Y. Choi
,
N.I. Baik
,
H.D. Cho
金属学报(英文版)
TiaAl-Nb-Mo composites were prepared by SHS using initial powder mixtures of Ti-Al-Nb-Mo and their corrosion and mechanical properties were studied to develop bio-and environmental materials. The composites reached 99.8% of theoretical densityafter the direct consolidation. The composites shows equiaxed primary α2 in a matrixof fine secondary α2 plates and ordered B2 (B0) forming a basket weave structure.The strain rate sensitivity (m = dlnσr/dlne) at 2% strain is 0.008. Corrosion po-tential and corrosion rate of the composites formed by SHS were -151.5mVSHE and5.72× 10-8A/cm2 for Ti3Al-10Nb-1.5Mo and -138.4m VSHE and 4.12×10-8cm-2 forTi3Al-12Nb-1.5Mo in a 50% NaOH-10%FeCl3 solution, respectively. Corrosion resis-tance decreased with niobium content in the composites and chloride content in theaqueous solution. Selective corrosion of α2 phase in a matrix occurred in the corrosionenvironment which suggests that the corrosion potential and rate changes are relatedto the niobium content and α2 phase in a matrix.
关键词:
Ti3Al alloy
,
null
,
null
,
null
H.J. Peng
,
Y.Q. Xie
,
null
,
null
金属学报(英文版)
On the basis of the framework of systematic science of alloys (SSA), the basic information such as states, volumes, and potential energies of characteristic atoms in hcp Ti-Al system have been determined. The average atomic state of the hcp Ti3Al compound consisting of ψ and ψ atoms is 0.75[Ar] (3dn)0.573 (3dc)2.1685 (4sc)0.972 (4sf)0.3093 + 0.25[Ne] (3sc)1.32 (3pc)1.19 (3sf + 3pf)0.49. The brittleness of the ordered hcp Ti3Al compound has been discussed considering the fundamental factors, which are atomic states, bond networks, potential energy wave planes, and the ratio xTi/xAl. The existence of more pc and more dc directional electrons in the hcp Ti3Al compound lead to considerable brittleness; From bond networks and potential energy wave planes, the hcp Ti3Al compound has poorer ductility than the pure hcp Ti metal and the pure fcc Al metal; The Al-rich hcp Ti3Al ordered type alloys have poorer ductility than the Ti-rich hcp Ti3Al ordered type alloys.
关键词:
Ti3Al alloy
,
null
,
null
李万青
,
魏红梅
,
何鹏
,
高丽娇
,
林铁松
,
李小强
,
赫兰春
材料工程
doi:10.11868/j.issn.1001-4381.2015.01.007
采用直接扩散连接Ti3Al和Ti2AlNb合金,研究了连接压力、连接温度、保温时间等工艺参数对接头界面组织形貌及性能的影响.利用扫描电镜、能谱分析和X射线衍射等方法观察分析了界面组织结构,并测试了接头的力学性能.结果表明:直接固相扩散连接接头的典型组织为Ti3Al/O相+α2相过渡层/富B2层/Ti2AlNb.当连接温度为1000℃,保温时间60min,连接压力为5MPa时获得的接头室温抗剪强度为635MPa,室温抗拉强度为795MPa,均断裂于Ti3Al母材一侧.经1000℃/60min热循环后Ti3 Al母材的抗拉强度下降至原始母材的76％.连接温度低于950℃或保温时间小于60min会导致未焊合等缺陷;温度高于1050℃或保温时间超过120min则导致Ti3Al发生相变.
关键词:
扩散连接
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Ti3Al合金
,
Ti2AlNb合金
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微观组织
,
性能
王震
,
曹磊
,
刘仁慈
,
刘冬
,
崔玉友
,
杨锐
金属学报
doi:10.3724/SP.J.1037.2013.00572
对两相区锻造的Ti3Al合金棒材分别在1020和1150℃保温30 min,以10,1.5和0.3℃/s速度冷至室温,研究了冷速对Ti3Al合金组织和拉伸性能的影响.结果表明,在1020℃固溶,冷速为10℃/s时,合金主要由B2相和α2相组成；降低冷速,基体中均匀析出针状α2/O相；冷速为0.3℃/s,等轴α2/O相体积分数增加,针状α2/O相粗化.随着冷速下降,合金的室温强度先升高后下降,塑性先降低后提高；600℃拉伸强度逐渐下降,塑性提高.在1150℃固溶,快速冷却时,合金主要由B2相构成,晶粒尺寸约为440μm;降低冷速,晶内均匀析出α2/O相,呈网篮状；冷速0.3℃/s时,基体中析出的α2/O相片层呈集束状.随着冷速下降,室温强度下降,而塑性先升高后降低；600℃拉伸强度先升高后降低,而塑性逐渐上升.结合组织分析表明,Ti3A1合金的强度取决于晶界和α2/O片层的尺寸,塑性受B2相体积分数以及α2/O相的分布及体积分数影响.冷速为1.5℃/s时,Ti3Al合金具有良好的综合力学性能.
关键词:
Ti3Al合金
,
冷却速率
,
显微组织
,
拉伸性能
付明杰
,
韩秀全
,
吴为
,
张建伟
金属学报
doi:10.11900/0412.1961.2014.00055
对Ti-23Al-17Nb合金在温度为940～1000℃,恒应变速率为1.7×103～5.5×10-5 s-1下的单向超塑拉伸变形行为进行了研究.结果表明,随着变形温度的升高,延伸率先增加后减小,在960℃,5.5×10-5s-1条件下获得最大延伸率为1447.5％.低应变速率条件下,Nb含量的增加使合金的加工硬化阶段增加.超塑变形有利于消除原始织构组织,对比原始组织,超塑拉伸过程中长条α2相发生了球化,并且其尺寸和含量随着温度升高逐渐减少,α2和B2相比例为50∶50时可达到最佳变形.利用Zener-Hollomn参数和Arrhenius方程建立了TAC-1B合金的峰值应力本构方程,其变形激活能Q=390.76 kJ/mol,为科学设计和有效控制Ti-23Al-17Nb合金的超塑成形工艺提供了理论依据.
关键词:
Ti3Al合金
,
超塑性
,
显微组织
,
本构方程
