固溶和时效温度对TC6钛合金显微组织与力学性能的影响  

Effects of Solution-Treatment and Aging Temperature on Microstructure and Mechanical Properties of TC6 Titanium Alloy

作　　者：雷晓飞 董利民[1] 张志强[1] 胡明[1] 李炎州 杨锐[1] Lei Xiaofei;Dong Limin;Zhang Zhiqiang;Hu Ming;Li Yanzhou;Yang Rui(Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]中国科学院金属研究所,辽宁沈阳110016

出　　处：《稀有金属材料与工程》2020年第3期1038-1044,共7页Rare Metal Materials and Engineering

摘　　要：研究了不同温度的固溶和时效工艺对TC6钛合金显微组织和性能的影响。结果表明:800~840℃固溶后,合金由初生α相和亚稳β相组成,两相随着温度升高而长大,合金强度和塑性略有上升;880℃固溶后,亚稳β相依然保留到室温,然而在拉伸过程中出现应力诱变斜方马氏体α″相,导致双屈服现象;920~960℃固溶后,初生α相减少,大量的细针状斜方马氏体α″相在亚稳β相上析出,强度上升塑性下降;当超过β相变点固溶后,主要由粗大针状六方马氏体α?相组成,强度下降同时拉伸为脆性断裂。对于固溶样品经过不同温度时效处理,主要变化过程是亚稳β相分解为次生α相及其长大,300℃时效后,相比固溶态强度上升但塑性下降,亚稳β相中弥散析出次生α相及少量的ω相;当时效温度升高到400℃,强度继续上升接近最大值但塑性最差;500℃时效后,强度最高然而合金元素充分扩散,塑性得到提升;550℃时效后,强度有所下降但塑性明显提升,此时具有较佳的强塑性匹配;600~700℃时效后,初生α相聚集长大并且含量增加,次生α相在β基体上析出且逐渐长大为层片状,强度下降塑性进一步提升。Effects of solution-treatment and aging temperature on microstructure and mechanical properties of TC6 titanium alloy were investigated. The results show that when specimens are solution-treated is at 800~840 °C, primary α and metastable β phases are form and they grow up with the increase of the temperature, which result in the slight increase of the strength and ductility. The metastable β phase is also retained after solution-treatment at 880 °C though its stability is weakened, while at this moment double yield phenomenon is observed, which is attributed to stress-induced α″ orthorhombic martensite in the metastable β phase. When specimens are solution-treated at 920~960 °C, primary α phase dissolves, and a large amount of fine acicular α″ orthorhombic martensite precipitate from the metastable β phase;the strength increases and the ductility decreases,. The alloy is almost composed of coarse α? hexagonal martensite after solution treatment above the β transus, which lead to the decrease in strength and the brittle fracture during tensile test. In terms of different aging temperatures for solution-treated specimens(880 °C/1.5 h/WQ), the main microstructural changes are the precipitation of secondary α phase from the metastable β phase and its growth. Compared with solution-treated specimens, the specimens aged at 300 °C exhibit higher strength and lower ductility, and it can be seen that some secondary α phase and ω phase have precipitated from the β matrix. As the aging temperature increases to 400 °C, the maximum strength as well as minimum ductility is obtained. The specimens aged at 500 °C maintain the maximum strength, while the ductility is improved due to the sufficient diffusion of alloying elements. When the specimens are aged at 550 °C, they possess the optimum balance of strength and ductility. The primary α phase gradually gathers to grow up and the lamellar secondary α phase apparently disperses in the β matrix after aging at 600~700 °C, which lead to the decrease i

关 键 词：TC6钛合金 固溶和时效 显微组织 力学性能 

分 类 号：TG146.23[一般工业技术—材料科学与工程]