新型亚稳β型Ti-30Nb-1Mo-4Sn合金时效过程中ω相与α相的竞争  

Competition Behavior of ω and α Phase during Aging of Novel Metastable β-Type Ti-30Nb-1Mo-4Sn Alloy

作　　者：田恬[1] 郑琦[1] 商铫 侯艳嫔 程晓农[1] 郭顺[1] 

机构地区：[1]江苏大学材料科学与工程学院

出　　处：《稀有金属》2018年第1期101-105,共5页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51401008,51601069);江苏省自然科学基金项目(BK20140549);中国博士后科学基金特别项目(2016T90424)资助

摘　　要：对一种新型亚稳β型Ti-30Nb-1Mo-4Sn（％，质量分数）合金时效过程中ω相与α相相的竞争行为进行了系统研究。研究表明，Ti-30Nb-1Mo-4Sn合金经固溶处理或冷轧处理后，合金的相组成均为ω相与α相马氏体。固溶态和冷轧态Ti-30Nb-1Mo-4Sn合金经相同的时效处理（即573K时效2h）后，析出产物分别为等温ω相与α相。这主要是由于冷轧后合金内部含有大量位错和品界，这些位错和晶界在后续时效过程中抑制了等温β相的析出，同时为a相的异质形核提供了条件，促进了“相的析出。这一发现为亚稳p钛合金时效过程中ω相与α相之间的竞争提供了直接的证据。此外，上述研究结果也清楚地表明，通过对亚稳口钛合金进行冷轧预处理，可以在后续时效过程中抑制脆性ω相析出的同时在合金中获得对力学性能有利的细小a强化相，这无疑对研发低模量和高强度兼备的新型β钛合金具有重要的意义。The competition behavior of to and a phase during the aging process of a novel rnetastable β-type Ti-30Nb-1Mo-4Sn （ % , mass fraction） alloy was investigated systematically. It was found that the alloy consisted of β phase and ω martensite both in solution- treated and cold-rolled states. After aging at 573 K for 2 h, the metastable to phase or equilibrium ω phase precipitated in solution-trea- ted and cold rolled alloy, respectively. This was attributed to high-density dislocations and grain boundaries introduced by cold rolling, which suppressed the formation of to phase and promoted the formation of a phase. The results provided direct evidence for the competi- tion behavior of aged β-type Ti alloys between metastable to and equilibrium a phases. In addition, the results provided a thermo-me- chanieal approach to inhibit deleterious to phase formation and assist fine a phase precipitation, which were beneficial for the enhance- ment of mechanical properties. These results were of important significance to develop advanced β-type Ti alloy with ultralow Young＇s modulus and high strength.

关 键 词：亚稳Β钛合金 固态相变 Ω相 Α相 

分 类 号：TG146.2[一般工业技术—材料科学与工程]