• Piri Keşif Aracı

1.  sayfa ve
1
Low temperature synthesis of nanocrystalline ?-Al2O3 by a tartaric acid gel method
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Materials Science and Engineering A
Yazar(lar) :
Kütahya Dumlupınar Üniversitesi
Konu :
?-Al2O3, Nanocrystals, Sol-gel, Tartaric acid
Yıl :
2008
Materials Science and Engineering A
Yayıncı Web Sitesi
Kaydet
Nanocrystalline alumina was synthesized by a simple sol-gel method using aluminum nitrate in tartaric, oxalic and acetic acids mixed aqueous solutions. The alumina gel was successfully transferred to ?-Al2O3 with this process after subsequent low temperature heat treatment. The prepared gel and powders were characterized by X-ray diffractometry (XRD), thermogravimetry-differential thermal analysis, scanning electron microscopy and transmission electron microscopy. The XRD analysis showed that the complete transformation from ?-Al2O3 nanocrystalline to ?-Al2O3 (37 nm) prepared in tartaric acid was observed at 925 °C. © 2007 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : ?-Al2O3, Nanocrystals, Sol-gel, Tartaric acid, article
Cilt: 475
Sayı: 01.Feb
ISSN: 0921-5093
Sınıflandırma :
Kimya %25
Kataliz %56
2
Effect of increased interfacial strength on the fatigue crack growth resistance and crack opening displacement of ß Ti21S/SCS 6 composites
Dergi Makalesi

Dergi Makalesi
Kaynak 1:
DSpace Makaleler
Kaynak 2:
DSpace Makaleler
Yayıncı :
Materials Science and Engineering A
Yazar(lar) :
Zonguldak Bülent Ecevit Üniversitesi
Konu :
Composites, Crack opening displacement, Fatigue crack growth, Fibre bridging, Interfacial strength
Yıl :
2008
Materials Science and Engineering A
Piri Tam Metin Bulucu
Kaydet
Fatigue crack growth resistance of metastable ß titanium composite was investigated in different heat treatment conditions. The effects of increased interfacial strength due to peak ageing on the fatigue crack growth, crack opening displacement and fibre bridging were examined and results of fibre fractures monitored by acoustic emission and fibre push back tests were correlated with fatigue crack growth and crack opening behaviour of the composites. It is shown that at maximum applied intensity factor values higher than crack arrest/catastrophic failure transition, peak ageing reduces the fatigue crack growth resistance of composite due to higher number of fibre fractures which occurs as fibre stress is increased due to increased interfacial shear stress. However, below transition heat treated composite shows better crack growth resistance compared to as-received condition under fixed Kmax,ini values. This favourable effect of increased interfacial strength on the crack growth behaviour is prominent in the composites with smaller initial unbridged defect size. © 2007 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.msea.2007.04.096
Anahtar Kelimeler : Composites, Crack opening displacement, Fatigue crack growth, Fibre bridging, Interfacial strength, article
Cilt: 476
Sayı: 01.Feb
ISSN: 0921-5093
Sınıflandırma :
3
Mechanical and wear properties of ultrafine-grained pure Ti produced by multi-pass equal-channel angular extrusion
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
G. Purcek , O. Saray , O. Kul , Güney Güven Yapıcı , M. Haouaoui , H. J. Maier
Konu :
Equal-channel angular extrusion, Ultrafine-grained materials, Titanium, Mechanical behavior, Wear
Yıl :
2009
Materials Science and Engineering: A
Yayıncı Web Sitesi
Kaydet
In this study, pure grade 2 Ti was processed via equal-channel angular extrusion (ECAE) for 8 and 12 passes following route-E at 300 °C. After processing, the microstructural evolution, tensile properties and wear behavior were investigated. ECAE-processed Ti exhibited a significant improvement in strength values with a slight decrease in ductility. However, the wear test results surprisingly showed that the strengthening of titanium by ECAE processing does not lead to the improvement of wear resistance at least for the pressures and sliding distances used in this study. This finding was mainly attributed to the tribochemical reaction leading to oxidative wear with the abrasive effect in Ti. Three distinct regions were formed on the subsurface of CG and UFG Ti after sliding wear, which are the tribolayer including titanium oxide with smeared wear material at the top, a deformed region having material structure oriented along the sliding direction in the middle, and the original unaffected bulk material at the bottom.
Anahtar Kelimeler : Article

ISSN: 0921-5093
Sınıflandırma :
4
CO2-induced mechanical behaviour of Hawkesbury sandstone in the Gosford basin: An experimental study
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Materials Science and Engineering A
Yazar(lar) :
Tharaka Dilanka Rathnaweera , Pathegama Gamage Ranjith , Samintha Perera , Asadul Haque , Aref Lashin , Nassir Al Arifi , Dornadula Chandrasekharam , Sheng-Qi Yang , Tao Xu , Shu Hong Wang , Ergül Yaşar
Konu :
CO2 sequestration, Saline aquifers, Strength, Crack formation, Microstructure, CO2 storage in Australia, Nanoscience & Nanotechnology, Materials Science, Multidisciplinary, Metallurgy & Metallurgical Engineering, Brines | Carbon Sequestration | Reactive Transport, CO2 sequestration, Carbon-dioxide, Saline aquifers, Dissolution kinetics, Aqueous-solutions, Storage, Solubility, Pressure, Model, Water, Acoustic emission testing, Aquifers, Calcite, Chemical analysis, Compressive strength, Crack closure, Crack initiation, Deformation, Hydrogeology, Mechanical properties, Mechanisms, Microstructure, Reservoirs (water), Saline water, Sandstone, Scanning electron microscopy, Water injection, X ray diffraction, Australia, CO2 sequestration, Microstructural changes, Saline aquifers, Strength, Unconfined compressive strength, Whole deformation process, X ray fluorescence analysis, Carbon dioxide
Yıl :
2015
Materials Science and Engineering A
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
Carbon dioxide (CO2) sequestered in saline aquifers undergoes a variety of chemically-coupled mechanical effects, which may cause CO2-induced mechanical changes and time-dependent reservoir deformation. This paper investigates the mineralogical and microstructural changes that occur in reservoir rocks following injection of CO2 in deep saline aquifers and the manner in which these changes influence the mechanical properties of the reservoir rocks. In this study, cylindrical sandstone specimens, 38 mm in diameter and 76 mm high, obtained from the Gosford basin, were used to perform a series of un-confined compressive strength (UCS) tests. Different saturation conditions: dry, water- and brine-saturated sandstone samples with and without scCO(2) (super-critical carbon dioxide) injection, were considered in the study to obtain a comprehensive understanding of the impact of scCO(2) injection during the CO2 sequestration process on saline aquifer mechanical properties. An acoustic emission (AE) system was employed to identify the stress threshold values of crack closure, crack initiation and crack damage for each testing condition during the whole deformation process of the specimens. Finally, scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses were performed to evaluate the chemical and mineralogical changes that occur in reservoir rocks during CO2 injection. From the test results, it is clear that the CO2-saturated samples possessed a lower peak strength compared to non-CO2 saturated samples. According to SEM, XRD and XRF analyses, considerable quartz mineral corrosion and dissolution of calcite and siderite were observed during the interactions of the CO2/water/rock and CO2/brine/rock systems, which implies that mineralogical and geochemical rock alterations affect rock mechanical properties by accelerating the collapse mechanisms of the pore matrix. AE results also reveal the weakening effect of rock pore structure with CO2 injection, which suggests a significant effect of CO2 on failure mechanisms of the reservoir rock, with CO2 saturation showing a significant influence on crack initiation and crack damage stages. (C) 2015 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.msea.2015.05.029
Anahtar Kelimeler : CO2 sequestration, Saline aquifers, Strength, Crack formation, Microstructure, CO2 storage in Australia, article
Cilt: 641
ISSN: 0921-5093
Sınıflandırma :
5
Static strain ageing behaviour of dual phase steels
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Materials Science and Engineering A
Yazar(lar) :
Gündüz S.
Konu :
Microalloyed steels, Prestrain, Static strain ageing
Yıl :
2008
Materials Science and Engineering A
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
In this work an investigation was conducted into the cold deformation ageing susceptibility of a carbon steel and a microalloyed steel, both with dual phase micro-structure. Ageing experiments after different prestrains were carried out at temperatures ranging from 25 to 250 °C. It was found that yield strength (YS) and tensile strength (UTS) of the steels with different dual phase micro-structures exhibit maximum values at ageing temperature of 100 °C after different prestrains. It is assumed that the first rise is based on the formation of solute atom atmospheres around dislocations and the further strengthening in the second step is caused by the low-temperature carbide precipitation in ferrite. When the ageing temperature increased to 150, 200 or 250 °C, YS decreased due to tempering effect in martensite. It was also found that the ageing of the microalloyed steel occurred more slowly than that of the carbon steel. The slow occurrence of ageing was clearly observed at temperatures of 100, 150, 200 and 250 °C and was attributed to the chemical composition of the steels. © 2007 Elsevier B.V. All rights reserved.
DOI : 10.1016/j.msea.2007.08.056
Anahtar Kelimeler : Microalloyed steels, Prestrain, Static strain ageing, article
Cilt: 486
Sayı: 01.Feb
ISSN: 0921-5093
Sınıflandırma :
6
Dispersion of mechanochemically activated SiC and Al2O3 powders
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Materials Science and Engineering A
Yazar(lar) :
Kütahya Dumlupınar Üniversitesi
Konu :
Al2O3, Dispersion, High-energy milling, Mechanochemical activation, SiC
Yıl :
2008
Materials Science and Engineering A
Yayıncı Web Sitesi
Kaydet
The mechanochemical milling is widely used as a top-down powder synthesis and preparation route. Coarse SiC and Al2O3 powders were ground with new high-energy mills running at 28 G for 30 min and 50 G for 5 min, respectively. The median particle size of SiC and Al2O3 was decreased from 500 to 1.46 µm and from 6.4 to 1.81 µm, respectively. Mechanochemically activated and agglomerated SiC and Al2O3 powders were dispersed using NH4 salt of polyacrylic acid in water. The median particle size of activated (or milled) Al2O3 and SiC powders was successfully reduced down to 0.72 and 0.48 µm, respectively, by colloidal dispersion. The activated and dispersed Al2O3 powders also exhibited enhanced densification. © 2007 Elsevier B.V. All rights reserved.
Anahtar Kelimeler : Al2O3, Dispersion, High-energy milling, Mechanochemical activation, SiC, article
Cilt: 475
Sayı: 01.Feb
ISSN: 0921-5093
Sınıflandırma :
7
An experimental and statistical study of interaction effects of matrix particle size, reinforcement particle size and volume fraction on the flexural strength of Al-SiC p composites by P/M using central composite design
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Materials Science and Engineering A
Yazar(lar) :
Diler E.A. , Ipek R.
Konu :
Central composite design, Flexural strength, Interaction, Matrix-reinforcement particle size ratio, Powder metallurgy
Yıl :
2012
Materials Science and Engineering A
Yayıncı Web Sitesi
Kaydet
In this study, the effects of reinforcement volume fraction, matrix and reinforcement particle sizes and their interactions on the flexural strength of Al-SiC p metal matrix composites manufactured by powder metallurgy method were investigated by using central composite design (CCD). An experimental plan for CCD with three factors and five levels was used to optimize the required number of experiments. The fabricated composites were reinforced with SiC particles of 2.39, 7.5, 15, 22.5 and 27.61 volume fractions. The particle sizes of 45, 62, 87, 112, and 129µm were determined for both matrix and reinforcement particles. Experimental and numerical results show that the main effects of factors and their interactions are significant on the flexural strength. Among all factors, the main effect of volume fraction dominates the main effect of other two factors. Interaction between matrix particle size and reinforcement particle size is much more important at low volume fraction compared to that at high volume fraction. The high flexural strength values at low volume fractions are obtained when matrix particle size is equal to or smaller than reinforcement particle size while those at high volume fraction can be only reached when matrix particle size is much smaller than that of reinforcement particle. © 2012 Elsevier B.V.
Anahtar Kelimeler : Central composite design, Flexural strength, Interaction, Matrix-reinforcement particle size ratio, Powder metallurgy, article
Cilt: 548
ISSN: 0921-5093
Sınıflandırma :
8
High temperature characteristics of Al2024/SiC metal matrix composite fabricated by friction stir processing
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Materials Science and Engineering A
Yazar(lar) :
Ali Hosseinzadeh Ghobadlou , Güney Güven Yapıcı
Konu :
Friction stir, Aluminum, MMC, SiC, Fracture, High temperature
Yıl :
2018
Materials Science and Engineering A
Yayıncı Web Sitesi
Kaydet
In the present study, friction stir processing (FSP) is used for the synthesis of an aluminum metal matrix composite (MMC) reinforced by SiC particles. MMC specimens with reinforced microstructures exhibited significant improvement in hardness (near 50%). Isothermal uniaxial tensile tests were employed for the as-received, friction stir processed and composite microstructures at ambient and high temperatures under strain rates ranging from 10−2 to 10−4 s−1 to investigate the effect of deformation rate on the mechanical behavior. At ambient temperature, notable improvement of the yield strength was observed reaching about 240% of the as-received samples while the ductility was reduced near to 4%. Elevated temperature flow curves were perceptibly sensitive to strain rate, especially for FSPed and MMC samples. Fracture surface observations hinted at the distribution of second phase particles along with possible damage mechanisms.
Anahtar Kelimeler : Article

ISSN: 0921-5093
Sınıflandırma :
9
Formation of novel flower-like silicon phases and evaluation of mechanical properties of hypereutectic melt-spun Al-20Si-5Fe alloys with addition of V
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Materials Science and Engineering A
Yazar(lar) :
Bülent Ecevit Üniversitesi
Konu :
Al-Si alloys, Fe-containing intermetallics, Melt spinning, Vanadium
Yıl :
2014
Materials Science and Engineering A
Yayıncı Web Sitesi Piri Tam Metin Bulucu
Kaydet
In this work, rapidly solidified hypereutectic Al-20Si-5Fe-. XV (X=0, 0.5 and 1) alloys were fabricated by melt spinning under vacuum. Microstructural and spectroscopic analyses were performed using SEM, TEM, TEM-MAPing, TEM-EDS and XRD measurements. Mechanical properties of the alloys were determined using DSI measurements. Experimental results indicated that addition of 0.5. wt% V to melt-spun Al-20Si-5Fe alloys induced formation of a novel flower-like Si phase. And addition of higher amount V (1. wt%), caused formation of refined Si phases and mostly hindered formation of Fe-bearing intermetallics. Observations along with manuscript strongly indicate that V modifies the Si phases by the impurity induced twinning (IIT). Changes in the dynamic microhardness of the samples were mainly determined by the size of Si phases. Addition of vanadium led to quite lower elastic modulus in the vanadium added alloys compared to base alloy. © 2014 Elsevier B.V.
DOI : 10.1016/j.msea.2014.04.025
Anahtar Kelimeler : Al-Si alloys, Fe-containing intermetallics, Melt spinning, Vanadium, article
Cilt: 607
ISSN: 0921-5093
Sınıflandırma :
10
Effect of commercial purity levels on the mechanical properties of ultrafine-grained titanium
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Materials Science and Engineering A
Yazar(lar) :
G. Purcek , Güney Güven Yapıcı , I. Karaman , H. J. Maier
Konu :
Equal-channel angular extrusionpressing, Grade-2, grade-4 CP-Ti, Ultrafine-grained materials, Microstructure, Mechanical properties
Yıl :
2011
Materials Science and Engineering A
Yayıncı Web Sitesi
Kaydet
Two grades of commercial purity (CP) titanium (grades 2 and 4) were processed using equal-channel angular extrusion (ECAE) at 300 ◦C and 450 ◦C, respectively. The processing temperatures were the minimum temperatures at which eight pass ECAE could be performed without any shear-localization. The coarse-grained (CG) microstructures of as-received grade-2 and grade-4 CP-Ti, with average grain sizes of 110_m and 70_m, respectively, were refined down to sub-micron levels with a mean grain size of about 300nm for both grades after 8 ECAE passes. The ultrafine-grained (UFG) microstructures led to substantial enhancement in strength for both grades. The grade-2 sample showed a more than two fold increase in yield strength (_y), from 307MPa for the as-received one to about 620MPa for the processed samples. The grade-4 CP-Ti exhibited a relatively smaller increase in strength due to the higher processing temperature, and it showed about 50% increase in _y after eight pass ECAE, from 531 to 758 MPa. These strength levels were obtained with high ductility levels of 21% and 25% for UFG grade-2 and grade-4 Ti, respectively. These improvements in mechanical properties are attributed to the substantially refined grain size and increased dislocation density. Grade-4 Ti is stronger than grade-2 because of the higher oxygen content. The higher ductility and significantly higher strain hardening capability of UFG grade-4 Ti, in spite of the similar grain size and microstructure with UFG grade-2 Ti, is also due to the higher impurity content, probably resulting in a higher dislocation storage capability during room temperature deformation, and thus, higher strain hardening capacity. Such properties make UFG grade-4 Ti comparable to the commercial Ti–6Al–4V alloy for biomedical applications without negative effects of the alloying elements on biocompatibility.
Anahtar Kelimeler : Article

ISSN: 0921-5093
Sınıflandırma :
11
On the mechanical behavior of cold deformed aluminum 7075 alloy at elevated temperatures
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Materials Science and Engineering A
Yazar(lar) :
 Kambiz Shojaei , Seyed Vahid Sajadifar , Güney Güven Yapıcı
Konu :
7075 aluminum alloy, Plastic deformation, High temperature forming, Rate sensitivity, Cold work, Fracture morphology
Yıl :
2016
Materials Science and Engineering A
Yayıncı Web Sitesi
Kaydet
In the present study, elevated temperature deformation behavior and microstructural evolution of 7075 aluminum alloy at annealed and cold rolled conditions were examined. Isothermal uniaxial tensile tests at a temperature range of 200–350 °C and at a strain rate range of 0.001–0.1 s−1 were conducted to investigate the effects of deformation parameters on the mechanical behavior. High temperature flow was noticeably strain rate sensitive especially for the rolled condition. Cold work was shown to have a remarkable influence on increasing the peak stress up to 250 °C. At and above this temperature the rolled microstructure enabled higher ductility reaching over 50% accompanied by a stress plateau. The ductility drop at 350 °C at the slowest deformation rate was attributed to impurity rich regions with possible formation of secondary phases due to dynamic precipitation.
Anahtar Kelimeler : Article

ISSN: 0921-5093
Sınıflandırma :
12
Solid-liquid interfacial energy of camphene
Dergi Makalesi

Dergi Makalesi
Kaynak :
DSpace Makaleler
Yayıncı :
Materials Science and Engineering A
Yazar(lar) :
Niğde Ömer Halisdemir Üniversitesi
Konu :
Crystal growth, Gibbs-Thomson coefficient, Solid-liquid interfacial energy
Yıl :
1999
Materials Science and Engineering A
Yayıncı Web Sitesi
Kaydet
The Gibbs-Thomson coefficient and the solid-liquid interfacial energy for camphene have been measured to be (8.58 ± 0.96) × 10-8 K m and (4.43 ± 0.49) × 10-3 J m-2, respectively, by a direct method. The grain boundary energy of camphene has also been calculated to be (8.36 ± 0.92) × 10-3 J m-2 from the observed grain boundary groove shapes. © 1999 Elsevier Science S.A. All rights reserved.
Anahtar Kelimeler : Crystal growth, Gibbs-Thomson coefficient, Solid-liquid interfacial energy, article
Cilt: 270
Sayı: 2
ISSN: 0921-5093
Sınıflandırma :
13
Effects of processing on mechanical properties of B4C-graphene composites fabricated by hot pressing
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Aiyang Wang , Chun Liu , Lanxin Hu , Tian Tian , Qianglong He , Weimin Wang , Hao Wang , Zhengyi Fu
Yıl :
2021
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
Boron carbide (B4C) composites with 4 wt% graphene were fabricated by hot pressing (HP) using two different graphene sources, graphene nanoplatelets (GNPs) and graphene oxide (GO), and two different homogenization methods. B4C–GNPs/GO powder mixtures were homogenized by planetary ball milling and a heterogeneous co-precipitation method using cetyltrimethyl ammonium bromide (CTAB) as the cationic surfactant. The influences of homogenization methods and types of graphene source on the microstructure and mechanical properties of B4C composites were investigated. A maximum flexural strength of 476 MPa was achieved for B4C–GNPs composites homogenized using planetary ball milling with previous ultra-sonication of GNPs in ethanol. Additionally, the fracture toughness of B4C composites was in the range 3.85–5.51 MPa m1/2, which was significantly higher than that of monolithic B4C. Fractography was also performed to evaluate the individual homogenization method. Based on the different processing techniques, the critical flaw sizes of the B4C composites varied from 45 μm to 112 μm. The results reveal that the main fracture origins are processing flaws in the form of structural heterogeneities, graphene agglomerations, and interfacial porosity.
DOI : 10.1016/j.msea.2021.140872
Anahtar Kelimeler : Boron carbide, Graphene, Homogenization, Hot pressing, Fractography
Cilt: 808
Sayı: 0
Sayfa: 140872-0
ISSN: 0921-5093
14
From as-cast to heat treated X-40 superalloy: Effect of cooling rate after partial solution treatment on microstructural evolutions and mechanical properties
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Ali Ghasemi , Ali Mohammad Kolagar , Majid Pouranvari
Yıl :
2021
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
This research study aims at investigating the influence of partial solution treatment and the subsequent cooling strategy on the microstructure and mechanical properties of an as-cast Co–Cr–W superalloy. Three different cooling scenarios were employed to explore the effect of cooling rate on the carbide reprecipitation potential from the \solid solution formed during the heat treatment. The partial dissolution/breakdown of the continuous network of the Cr-rich M7C3 carbides during the partial solution treatment cycle along with their transformation to M23C6 carbides and formation of secondary carbides during the cooling stage were taken into account to discuss the obtained hardness values, and high-temperature creep results. Regardless of the applied cooling rate, the secondary carbides were formed during the cooling stage, and the heat-treated samples showed almost the same microstructure and mechanical properties, which eliminates the need for the aging cycle. This can alleviate the concerns associated with the heat treatment of the large-size X-40 industrial components since the gradient in the cooling rate after the heat treatment cycle would not lead to non-uniform parts. From the hardness and creep viewpoints, all of the samples could meet the minimum requirements of the X-40 superalloy. Mechanical properties suggest that the applied partial solution treatment cycle can be considered as a suitable candidate for high-temperature applications of X-40 superalloy.
DOI : 10.1016/j.msea.2021.140891
Anahtar Kelimeler : Cobalt-based superalloy, Microstructure, Creep rupture, Hardness, Partial solution treatment, Cooling rate
Cilt: 808
Sayı: 0
Sayfa: 140891-0
ISSN: 0921-5093
15
Investigation on the size and distribution effects of O phase on fracture properties of Ti2AlNb superalloy by using image-based crystal plasticity modeling
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Yanqi Fu , Manqian Lv , Qing Zhao , Haiming Zhang , Zhenshan Cui
Yıl :
2021
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
Ti2AlNb superalloy consisting of O-phase and B-phase often exhibits deformation heterogeneity and incompatibility due to the mechanical characteristics of phases. To study the size and distribution effects of the O-phase on the fracture properties of Ti2AlNb superalloy, three types of material with different O-phase sizes and distributions were prepared through heat treatments, and the tensile properties of the heat-treatment samples were investigated. An image-based crystal plasticity model was built based on the backscattered electron images of the superalloy to probe the effects of O-phase size and distribution on stress, strain partitioning, and fracture. The strain hardening and fracture behaviors were discussed in terms of the strain partitioning between O-phase and B-phase, and the formation and propagation of micro-cracks, respectively, by combining the simulation and experimental results. Simulation results show the stress and strain partitioning between O/B phase interfaces increases with the increase of O-phase size, and micro-cracks are formed when the local stress concentration exceeds the critical value. The presence of micro-cracks imposes high shear stress on the neighboring B-phase matrix and promotes fast crack propagation through the B-phase matrix, resulting in cleavage fracture. Inversely, micro-cracks tips can be alleviated when the stress concentration at O/B phase interfaces can be relaxed by the plastic deformation of the B-phase matrix. The variation of stress and strain partitioning with deformation during plastic deformation shows that strain partitioning isnt related to O-phase size, but stress partitioning depends on it. Thus, the effects of O-phase size on fracture mainly depend on stress partitioning. This paper presents a meaningful method to model the phase distribution, and the effects of O-phase size and distribution on stress, strain partitioning, and fracture behavior are studied.
DOI : 10.1016/j.msea.2021.140787
Anahtar Kelimeler : Dual-phase superalloy, Strain partitioning, Fracture characteristics, Crystal plasticity modeling
Cilt: 805
Sayı: 0
Sayfa: 140787-0
ISSN: 0921-5093
16
A 2000 MPa grade Nb bearing hot stamping steel with ultra-high yield strength
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Jiangtao Liang , Hongzhou Lu , Leilei Zhang , Feng Li , Ronghua Cao , Kun Liu , Hui Pan , Huaxiang Teng , Xuetao Li , Aimin Guo , Zhengzhi Zhao
Yıl :
2021
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
This study reports a novel 2000 MPa grade ultra-strong hot stamping steel, which contains lath martensite, nanometer-sized film-shaped retained austenite and precipitates. The yield strength significantly increases with increasing tempering temperature as the precipitation strengthening, grain refinement strengthening and reducing microstructure residual stress. Multi-strengthening mechanisms (i.e. grain refinement strengthening, precipitation strengthening and transformation-induced plasticity effect) work together to improve the strength and plasticity at the same time. The yield strength reached 1600 MPa, together with an ultimate tensile strength of 1939 MPa and total elongation of 9.14% when tempered at 573 K. Compared with commercial 22mnB5 steel, the tested steels have remarkable improvement in mechanical properties.
DOI : 10.1016/j.msea.2020.140419
Anahtar Kelimeler : Hot stamping steel, Yield strength, Retained austenite, Nanometer-sized carbide precipitates
Cilt: 801
Sayı: 0
Sayfa: 140419-0
ISSN: 0921-5093
17
An anomalous effect of grain refinement on yield stress in friction stir processed lightweight steel
Dergi Makalesi

Dergi Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
B. Mirshekari , A. Zarei-Hanzaki , A. Barabi , H.R. Abedi , S.J. Lee , H. Fujii
Yıl :
2021
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
Friction stir processing was utilized for enhancing mechanical properties of a lightweight steel through development of fine grain structures with high austenite stability. Interestingly, an anomalous effect of grain refinement on yield stress was found which was justified considering the dominant strain accommodative mechanisms in the initial and processed microstructures.
DOI : 10.1016/j.msea.2020.140057
Anahtar Kelimeler : Friction stir processing, Hall-petch effect, Grain refinement, Yielding behavior, Transformation induced plasticity
Cilt: 799
Sayı: 0
Sayfa: 140057-0
ISSN: 0921-5093
18
Effect introduced high density of precipitates on the microstructural evolutions during multi-direction forging of Al–Zn–Mg–Cu alloy
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Jiuhui Zhao , Yunlai Deng , Jianguo Tang , Jin Zhang
Yıl :
2020
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
Large number density of coarse precipitates were introduced into the Al–Zn–Mg–Cu alloy by interrupted aging and then over-aging at 300 °C. Both the overaged and homogenized samples were isothermal MDFed at 5 × 10−3 s−1 with temperatures ranging from 300 °C to 450 °C to investigate the effect of high number density of precipitates on the microstructural evolutions. The results showed that the precipitates decreased gradually during MDF of overaged samples at 300 °C and 350 °C while they were almost dissolved at 400 °C and 450 °C. And as the result of that the precipitates could pin dislocations during deformation, and much greater grain refinement was achieved during MDF of overaged samples at 300 °C and 350 °C.
DOI : 10.1016/j.msea.2020.139927
Anahtar Kelimeler : Multi-directional forging, Alu2013Znu2013Mgu2013Cu alloys, Recrystallization mechanism, Grain refinement
Cilt: 798
Sayı: 0
Sayfa: 139927-0
ISSN: 0921-5093
19
The mechanism of internal fatigue-crack initiation and early growth in a titanium alloy with lamellar and equiaxed microstructure
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Xiangnan Pan , Shouwen Xu , Guian Qian , Alexander Nikitin , Andrey Shanyavskiy , Thierry Palin-Luc , Youshi Hong
Yıl :
2020
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
Traditionally, equiaxed α grains rather than lamellar microstructure (LM) domains in titanium alloys are regarded as potential internal crack origins in high-cycle fatigue (HCF) and very-high-cycle fatigue (VHCF) regimes. Here, we found that the fatigue crack is prone to initiate from a large LM domain in a titanium alloy with the composition of LM and equiaxed microstructure (EM) of fine α grains. Then, the mechanisms of internal crack initiation and early growth for the cases of HCF and VHCF under stress ratio R = −1, 0.1 and 0.5 were addressed and a mechanism chart was constructed to illustrate the internal cracking behavior, especially showing that the numerous cyclic pressing process dominates the related microstructure evolution with grain size refinement and nanograin formation underneath the fracture surfaces in the region of crack initiation and early growth.
DOI : 10.1016/j.msea.2020.140110
Anahtar Kelimeler : Titanium alloy, Crack initiation, Facet, Very-high-cycle fatigue, Lamellar microstructure
Cilt: 798
Sayı: 0
Sayfa: 140110-0
ISSN: 0921-5093
20
Implications of post-processing induced microstructural changes on the deformation and fracture response of additively manufactured Ti–6Al–4V
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Lara Draelos , Peeyush Nandwana , Ankit Srivastava
Yıl :
2020
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
Ti–6Al–4V parts fabricated via electron beam melting (EBM) powder bed fusion are often subjected to hot isostatic pressing below the β-transus temperature to mitigate defects. During which the pressure aids in pore closure and the thermal exposure results in coarsening of α phase while retaining the columnar prior-β phase grain morphology present in the as-fabricated condition. The same post-processing treatment can also be carried out above β-transus temperature which is an effective way to modify both the grain morphology and the associated α textures. The objective of this work is to correlate thermally induced microstructural changes to the deformation and fracture response of the EBM processed Ti–6Al–4V. To this end, we have carried out both sub-transus and super-transus heat-treatments of the as-fabricated material. The mechanical response of the as-fabricated and all heat-treated materials are characterized by in-situ tensile tests under a high-resolution digital optical microscope. This enabled us to capture large-scale panoramic images of the deforming microstructure, and overcome the trade-off between the image resolution and the field of view during in-situ experiments. The series of images captured throughout the imposed deformation are subsequently used to perform microstructure-based digital image correlation to measure microstructural-scale strains over a large area. The results of the in-situ tests together with detailed fractographic analyses are then used to elucidate how the heterogeneous deformation spanning over multiple microstructural length-scales, for example, at the scale of lamellae, colonies of lamellae and grain boundaries, affect the overall deformation and fracture response of the post-processed materials.
DOI : 10.1016/j.msea.2020.139986
Anahtar Kelimeler : Characterization, Additive manufacturing, Titanium alloys, In situ tension test, Digital image correlation, Fracture behavior
Cilt: 795
Sayı: 0
Sayfa: 139986-0
ISSN: 0921-5093
21
Achieving enhanced mechanical properties in Mg-Gd-Y-Zn-Mn alloy by altering dynamic recrystallization behavior via pre-ageing treatment
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Kui Wang , Xiaoxu Dou , Jingfeng Wang , Yuanding Huang , Sarkis Gavras , Norbert Hort , Shijie Liu , Hao Hu , Jinxing Wang , Fusheng Pan
Yıl :
2020
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
The effects of pre-ageing treatment on the microstructure and mechanical properties of the Mg-9.2Gd-4.4Y-1.0Zn-0.8Mn (wt.%) alloy were investigated. Microstructural analysis indicated that the ageing treatment before extrusion led to the formation of dense prismatic β′ and basal γ′ precipitates in heat treated alloys. The presence of these precipitates and their solution obstructed the dynamic recrystallization process during hot extrusion. The lamellar long-period stacking ordered (LPSO) phases restrained the recrystallization through forming the kink band and releasing the stress concentration, and the fine β-Mg5(Gd, Y) particles suppressed the recrystallization by the particle pinning effect. The block-shaped LPSO phases and coarse β-Mg5(Gd, Y) particles promoted the recrystallization following the particle stimulated nucleation (PSN) mechanism. The combined effects led to the formation of the bimodal microstructure, which shows fine recrystallized grains with random grain orientation and deformed grains with strong fiber texture. The bimodal microstructure with lower recrystallization fraction provides the alloy higher strength and lower ductility. With solid-solution and pre-ageing treatments, the as-extruded alloy shows the best strength-ductility balance with an ultimate tensile strength (UTS) of 455 MPa, tensile yield strength (TYS) of 382 MPa and elongation to failure (EL) of 11.0%. The outstanding mechanical properties are mainly attributed to the bimodal microstructure, strong fiber texture, β-Mg5(Gd, Y) particles, lamellar and block-shaped LPSO phases.
DOI : 10.1016/j.msea.2020.139635
Anahtar Kelimeler : Mg-Gd-Y-Zn-Mn alloy, Heat treatments, Morphology, Long-period stacking ordered phase, Mechanical properties
Cilt: 790
Sayı: 0
Sayfa: 139635-0
ISSN: 0921-5093
22
A study on the effect of chemical composition on the microstructural characteristics and mechanical performance of DP1000 resistance spot welds
Araştırma Makalesi

Araştırma Makalesi Open Access
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Ali Chabok , Ellen van der Aa , Yutao Pei
Yıl :
2020
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
This paper reports on the factors governing the mechanical properties of resistance spot welded hot dip galvanized DP1000 under tensile-shear and cross-tension loading. In particular the effects of chemical composition on the microstructural evolution and mechanical properties of DP1000 resistance spot welds are studied thoroughly, by comparison of a higher and lower carbon alloying approach. It is shown that DP1000 steel with higher carbon content attains a martensitic microstructure in the weld nugget with smaller prior austenite grains and finer block sizes. The intervariant boundary fraction analysis also reveals that DP1000 steel containing lower carbon content shows stronger variant selection as the fraction of variants belonging to the same Bain group is higher for this steel. Intervariant plane distribution also reveals that the most of intervariant boundaries for both steels terminated at or near {011} slip planes. Mechanical testing of the welds reveals that the steel with higher carbon content shows a better mechanical performance in tensile-shear test, whereas the DP steel with a lower carbon content exhibits higher maximum load of cross-tension test. The key factors controlling the mechanical response of resistance spot welds during two different mechanical tests are explored via nanoindentation, slit-milling method combined with digital image correlation and micro-cantilever bending. It is demonstrated that the strength and/or hardness of the weld nugget is the key parameter governing the tensile-shear strength of the spot welds, while the fracture toughness of the weld is the dominant parameter that determines the cross-tension strength.
DOI : 10.1016/j.msea.2020.139501
Anahtar Kelimeler : Resistance spot welding, Nanoindentation, Micro-cantilever bending, Fracture toughness, Tensile-shear strength, Cross-tension strength
Cilt: 788
Sayı: 0
Sayfa: 139501-0
ISSN: 0921-5093
23
Effect of post heat treatment on microstructure and mechanical properties of Ti-6Al-4V jointing parts proceeded by laser additive manufacturing
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Wei Wang , Di Wang , Changfu Li , Guang Yang , Yuhang Ren , Lanyun Qin
Yıl :
2020
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
Laser Deposition Manufacturing (LDM) provides a novel jointing method to realize metal parts fabrication, which is one of the key research directions for preparing large integral titanium alloy components. Based on LDM, pairs of forged Ti-6Al-4V titanium alloy parts with special designed V shape groove were jointed, followed by post heat treatments which implemented effective adjustment of tensile properties of the joints, to investigate the mechanical performance. Optical microscope (OM), XRD diffraction and transmission electron microscope (TEM) analysis were performed to analysis microstructure in the deposition zone and substrate, the mechanism that evokes mechanical properties variation concerning about heat treatments was also proposed. Lamellar α cluster distributed in the original β column crystal was the overall feature for the deposition zone of the joint pieces. Due to the heat flux of the melting pool, heat-affected zone was introduced about 0.3–0.5 mm in thickness. The post-heat treatment process significantly changed the mechanical properties of both the substrate and the deposition zone. As-deposited and solution + aging treatment gave rise to the joint pieces at higher tensile strength relative to aging and annealing treatment, which reduced the strength of the pieces, and the annealing treatment weakened the strength of the deposition area lower than that of the substrate. Post heat treatment processes effectively changed the ratio, size and distribution of α and β phases in the deposition zone, i.e., the increase of lamellar structure in width, length, and βT portion in the whole structure were the main factor that leading to the decline of strength performance of the junction area.
DOI : 10.1016/j.msea.2020.139544
Anahtar Kelimeler : Laser additive manufacturing, Titanium alloy, Heat treatment, Microstructure, Mechanical properties
Cilt: 788
Sayı: 0
Sayfa: 139544-0
ISSN: 0921-5093
24
Designing of a thin Mo diffusion barrier towards strong and reliable Ti/Cu dissimilar brazing
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Yongqiang Deng , Wei Cong , Huibin Xu
Yıl :
2020
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
The dissimilar brazing of Ti and Cu has been recognized to be challenging owing to the affinity of forming brittle intermetallic compounds at joint interface. In the current investigation, it was demonstrated that such detrimental interfacial reaction products can be readily circumvented by employing a Mo diffusion barrier deposited on Ti substrate. Combining Mo interlayer and a Ag–Cu–Ti active filler alloy, intermetallic compounds free Ti/Cu brazed joints consisting of Ti–Mo solid solution, Mo interlayer and remnant braze can be obtained. As a result of the eradication of brittle phases, the resultant joints exhibit excellent structural integrity with bonding strength comparable to the parent material properties. Additionally, as a consequence of sluggish solid state diffusion at the Ti/Mo interface and limited dissolution of the Mo interlayer by filler alloy during brazing, the desirable joint microstructure can be reproduced within a wide range of bonding duration. Such results indicate that strong and reliable Ti/Cu dissimilar brazing can be achieved by the combination of a Mo diffusion barrier and Ag–Cu–Ti active filler alloy.
DOI : 10.1016/j.msea.2020.139469
Anahtar Kelimeler : Titanium, Copper, Brazing, Diffusion barrier, Interfacial microstructure, Mechanical properties
Cilt: 786
Sayı: 0
Sayfa: 139469-0
ISSN: 0921-5093
25
Effect of Si content on microstructures, tensile properties, and creep properties in a cast Mg–6Al-0.4Mn–2Ca (wt.%) alloy
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
T. Nakata , C. Xu , T. Sakai , T. Miyamoto , J. Liao , S. Kamado
Yıl :
2020
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
Effect of Si content on microstructures, tensile properties, and creep properties in a gravity-cast Mg–6Al-0.4Mn–2Ca (wt.%, AMX6042) alloy has been investigated. High content of Si addition increases the ductility of the AMX6042 alloy without large loss of strengths; however, addition of Si over 0.6 wt.% decreases fraction of (Mg,Al)2Ca phases significantly. Moreover, such high content of Si promotes formation of Mg17Al12 phases, leading to poor creep properties. Although addition of Si tends to decrease fraction of (Mg,Al)2Ca phases and promote formation of Mg17Al12 phases, good creep properties could be kept up to 0.47 wt.% Si addition.
DOI : 10.1016/j.msea.2020.139018
Anahtar Kelimeler : Mg-Al-Mn-Ca alloy, Gravity-cast, Tensile property, Creep property, Dynamic precipitation
Cilt: 776
Sayı: 0
Sayfa: 139018-0
ISSN: 0921-5093
26
Abnormal softening of Ti-metallic glasses during nanosecond laser shock peening
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Yansen Li , Kun Zhang , Yang Wang , Weiqi Tang , Yating Zhang , Bingchen Wei , Zheng Hu
Yıl :
2020
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
Nanosecond laser shock peening (NLSP) has been proved to be an effective way to enhance the mechanical properties of metallic components through modifying the surface microstructures. However, the micromechanism of structure and property fluctuations induced by shock wave propagation is still limited due to the intrinsic defects in crystalline materials. Here, NLSP treatment has been performed into the Ti-metallic glasses. Owing to the absence of dislocations, grain boundary and phase segregation, the structural signals caused by the shock wave could come into sight. According to grid nanoindentation results, the shock-affected region can be divided into three sections: (I) the rapid softening region, (II) the recovery region and (III) the matrix region. The fronted first pop-in event and the reduced hardness found in the subsurface region provide clear evidence of the release wave-induced structural rearrangement. The abnormal change of the average volume of the shear transformation zone (STZ) could be explained by a two-step transformation mechanism, due to the fluctuations of the “weak spot” induced by the release stress wave. By means of these results, this work provides an opportunity to shed light on the common laser-solid interaction.
DOI : 10.1016/j.msea.2019.138844
Anahtar Kelimeler : Laser shock wave, Metallic glass, Grid nanoindentation
Cilt: 773
Sayı: 0
Sayfa: 138844-0
ISSN: 0921-5093
27
Effect of microstructure evolution on the creep properties of a polycrystalline 316H austenitic stainless steel
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Jianan Hu , Graham Green , Simon Hogg , Rebecca Higginson , Alan Cocks
Yıl :
2020
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
Creep deformation and failure is one of the most critical life limiting factors of structural components used at elevated temperatures, such as in nuclear power plants. Understanding of the mechanisms of creep in nuclear power plant steels, such as Type 316H austenitic stainless steels, is still incomplete. It has been observed that long-term creep curves of initially solution-treated (ST) 316H stainless steels exhibit multiple secondary stages at the operational temperature and stress range. This paper probes the internal mechanisms for this complex phenomenon by correlating and quantifying the evolution of microstructural state (dislocations, precipitation and solid solution elements) and its mechanistic influence on the materials creep properties. This is examined for the first time by a multi-scale self-consistent crystal plasticity framework combined with a simple classical phase transformation model and thermal solute strengthening model. The novel integrated model is capable of describing a broad range of physical processes, including dislocation multiplication (hardening) and climb-controlled recovery, precipitation nucleation, growth and coarsening (Ostwald Ripening) and thermal solute dragging. The mechanisms responsible for the observed multiple secondary stages in the creep curves of initially solution-treated 316H stainless steels are explained through the strengthening and softening effects associated with these processes.
DOI : 10.1016/j.msea.2019.138787
Anahtar Kelimeler : Microstructure evolution, Creep property, Phase transformation, Stainless steel
Cilt: 772
Sayı: 0
Sayfa: 138787-0
ISSN: 0921-5093
28
Mechanism of crack initiation and early growth of high strength steels in very high cycle fatigue regime
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
Qingyuan Song , Chengqi Sun
Yıl :
2020
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
In this paper, we capture the evolution characteristic of interior crack initiation and early growth of a bearing steel (GCr15) with tensile strength bigger than 2000 MPa in very high cycle fatigue (VHCF) regime by variable amplitude loadings. The traces left on the fracture surface suggest that the equivalent crack growth rate in crack initiation and early growth stage is of the magnitude 10−12-10−11 m/cyc. Transmission electron microscopy (TEM) observation further shows that there are discontinuous refined grain regions beneath the fracture surface in the crack initiation and early growth region. Moreover, the compressive fatigue test is performed on the specimen of a martensitic stainless steel (AISI630) with a pre-crack, and no grain refinement phenomenon is observed in the vicinity of the crack tip and beneath the crack surface by the electron backscatter diffraction (EBSD). The present results support the mechanism of the crack initiation and early growth of high strength steels in VHCF regime: the crack initiation and early growth is attributed to the grain refinement caused by the dislocation interaction over a number of cyclic loadings followed by micro cracks along with the formation of micro cracks irrespective of the grain refinement during the cyclic loading.
DOI : 10.1016/j.msea.2019.138648
Anahtar Kelimeler : very high cycle fatigue, High strength steels, Crack initiation mechanism, Crack growth rate, Grain refinement
Cilt: 771
Sayı: 0
Sayfa: 138648-0
ISSN: 0921-5093
29
Influence of processing parameters on internal porosity and types of defects formed in Ti6Al4V lattice structure fabricated by selective laser melting
Araştırma Makalesi

Araştırma Makalesi
Kaynak :
Science Direct
Yayıncı :
Materials Science and Engineering: A
Yazar(lar) :
H. Salem , L.N. Carter , M.M. Attallah , H.G. Salem
Yıl :
2019
Materials Science and Engineering: A
Yayıncı Web Sitesi Tam Metin
Kaydet
Ti6Al4V lattice structures were fabricated using selective laser melting with a wide range of processing parameters, namely laser power and scan speed, in order to study their effect on strut diameter and internal porosity morphology. Hence, identifying the optimum processing condition. Scanning electron microscopy (SEM) and optical microscopy (OM) were used to investigate the influence of these parameters on the strut size and internal porosity within the struts. The results show that at low laser power conditions the strut size decreased with increasing the scan speed. At intermediate laser power (200 W) the strut size decreased until it reached 2400 mm/s, beyond which no pattern was observed. Fluctuations in strut size values were found at different scan speeds using high laser power (250 W, 300 W). The micrographs of the sectioned lattice structures showed various morphologies of the internal porosity, from which a process map was developed to pinpoint the various types of defects at the different processing conditions. Five zones were formed which are: gas porosity, keyholing, irregular defects, balling, and lack of fusion defects. SLM processing condition of 100 W–1600 mm/s was selected to be the best condition from the studied samples for producing the lattice structure with strut size closest to the design and with minimum internal porosity. Mechanical and microstructural analysis were performed for this condition.
DOI : 10.1016/j.msea.2019.138387
Anahtar Kelimeler : Selective laser melting, Lattice structure, Parametric study, Defects, Mechanical properties
Cilt: 767
Sayı: 0
Sayfa: 138387-0
ISSN: 0921-5093

Yayın Yılı

Sınırla

Doküman Türü
Tümü

Disiplin
Tümü

Disipline Göre İlgililik

Alt Disiplin
Tümü

Konu
Tümü

Dergi İsmi
Tümü

Veri Tabanı
Tümü

Lisan
Tümü

X
Filtreler