热机械加工Ti-6Al-4V钛合金的流变行为和显微组织演变  

Rheological behavior and microstructure evolution on Ti-6Al-4V titanium alloy by hot machining

作　　者：王立颖[1] 杨友[2] 刘春兰 Wang Liying;Yang You;Liu Chunlan(School of Mechanical Engineering,Jilin Railway Technology College,Jilin 132200,China;School of Material Science and Engineering,Changchun University of Technology,Changchun 130012,China;School of Materials Science and Engineering,Harbin University of Technology,Harbin 150001,China)

机构地区：[1]吉林铁道职业技术学院机械工程学院,吉林吉林132200 [2]长春工业大学材料科学与工程学院,吉林长春130012 [3]哈尔滨工业大学材料科学与工程学院,黑龙江哈尔滨150001

出　　处：《锻压技术》2020年第12期183-190,共8页Forging & Stamping Technology

基　　金：吉林省青年科研基金(20190520037JH);吉林省教育厅“十三五”科研基金(2019115)。

摘　　要：采用Gleeble-3800型热模拟试验机对Ti-6Al-4V钛合金进行了变形温度为900~1100℃、应变速率为0.07~70 s-1的热压剪处理,对比分析了不同热机械加工参数下的流变行为和微观组织演变规律。结果表明:在相同的应变速率下,随着变形温度从900℃上升至1100℃,对Ti-6Al-4V钛合金的峰值应力呈现逐渐减小的趋势;而在相同变形温度下,应变速率越高则峰值应力越大。950℃/70 s-1变形条件下的应力-应变曲线中未出现明显的不连续屈服现象,但可见流变波动现象;而变形温度为1050和1100℃、应变速率为0.07和70 s-1时,Ti-6Al-4V钛合金的应力-应变曲线中均存在不连续屈服的现象。当变形温度为950℃时,应变速率敏感系数m随着应变速率的增加而增大,而其他变形温度下,m随着应变速率的增加而减小,这主要是由于Ti-6Al-4V钛合金在950℃/70 s-1热变形过程中发生了动态相变,而使得部分等轴α相向板条α相转变,而单相区热变形时主要发生了α相向β相的转变以及动态回复和动态再结晶,从而出现软化现象。The Ti-6Al-4V titanium alloy was treated by hot shear-compression in thermal simulator Gleeble-3800 with the deformation temperature of 900-1100℃and the strain rate of 0.07-70 s-1,the rheological behavior and microstructure evolution of Ti-6Al-4V titanium alloy under different processing parameters of hot machining were compared and analyzed.The results show that at the same strain rate,with the increasing of deformation temperature from 900℃to 1100℃,the peak stress of Ti-6Al-4V titanium alloy decreases gradually,while at the same deformation temperature,the higher the strain rate is,the greater the peak stress is.However,there is no obvious‘discontinuous yield’phenomenon in the stress-strain curve under 950℃/70 s-1 deformation condition,but‘rheological fluctuation’phenomenon can be seen.When the deformation temperature is 1050 and 1100℃and the strain rate is 0.07 and 70 s-1,there is‘discontinuous yield’phenomenon in the strain-strain curve of Ti-6Al-4V titanium alloy.Furthermore,when the deformation temperature is 950℃,the strain rate sensitive coefficient m increases with the increasing of strain rate,while at other deformation temperatures,m decreases with the increasing of strain rate.This is mainly due to the dynamic transformation of Ti-6Al-4V titanium alloy during the thermal deformation process at 950℃/70 s-1,which causes the partial equiaxedɑphase to transform into lathɑphase,and the transition fromɑphase toβphase,dynamic recovery and dynamic recrystallization occur during the thermal deformation of single-phase region which resulting in softening.

关 键 词：TI-6AL-4V钛合金 热压剪 流变行为 软化机制 显微组织 

分 类 号：TG146.2[一般工业技术—材料科学与工程]