TB8钛合金超塑性变形的组织演变  

Microstructure Evolution of TB8 Alloy during Superplastic Deformation Process

作　　者：徐远刚[1] 董洪波[1] 袁大庆[1] 姜智勇[1] 周盛武[1] 

机构地区：[1]南昌航空大学航空制造工程学院

出　　处：《特种铸造及有色合金》2017年第6期668-671,共4页Special Casting & Nonferrous Alloys

基　　金：航空科学基金资助项目(2015ZE56011);江西省科学计划资助项目(20151BBE50042);南昌航空大学研究生创新基金资助项目(YC2015027)

摘　　要：研究了TB8合金在不同变形条件下的超塑性及其显微组织。结果表明,变形温度为690～840℃、应变速率为1.0×10^(-4)～1.0×10^(-3)s^(-1)时,TB8钛合金均具有超塑性。750℃、1.0×10^(-4)s^(-1)拉伸时,合金塑性最佳,伸长率为524.9%。变形过程中,变形软化和加工硬化相互抵消,表现为传统的超塑性变形稳态流动特征。变形温度、应变速率和变形程度对合金的超塑性、显微组织均有明显影响。应变速率越低,等轴β相晶粒尺寸越大。拉伸温度升高,β相晶粒尺寸增大,α相颗粒逐渐被溶解,β相饱和化,但仍能保持一定的等轴度。随着变形程度增大,β相晶界和基体弥散析出的α相越多,细小、弥散分布的α相可以抑制晶粒的过分长大,使合金塑性得到改善。The effects of different deformation conditions on the superplasticity of TB8 alloy and the microstructure evolution during deformation process were investigated. The results reveal that at 7204840℃ and 1.0×10-4 -1.0× 10-2 s-1 ,TB8 alloy exhibits the superplastic behavior. At 750℃ and 1.0× 10-4 s-1 , elongation of the TB8 alloy reaches 524.9%. During deformation process, the working hard- ening and the softening exhibits balance, and the alloy is characterized by the traditional steady-state su- perplastic flow behavior. Meanwhile, the deformation temperature,strain-rate and deformation rate have the significant effects on the microstructure. With decreasing in strain rate or increasing in tensile tem- perature, the size of the equiaxed β phase is increased. While with increasing in deformation tempera- ture, a phase is dissolved into the matrix gradually and β phase tends to be saturated, however, the grains still retain in equiaxed state to some extent. The a phase segregated dispersedly from the grain boundary and matrix of fl phase is increased with the deformation rate increase, which can inhibit the growth of grain size and improve the plasticity.

关 键 词：TB8钛合金 超塑性 显微组织 高温拉伸 

分 类 号：TG146.23[一般工业技术—材料科学与工程] TG135.3[金属学及工艺—金属材料]