TC4-DT钛合金热变形机制及加工图  

Hot Deformation Mechanism and Processing Map of TC4-DT Titanium Alloy

作　　者：雷文光[1,2] 韩栋[2] 张永强[2] 毛小南[2] 李金山[1] 杨冠军[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072 [2]西北有色金属研究院,陕西西安710016

出　　处：《钛工业进展》2015年第1期20-25,共6页Titanium Industry Progress

基　　金：国家自然科学基金青年基金项目(51201138)

摘　　要：用Gleeble-1500型热模拟机研究TC4-DT钛合金在850~1 100℃、应变速率0.001~10 s-1、变形量70%条件下的高温压缩热变形行为,分析了该合金的流变应力行为以及显微组织演变规律,建立了该合金的本构关系模型以及热加工图。研究结果表明,TC4-DT钛合金在两相区和β相区的热变形激活能分别为544.03 k J·mol-1和264.32 k J·mol-1,分别大于纯α相和纯β相的自扩散激活能,表明TC4-DT钛合金热变形由高温扩散以外的过程控制。在两相区热变形时,原始组织发生了不同程度的球化,且变形温度越低球化效果越好。在β相区热变形时,低应变速率下（0.001~0.1 s-1）主要发生动态再结晶,而高应变速率（1~10 s-1）下主要发生动态回复,动态再结晶行为受到抑制。TC4-DT钛合金的失稳区主要分布在低温高应变速率区域,变形温度主要在850~940℃,应变速率主要在0.1~10 s-1,功率耗散率η值小于28%。Hot compressive deformation Gleeble-1500 at the deformation degree of TC4-DT titanium alloy was carried out with the hot-simulation machine of of 0. 7, over the range of deformation temperature from 850 ℃ to 1 100 ℃, strain rate from 0. 001 s- 1 to 10 s-1. The deformation behavior and microstructure evolution were analyzed, meanwhile the constitutive model and hot processing map were set up. The results reveal that the deformation activation energy of TC4-DT titanium alloy are 544. 03 kJ · mo1-1 in two-phase region and 264. 32 kJ ~ mo1-1 in fl phase region respectively, larger than self diffusion activation energy of pure α and/3 phase, which shows the thermal deformation of TC4-DT titanium alloy is controlled by high temperature diffusion process. When the alloy is deformed in two-phase region, the globularization intensity increases obviously with temperature decreasing. In the β phase region, the dynamic recrystallization occurs at low strain rate （0. 001 s-1 to 0. 1 s-1） and the dynamic recovery occurs at high strain rate （1 s-1 to 10 s-1）. Furthermore, the instability zone of TC4-DT titanium alloy is mainly distributed in the low temperature and high strain rate region where the deformation temperature range from 850 ℃ to 940 ℃, the strain rate range from 0. 1 s-lto 10 s-1, and the power dissipation rate （r/） is lesser than 28%.

关 键 词：TC4-DT钛合金 热变形 本构关系 加工图 

分 类 号：TG146.23[一般工业技术—材料科学与工程]