Ti60合金的热变形行为及加工工艺参数优化  

Hot Deformation Behavior and Processing Parameter Optimization of Ti60 Alloy

作　　者：王天祥 鲁世强[2] 王克鲁[2] 欧阳德来[2] 姚泉 Wang Tianxiang;Lu Shiqiang;Wang Kelu;Ouyang Delai;Yao Quan(Nanchang Hangkong University,Nanchang 330063,China;School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]南昌航空大学航空制造工程学院,江西南昌330063 [2]南昌航空大学,江西南昌330063

出　　处：《稀有金属材料与工程》2020年第10期3552-3561,共10页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51964034,51761029);江西省研究生创新基金(YC2018-S365)。

摘　　要：在变形温度600~950℃,应变速率0.001~10s^-1条件下,采用Thermecmaster-Z型热加工模拟试验机对Ti60合金进行等温恒应变速率压缩实验。通过分析流动应力行为,计算应变速率敏感指数m和应变硬化指数n,并综合考虑加工图和变形微观组织来研究该合金的热变形行为,得到优化的加工工艺参数范围。研究结果表明,Ti60合金的流动应力-应变曲线在不同工艺参数条件下分别呈现流动稳态型和流动软化型。应变速率敏感指数m随着变形温度升高和应变速率降低而增大。应变硬化指数n随着变形温度升高而减小;随着应变速率的增加在低应变速率(0.001~0.1s^-1)区间增大,在高应变速率(1~10s^-1)区间减小;随着应变的增加在高温段(800~950℃)的低应变速率(0.001~0.1s^-1)区间较缓慢地减小,在高温段(800~950℃)的高应变速率(1~10s^-1)区间以及低温段(600~750℃)的所有应变速率(0.001~10s^-1)区间较明显地减小。Ti60合金存在2个功率耗散效率峰值区域,其对应的热力学参数窗口分别为温度725~875℃,应变速率≤0.003s^-1和温度875~938℃,应变速率≤0.04s^-1。从流动应力行为、应变速率敏感指数m、应变硬化指数n以及加工图综合考虑,Ti60合金的最佳热加工工艺参数为:温度800~875℃,应变速率0.001~0.003s^-1,或温度875~938℃,应变速率0.001~0.04s^-1。The isothermal compression experiment of Ti60 alloy was conducted on the Thermecmaster-Z thermal simulator at deformation temperature of 600~950℃,strain rate of 0.001~10s^-1.The hot deformation behavior of Ti60 alloy was investigated by analyzing the flow stress behavior,calculating the strain rate sensitive exponent m and strain hardening exponent n,along with the processing map and deformation microstructure,to optimize processing parameters.The results show that the flow stress-strain curve of Ti60 alloy presents flow steady state and flow softening under different processing parameters.The strain rate sensitivity exponent m increases with the increase of deformation temperature and decrease of strain rate.The strain hardening exponent n decreases with the increase of deformation temperature.With the increase of strain rate,n increases at the low strain rate(0.001~0.1s^-1)and decreases at the high strain rate(1~10s^-1).With the increase of strain,n decreases slowly at the low strain rate(0.001~0.1s^-1)of the high temperature section(800~950℃),while it decreases significantly at high strain rate(1~10s^-1)of high temperature section(800~950℃),or at all the strain rates(0.001~10s^-1)of the low temperature section(600~750℃).Ti60 alloy has two peak power dissipation efficiency regions,whose corresponding processing parameter windows are:temperature 725~875℃,strain rate≤0.003s^-1 and temperature 875~938℃,strain rate≤0.04s^-1.Considering the flow stress behavior,strain rate sensitivity exponent m,strain hardening exponent n and processing map,the optimal thermal processing parameters of Ti60 alloy are temperature 800~875℃,strain rate 0.001~0.003s^-1,or temperature 875~938℃,strain rate 0.001~0.04s^-1.

关 键 词：Ti60合金 流动应力行为 应变速率敏感指数 应变硬化指数 加工图 

分 类 号：TG146.23[一般工业技术—材料科学与工程]