高压热处理对TC6钛合金α→β相变动力学的影响  

Phase Transformation Kinetics of α→β in TC6 Titanium Alloy with High Pressure Heat Treatment

作　　者：赵军 谌岩[3] 文全兴[1] 张晗 李鑫 孙欢迎 Zhao Jun Chen Yan Wen Quanxing Zhang Han Li Xin Sun Huanying(School of Materials and Engineering, North China Institute of Aerospace Engineering, Langfang 065000, China College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China)

机构地区：[1]北华航天工业学院材料工程学院,河北廊坊065000 [2]燕山大学亚稳材料制备技术与科学国家重点实验室,河北秦皇岛066004 [3]燕山大学环境与化学工程学院,河北秦皇岛066004

出　　处：《稀有金属》2017年第10期1087-1092,共6页Chinese Journal of Rare Metals

基　　金：河北省自然科学基金项目(E2013409002;E2014203135);河北省教育厅科研基金项目(Z2015178);河北省普通高等学校青年拔尖人才计划项目(BJ2014001);燕山大学青年教师自主研究计划课题项目(14LGA015);廊坊市科技支撑计划项目(2014011047;2016011081);北华航天工业学院科研基金重点项目(ZD-2016-03)资助

摘　　要：针对高压热处理能改善(α+β)钛合金组织的问题,对TC6钛合金进行5 GPa压力,1000℃保温20 min的高压热处理,利用差示扫描量热仪(DSC)测试了高压热处理前后TC6钛合金在不同升温速率下的α→β相变温度和转变时间,根据Deloy方程和Ozawa方程分别计算其相变激活能和Avrami指数,并利用光学显微镜(OM)和透射电镜(TEM)对高压热处理前后TC6钛合金的组织进行观察,探讨了高压热处理对TC6钛合金中α→β相变动力学的影响。结果表明:5 GPa压力热处理能降低TC6钛合金的α→β相变温度,缩短相变时间,增大相变激活能。当合金以20℃·min^(-1)升温时,5 GPa压力热处理能使α→β相变起始温度和相变结束温度较5 GPa压力处理前分别降低了4.88和8.71℃,相变时间也减少了0.2 min。当相变体积分数为50%时,5 GPa压力处理后合金的α→β相变激活能较5 GPa压力处理前增大了155.29k J·mol^(-1),但高压热处理对α→β相变机制影响不大。其原因主要是高压热处理能增大TC6钛合金组织中的晶界密度和位错密度。As high pressure heat treatment could improve the microstructure of（ α ＋ β） titanium alloy,TC6 titanium alloy was heat treated at 5 GPa and 1000 ℃ for 20 min. The α→β phase transformation temperature and time in TC6 titanium alloy before and after high pressure treatment at different heating rates were measured by differential scanning calorimeter（ DSC）,the phase transition activation energy and Avrami exponent were calculated according to Deloy and Ozawa equation,respectively. The microstructure was observed by optical microscope（ OM） and transmission electronic microscope（ TEM）,and the effect of high pressure heat treatment on phase transformation kinetics of α→β in TC6 titanium alloy was studied. The results showed that 5 GPa pressure treatment could reduce the temperature and time for α→β phase transformation,and enhance the phase transformation activation energy. When the sample was heated at 20 ℃·min^（-1）,initial temperature,ending temperature and time of α→β phase transformation in TC6 titanium alloy after high pressure treatment were decreased by 4. 88,8. 71 ℃ and 0. 2 min,respectively. When the phase transformation volume fraction was 50%,the phase transformation activation energy was increased by 155. 29 k J·mol（-1）,compared with that without high pressure treatment,but high pressure heat treatment had little effect on its phase transition mechanism. The main reason was that the high pressure heat treatment could increase grain boundary density and dislocation density in titanium alloy.

关 键 词：TC6钛合金 高压热处理 相变动力学 

分 类 号：TG166.5[金属学及工艺—热处理]