MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
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2020
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IF 4.652
Hailiang Li,Dechang Jia,Zhihua Yang,Xingqi Liao,Haize Jin,Delong Cai,Yu Zhou
Post heat treatment has been considered as an essential process to relieve residual stress, tailor the microstructure and obtain desired mechanical properties of the parts manufactured by selective laser melting (SLM) technology. The present work comparatively investigated the effect of heat treatment on microstructure evolution and mechanical properties of the SLM-fabricated Ti–6Al–4V alloy (Ti64) and 2 vol% TiB/Ti–6Al–4V titanium matrix composite (TMC). Microstructure analysis indicated that the as-built and heat treated TMC samples showed profoundly different microstructures compared to that of Ti64 samples . With heat treatment temperature increasing, the dominant acicular α′ martensite of Ti64 was decomposed into fine (α+β) lamella and microstructure coarsening occurred. A finer (α+β) dual-phase matrix microstructure, compared to that of Ti64, was achieved for TMC samples when heat treatment temperature exceeded 850 °C. The densely dispersed clusters of parallel nanoscale TiB precipitates of the TMC grew into individually separate TiB whiskers with larger nanoscale and sub-microscale size through a stacking up process of (100) planes based on an Ostwald ripening process. Mechanical testing results showed that the hardness and yield strength values of TMC samples before and after heat treatment were all higher than that of the Ti64 samples. A superior comprehensive mechanical performance with relatively high yield strength (1345 MPa) and significantly improved fracture strain from 17.6% to 31.3% was achieved for the TMC sample after heat treatment at 850 °C.
研究领域:
材料科学
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金属加工工程
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2019
·Vol. 6
·期 10
·105316
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IF 1.449
Ruoyu Liu,Chuanbing Huang,Lingzhong Du,Hao Lan,Shige Fang,Weigang Zhang
Aluminium/polyimide (Al/PI) powders were prepared via in situ. Al/PI composites were fabricated by hot pressing technology at 723 K for 30 min under Ar. The microstructure, thermal stability and tribological properties of Al/PI composites were investigated. SEM images showed that Al particles were wrapped in the composite with no gap. According to the TG analysis, 15Al/PI composite showed excellent thermal stability up to 773 K. Meanwhile, 15Al/PI composites exhibited excellent tribological behaviour at high temperature, especially at 773 K. The friction coefficient of 15Al/PI composite at 773 K was about 0.28 which was lower than that of pure PI (about 0.41). The wear rate of 15Al/PI composite at 773 K was about 65 × 10−5 mm3 Nm−1. The tribological properties of Al/PI composites was improved at high temperature. In the process of sliding tests, Al particles were transferred to the Ti-6Al-4V alloy's surface and PI particles were pressed on the composite's surface. The transfer of Al can protect Ti-6Al-4V alloy from wear and reduce the friction coefficient during the sliding test.
研究领域:
材料科学
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摩擦学
✓ 已验证
DOI
高影响因子
Metals
·
2023
·Vol. 13
·期 2
·264
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IF 2.9
Dongdong He,Hui Wang,Weidong Huang,Xinxi Chen,Guofu Lian,Yu Wang
In this study, TiB + La2O3/Ti-6Al-4V composites were successfully prepared by in situ reaction using selective laser melting technology. The effect of LaB6content on the fabrication quality, microstructure evolution and mechanical properties of the composite samples was investigated. The results show that the relative density of the sample gradually decreased from 98.56% to 96.57% as LaB6content increased from 0 wt% to 3 wt%. With increasing LaB6content, TiB precipitates gradually aggregated and grew from a discrete needle-like structure to a dendritic structure, before eventually developing a cell-like structure. The dislocations piled up around the TiB and La2O3reinforcements, which impeded the motion of the dislocations and led to the enhancement of the tensile strength of the samples. Different from the addition of a single reinforcement due to the combined strengthening effect of the micrometer-scale and nanoscale reinforcements, the strength of the samples was increased significantly. The Ti-6Al-4V sample with 3 wt% LaB6addition showed the most significant strengthening effect. Compared to the pure Ti-6Al-4V sample, the 3 wt% LaB6addition sample gained a 35.71% increase in hardness and a 14.5% increase in tensile strength. Additionally, wear volume was reduced by 47.5%. The results revealed that the addition of LaB6was a potential way to improve the mechanical performance of the titanium alloys in the additive manufacturing process.
研究领域:
材料科学
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机械工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2022
·
IF 6.371
Mingyuan Zhang,Taotao Cai,Weiliang Lu,Shili Zheng,Ying Zhang,Yi Zhang
Given the high cost of fabricating the Ti-6Al-4V alloy powder by the traditional hydriding-dehydriding and atomization methods, a novel sintering-deoxygenation process was proposed and studied in this research. With the help of the developed deoxygenation treatment, value-added raw materials such as Ti sponge can be substituted by low-cost and low-grade materials with high oxygen content. In addition, sintering in a solid state saves a significant amount of processing energy compared to alloying above the melting point of Ti in the conventional alloy production process. This paper prepared six sintering precursors with different initial compositions and oxygen contents using the low-valued raw materials of crude titanium, crude vanadium, V 2 O 3 , Al powder, and Al 2 O 3 powder. These precursors' sintering performances on shrinkage, phase composition, microstructure, and porosity were investigated. The results show that the sintering shrinkage is positively correlated with the sintering temperature and holding time and is also affected by the raw materials. The pellet made by mixed crude titanium and AlV master alloy showed the largest shrinkage and the densest bulk. The various combinations of the raw materials led to the changes in the oxygen contents in the precursors, the alpha-beta phase ratio, and the shift of the diffraction peaks of the α-phase. The dissolving of the AlV master alloy and the formation of the Ti 3 Al intermediate phase took place during sintering due to diffusion. Sintering at 900–1000 °C is critical for elemental diffusion and densification, and sintering at higher temperatures is decisive for microstructure homogenization and further densification. Using the hydrogen-assisted Mg deoxygenation method, all the sintered samples could be treated to an oxygen level of around 0.4 wt% regardless of oxygen content in precursors. The contents of Ti, Al, V, and Fe in the obtained Ti-6Al-4V powders met the requirements of GB/T 34486-2017. This research has demonstrated the feasibility of fabricating Ti-6Al-4V alloy powder by the novel sintering-deoxygenation process.
研究领域:
材料科学
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冶金工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Central South University
·
2022
·Vol. 29
·期 6
·1811-1822
·
IF 2.392
Dong Zhao-wang,Xia Yang,Guo Xue-yi,Liu Han-ning,Liu Pei-dong
Ti-6Al-4V alloy powder was prepared through a two-step reduction of a mixture of TiO 2 , V 2 O 5 and Al 2 O 3 in this study. The oxide mixture was first reduced by Mg in MgCl 2 at 750 °C in argon, where oxygen was reduced to 2.47 wt% from 40.02 wt%. The oxygen content in the final powder was eventually reduced to an extremely low level (0.055 wt%) using calcium at 900 °C in argon, and the final powder had the composition of 90.12 wt% Ti, 5.57 wt% Al, and 3.87 wt% V, which meets the standard specification of Ti-6Al-4V (ASTM F1108-09). Between the two reductions, a heat treatment step was designed to help controlling the specific surface area and particle size. The effect of the heat treatment temperature on the morphology, and composition uniformity of the powder was investigated in detail. Heat treatment above 1300 °C attributed to a dense powder with a controlled specific surface area. Thermodynamic modeling and experimental results indicated that only α -Ti enriched with Al and β-Ti enriched with V exist in the final powder, and other possible phases including Al-Mg and Al-V were excluded. This study also offers a triple-step thermochemical process for producing high-purity Ti-based alloy powder.
研究领域:
材料科学
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冶金工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2022
·
IF 6.364
Qin Sun,Ludong Yang,Wanchun Yang,Hongjun Ji,Mingyu Li,Yufeng Li
Ceramics and metal joinings have been widely employed in aerospace, dental implants , and the electronic packaging industry for fabricating multifunctional components. In this study, the 35Bi 2 O 3 -50B 2 O 3 -15ZnO (mol.%) glass has been employed for joining the ZrO 2 ceramic and Ti-6Al-4V alloy. The effect of brazing temperature on the microstructure evolution, mechanical properties , and bonding mechanism of brazed joints has been analyzed. The microstructure of the ZrO 2 /glass/Ti-6Al-4V joints and the content of Bi 4 B 2 O 9 , Bi 2 O 3 and Bi 24 B 2 O 39 precipitated crystals in glass were found to be dependent on the brazing temperature. The reaction product of Bi 4 Ti 3 O 12 was identified in the glass/Ti-6Al-4V interface because of the chemical reaction between the oxidized layer of Ti-6Al-4V alloy and glass. A maximum shear strength as high as 48.8 ± 5.2 MPa was obtained. Our work, thus, demonstrates that the 35Bi 2 O 3 -50B 2 O 3 -15ZnO glass is an effective bonding material for joining ZrO 2 ceramic and Ti-6Al-4V alloy under low temperature in an ambient atmosphere.
研究领域:
材料科学
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焊接工程
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2019
·Vol. 12
·期 19
·3097
·
IF 2.972
Hailiang Du,Ning Tan,Li Fan,Jiajie Zhuang,Zhichao Qiu,Yanhua Lei
The diffusion coatings were deposited on commercially pure Ti and Ti-6Al-4V alloy at up to 1000 °C for up to 10 h using the pack cementation method. The pack powders consisted of 4 wt% Al (Al reservoir) and 4 wt% NH4Cl (activator) which were balanced with Al2O3(inert filler). The growth kinetics of coatings were gravimetrically measured by a high precision balance. The aluminised specimens were characterised by means of scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). At the early stages of deposition, a TiO2(rutile) scale, other than aluminide coating, was developed on both materials at <900 °C. As the experimental temperature arose above 900 °C, the rutile layer became unstable and reduced to the low oxidation state of Ti oxides. When the temperature increased to 1000 °C, the TiO2scale dissociated almost completely and the aluminide coating began to develop. After a triple-layered coating was generated, the coating growth was governed by the outward migration of Ti species from the substrates and obeyed the parabolic law. The coating formed consisted of an outer layer of Al3Ti, a mid-layer of Al2Ti and an inner layer of AlTi. The outer layer of Al3Ti dominated the thickness of the aluminide coating.Keywords:diffusion coating;aluminide;pack cementation;Ti;Ti-6Al-4V;mechanism
研究领域:
材料科学
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表面工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2017
·
IF 3.133
Chao Cai,Bo Song,Chunlei Qiu,Lifan Li,Pengju Xue,Qingsong Wei,Jianxin Zhou,Hai Nan,Hongxia Chen,Yusheng Shi
In this study, titanium borides reinforced Ti-6Al-4V composites have been successfully prepared by hot isostatic pressing (HIPing). The microstructure of the as-fabricated samples was investigated using X-ray diffraction technique, secondary electron microscopy and electron backscatter diffraction and the mechanical properties evaluated through micro-hardness and wear resistance measurements together with nano-indentation. It was found that during HIPing the additive particles TiB 2 have transformed into TiB needles which tend to decorate at prior particle boundaries of the consolidated powder particles to form a network structure. Under the same HIPing condition, the needles became increasingly coarser and agglomerated with increased addition of TiB 2 . The micro-hardness of the synthesized materials increased with increased volume fraction of TiB. Nano-indentation measurement demonstrates that the TiB network structure shows much higher nanohardness than the surrounding matrix regions. The friction coefficient of the synthesized composites decreased continuously with increased volume fraction of TiB, indicating improved wear resistance. High resolution transmission electron microscopy analysis on wear debris revealed the formation of a series of oxides suggesting that chemical reaction between alloy elements and oxygen in air may have happened. It is thus believed that the wearing of the current samples is a result of both friction and chemical reaction.
研究领域:
材料科学
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工程学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE FORUM
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2017
·
IF 0
Zhao Bing Cai,Xue Jia Pang,Xiu Fang Cui,Xin Wen,Zhe Liu,Mei Ling Dong,Yang Li,Guo Jin
In order to improve the surface properties of Ti-6Al-4V, high-entropy alloy coatings were prepared by in-situ laser cladding on the surface of Ti-6Al-4V substrate. The microstructure, micro-hardness, corrosion resistance and wear resistance were investigated. The results showed that the high-entropy alloy coating was composed of BCC high-entropy alloy phase, α-Ti phase and (Ni, Co)Ti2 phase. The micro-hardness of the high-entropy alloy coatings is much higher than that of Ti-6Al-4V substrate. The coating also has a better corrosion resistance than Ti-6Al-4V substrate, even superior to 304SS in 3.5wt.% NaCl solution at room temperature. Compared with Ti-6Al-4V substrate, the high-entropy alloy coating has a greater wear resistance with the wear mass loss decreased 28.2% and 23.1%, respectively. Wear patterns of Ti-6Al-4V substrate and high-entropy alloy coatings are the coexistence of adhesive wear and abrasive wear, but the wear degree of high-entropy alloy coatings is lower.
研究领域:
材料科学
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表面工程
✓ 已验证
产品关联
DOI
POWDER TECHNOLOGY
·
2018
·
IF 3.23
Chao Cai,Chrupcala Radoslaw,Jinliang Zhang,Qian Yan,Shifeng Wen,Bo Song,Yusheng Shi
In this study, the in-situ synthesized TiB/Ti-6Al-4Vceramic-matrix nanocomposites with greatly enhanced hardness and wear resistant property have been prepared via selective laser melting (SLM) using a simple mixture of microsized Ti-6Al-4V and TiB 2 powders. In order to provide a valuable reference for fabricating TiB/Ti-6Al-4V parts with metallographic features, effects of reinforcement content on microstructure and mechanical properties have been systematically investigated. It is found that during SLM process, the additive particles TiB 2 are totally transformed into need-like nanoscaled TiB phase, and the microstructure of composites is composed of mutual parallel strips architecture with TiB rich in some regions but lean in the other regions. The SLM-producedTiB/Ti-6Al-4 V composites exhibit superior nanohardness of 6.0 GPa, which is much higher than its traditional sintering counterpart. Moreover, the in-site synthesized TiB reinforcement can remarkably improve in the wear resistance properties, the wear loss of TiB-free sample is approximately 2 times than that of the sample with 3 wt% TiB 2 .
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHARACTERIZATION
·
2016
·
IF 2.383
Zhaobing Cai,Guo Jin,Xiufang Cui,Zhe Liu,Wei Zheng,Yang Li,Liquan Wang
Ni-Cr-Co-Ti-V-Al high-entropy alloy coating on Ti-6Al-4V was synthesized by laser surface alloying. The coating is composed of a B2 matrix and (Co, Ni)Ti 2 compounds with few β-Ti phases. Focused ion beam technique was utilized to prepare TEM sample and TEM observations agree well with XRD and SEM results. The formation of HEA phases is due to high temperature and rapid cooling rate during laser surface alloying. The thermodynamic parameters, ΔH mix , ΔS mix and δ as well as Δχ, should be used to predict the formation of the BCC solid solution, but they are not the strict criteria. Especially when Δχ reaches a high value (≥ 10%), BCC HEA will be partially decomposed, leading to the formation of (Co, Ni)Ti 2 compound phases.
研究领域:
材料科学
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
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2019
·
IF 6.864
Chao Cai,Shan He,Lifan Li,Qing Teng,Bo Song,Chunze Yan,Qingsong Wei,Yusheng Shi
In-situ synthesized titanium borides reinforced Ti-6Al-4V composites with a tailored reinforcement architecture were successfully prepared by hot isostatic pressing (HIP) starting from a TiB 2 /Ti-6Al-4V powder system. The microstructure of the composite samples was investigated using X-ray diffraction (XRD) technique and scanning electron microscopy (SEM), and the mechanical properties were evaluated through room and high temperature tensile testing . It is found that during HIP the additive particles TiB 2 have totally transformed into TiB needles, which tend to decorate at prior particle boundaries of the consolidated powder particles to form a network structure. With increasing TiB 2 addition from 3 wt.% to 8 wt.%, the microstructural feature of the TiB network structure experiences the variations of discontinuous TiB reinforcement → quasi-continuous TiB reinforcement → continuous TiB reinforcement. The room temperature tensile properties of the composites are improved with increasing addition of TiB 2 from 3 wt.% to 5 wt.%, but the tensile strength of the sample with 8 wt.% TiB 2 drastically decreases. As to the high temperature properties, the titanium boride reinforced Ti-6Al-4V alloy composites can be an increased maximum service temperature by over 200 °C while retaining the same tensile strength accompanied with a suitable elongation. The strengthening mechanism is mainly attributed to the load-bearing transformation, grain refinement and dispersion strengthening.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）