低弹性模量亚稳β型Ti-38Nb合金的微观组织与力学行为  

Microstructure and Mechanical Behavior of β-Type Ti-38Nb Alloy with Low Modulus

作　　者：郭顺[1] 郑琦[1,2] 张俊松[1] 程晓农[1,2] 

机构地区：[1]江苏大学新材料研究院,江苏镇江212013 [2]江苏大学材料科学与工程学院,江苏镇江212013

出　　处：《稀有金属》2015年第9期769-774,共6页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51401088);江苏省自然科学基金项目(BK20140549);中国博士后科学基金面上项目(2014M561580)资助

摘　　要：报道了一种兼具低弹性模量和高强度的新型亚稳β型Ti-38Nb(%,质量分数)合金,并系统地研究了热-机械处理对合金微观组织及力学行为的影响。研究结果表明,Ti-38Nb合金经固溶处理后,由于合金中β稳定化元素含量不足,高温β相并没有完全保留至室温,合金中生成了大量的α″马氏体。此时,Ti-38Nb合金在较低的应力水平下(约207 MPa)便发生了马氏体变体的再取向和应力诱发马氏体相变,故无法满足生物医用材料对高强度的要求。经冷轧和673 K退火40 min后Ti-38Nb合金中引入了大量的位错和晶界,高密度的位错和晶界有效地抑制了ω相的析出和α″马氏体的产生。此时,β稳定化元素含量低的高温β相被稳定至室温,合金实现了低弹性模量(56 GPa)和高强度(拉伸强度1020 MPa)的良好匹配。因此,Ti-38Nb合金由于其低弹性模量和高强度特性有望在生物医用植入材料领域获得应用。A metastable β-type Ti-38Nb （% , mass fraction） alloy with a combination of low modulus and high strength was repor- ted, and the effect of thermo-rnechanical treatment on its microstmcture and mechanical behavior was also investigated systematically. It was found that in the solution-treated state, the high-temperature β phase cannot be completely retained at room temperature due to the occurrence of transformation from β to α＂ martensite caused by its low content of β-stabilizers （ i. e. Nb）. The solution-treated alloy exhibited low strength of 207 MPa due to stress-induced α＂ martensitic transformation and the reorientation of α＂ martensite. After a severe cold rolling and annealing, high-density of dislocations and grain boundaries existed in the Ti-38Nb alloy, resulting in the suppression of the α＂ martensitic transformation and the retarding of the precipitation of ω. As a result, overwhelming majority of β phases with low content of β-stabilizers were retained at room temperature. In such a case, an excellent combination of low elastic modulus （ - 56 GPa） and high ultimate tensile strength（ - 1020 MPa）was achieved in the binary Ti-38Nb alloy, which made it a high potential for biomedical applications.

关 键 词：亚稳Β钛合金 低弹性模量 Ω相 

分 类 号：TK91[动力工程及工程热物理]