TA15钛合金在相变点附近的热变形机制及组织演化  

Thermal Deformation Mechanism and Microstructure Evolution of TA15 Titanium Alloy near the Phase Transition Point

作　　者：姚彭彭 李萍[1] 李成铭[1] 薛传妹[1] 甘国强[1] 薛克敏[1] 

机构地区：[1]合肥工业大学材料科学与工程学院,安徽合肥230009

出　　处：《稀有金属与硬质合金》2015年第1期46-52,共7页Rare Metals and Cemented Carbides

基　　金：国家自然科学基金资助项目(51175137);安徽省自然科学基金资助项目(1308085JGD02)

摘　　要：采用Gleeble—3500型热模拟试验机对TA15钛合金进行等温压缩试验,应变速率为1~0.01s-1、变形温度为900~1 050℃。结果表明:TA15钛合金在相变点附近的热压缩流变行为可采用含有Z参数的双曲正弦函数形式的本构方程来描述;在试验参数范围内,当变形温度和应变速率逐渐提高时,TA15钛合金内部显微组织和热变形机制发生改变,导致变形激活能先升高后降低;结合热加工图和热变形后的显微组织分析可知,在两相区上部(变形温度950℃左右)以较低的应变速率(0.1~0.01s-1)进行热变形时,由于完全动态再结晶的发生,材料具有较高的耗散效率,获得了晶粒细小且分布均匀的显微组织。Isothermal compression experiments of TA15 titanium alloy were conducted on Gleeble-3500 thermal simulator with strain rate of 1~0.01s-1 and deformation temperature of 900~1 050 ℃.The results show that thermal deformation behavior of TA15 titanium alloy near the phase transition point can be described by a constitutive equation in hyperbolic sine function form including Zparameter.Within the experimental parameter range,with deformation temperature and strain rate gradually increasing,microstructure and thermal deformation mechanism of TA15 titanium alloy change,resulting in deformation activation energy increased firstly and then decreased.Thermal processing map and deformation microstructure analysis show that when thermal deformation happens in the upper part of two-phase region(about 950℃)at a lower strain rate(0.1~0.01s-1),the energy dissipation efficiency of the alloy is higher and its microstructure has uniformly distributed fine grains due to complete dynamic recrystallization.

关 键 词：TA15钛合金 热变形机制 组织演化 本构方程 激活能 加工图 

分 类 号：TG146.23[一般工业技术—材料科学与工程]