of improved damage tolerance and ballistic resistance observed earlier in field tests.
DOI : 10.1007/s11661-020-05911-0
ISSN: 1073-5623 1543-1940
Sayı: 10
Cilt: 51
Sayfa: 5056-5076
27
Phase and Formation/Dissolution of Precipitates in Biomedical Co-Cr-Mo Alloys with Nitrogen Addition
Dergi Makalesi

Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Shingo Mineta
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2012
Metallurgical and Materials Transactions A
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The precipitates in as-cast and heat-treated biomedical Co-28Cr-6Mo-(0 to 0.35)C-(0.15 to 0.25)N alloys (mass pct) were investigated. Heat treatment was carried out at temperatures of 1473 K to 1573 K (1200 °C to 1300 °C) for holding periods of 0 to 43.2 ks. In the as-cast and heat-treated Co-Cr-Mo-N alloys, no precipitates were detected; nitrogen effectively inhibited the formation of the σ-phase and stabilized the face-centered cubic (fcc) metallic γ-phase. The precipitates observed in the as-cast and heat-treated Co-Cr-Mo-C-N alloys were of the M23X6 type, M2X type, π-phase (M2T3X type with a β-Mn structure), and η-phase (M6X-M12X type). Complete precipitate dissolution was detected in the alloys with carbon contents of less than 0.3 mass pct regardless of the nitrogen content. The main precipitates were of the M2X and M23X6 types after heat treatment for 1.8 to 43.2 ks. The π-phase precipitate was detected in the early stage of heat treatment at high temperatures. The formation of the M2X-type precipitate was enhanced by the addition of nitrogen, although the constitution of the precipitates depended on the balance between the nitrogen and carbon contents and the heat-treatment conditions.
DOI : 10.1007/s11661-012-1399-7
Anahtar Kelimeler : Complete Precipitate Dissolution, Main Precipitate Phase, Electric Resistance Tube Furnace, Differential Interference Contrast Mode, Effective Alloy Element
ISSN: 1073-5623 1543-1940
Sayı: 1
Cilt: 44
Sayfa: 494-503
28
Early Stages of Precipitation Process in Al-(Mn-)Sc-Zr Alloy Characterized by Positron Annihilation
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Martin Vlach , Jakub Cizek , Oksana Melikhova , Ivana Stulikova , Bohumil Smola , Tomas Kekule , Hana Kudrnova , Ryota Gemma , Volkmar Neubert
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2015
Metallurgical and Materials Transactions A
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Thermal effects on the precipitation stages in as-cast Al-0.70 at. pct Mn-0.15 at. pct Sc-0.05 at. pct Zr alloy were studied. The role of lattice defects was elucidated by positron annihilation spectroscopy (lifetime and coincidence Doppler broadening) enabling investigation of solutes clustering at the atomic scale. This technique has never been used in the Al-Sc- and/or Al-Zr-based alloys so far. Studies by positron annihilation were combined with resistometry, hardness measurements, and microstructure observations. Positrons trapped at defects are preferentially annihilated by Sc electrons. Lifetime of trapped positrons indicates that Sc atoms segregate at dislocations. Maximum fraction of positrons annihilated by Sc electrons occurring at 453 K (180 °C) suggests that clustering of Sc bound with vacancies takes place. It is followed by peak of this fraction at 573 K (300 °C). A rise of the contribution of trapped positrons annihilated by Zr electrons starting at 513 K (240 °C) and attaining maximum also at 573 K (300 °C) confirms that Zr participates in precipitation of the Al3Sc particles already at these temperatures. The pronounced hardening at 573 K (300 °C) has its nature in the precipitation of the Al3Sc particles with a Zr-rich shell. The contribution of trapped positrons annihilated by Mn electrons was found to be negligible.
DOI : 10.1007/s11661-015-2767-x
Anahtar Kelimeler : Ratio Curve, Isochronal Annealing, Positron Annihilation Spectroscopy, Positron Trapping, Trap Positron
ISSN: 1073-5623 1543-1940
Sayı: 4
Cilt: 46
Sayfa: 1556-1564
29
Carbon migration in 5Cr-0.5Mo/21Cr-12Ni dissimilar metal welds
Dergi Makalesi

Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
M. L. Huang , L. Wang
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
1998
Metallurgical and Materials Transactions A
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The carbon migration between a ferritic steel and an austenitic steel was studied in submerged arc-welded 5Cr-0.5Mo/21Cr-12Ni dissimilar metal welds (DMWs) after aging at 500°C for various times and after long-term service in technical practice. The distribution of carbon, chromium, nickel, and iron in the areas around the weld interface was determined by electron probe microanalysis, and the microstructural aspect in the carbon-depleted/enriched zone was characterized by optical microscopy and transmission electron microscopy (TEM). Furthermore, the precipitation sequences and composition characteristics of the carbides were identified by diffraction pattern microanalysis and energy-dispersive X-ray (EDX) microanalysis. It was found (1) that there exists a coherent relationship between intracrystalline M23C6 and the austenitic matrix; (2) that the composition of M23C6 in the carbon-enriched zone is independent of the duration of aging and service; (3) that the maximum carbon concentration is determined by the carbide type, the composition characteristic of precipitated carbides, and the concentration of carbide-forming Cr adjacent to the weld interface in the carbon-enriched zone; and (4) that the carbon migration in the 5Cr-0.5Mo/21Cr-12Ni DMWs can be described by a diffusion model.
DOI : 10.1007/s11661-998-0211-1
Anahtar Kelimeler : Carbide, Material Transaction, Austenitic Steel, Transmission Electron Microscopy Micrographs, Postweld Heat Treatment
ISSN: 1073-5623 1543-1940
Sayı: 12
Cilt: 29
Sayfa: 3037-3046
30
Understanding and Avoiding Intergranular Fracture Characteristics of Hadfield/Hot-Press-Forming Multi-Layer Steel Sheets
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Dergi Makalesi
Kaynak :
Springer Link
Dergi:
Metallurgical and Materials Transactions A
Yazar(lar) :
Min Cheol Jo , Jaeyeong Park , Gyeongbae Park , Hyeok Jae Jeong , Taejin Song , Hyoung Seop Kim , Nack J. Kim , Sunghak Lee
Konu :
Metals and Alloys, Mechanics of Materials, Condensed Matter Physics
Yıl :
2019
Metallurgical and Materials Transactions A
Yayıncı Web Sitesi
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Kaydet Alıntıla
An austenitic Hadfield steel shows highly sustained strain hardening as well as excellent tensile strength and ductility, but its yield strength is relatively low (400 to 500 MPa). In order to overcome this shortcoming, two multi-layer steel (MLS) sheets were fabricated by the hot-roll-bonding of the Hadfield steel with two kinds of martensitic hot-press-forming (HPF) steels. Carburized and decarburized layers were formed near Hadfield/HPF interfaces by the C diffusion from the high-C Hadfield (1.2 pct) to low-C HPF (0.23 and 0.35 pct) layers. The tensile test results indicated that the two MLS sheets were fractured right after the yielding with almost no plastic deformation because the intergranular fracture appeared in the carburized and HPF layers. This intergranular fracture was caused by Cr7C3 carbide precipitation and C segregation at prior austenite grain boundaries as well as considerably high residual stresses generated in both Hadfield and HPF layers. The tempering at 473 K (200 °C) was adopted for relieving residual stresses, while most of grain-boundary carbides remained. The 473 K (200 °C)-tempered MLS sheets showed improved tensile properties over the non-tempered MLS sheets, and well satisfied a rule of mixtures.
DOI : 10.1007/s11661-019-05346-2
ISSN: 1073-5623 1543-1940
Sayı: 9
Cilt: 50
Sayfa: 4085-4097

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