摘要
采用等温恒应变速率压缩试验研究了TC11钛合金等轴组织两相区980~800℃,应变速率0.001~0.1s^-1,变形程度50%条件下的变形行为,分析了变形参数对应力-应变曲线、微观组织演变机制和规律的影响,建立了该合金两相区变形的热加工图,并采用EBSD技术测试了热变形组织的晶界特征。结果表明:(1)980℃变形,B相是主要变形相,0.001—0.1s。之间的功率耗散效率值在动态回复和再结晶范围内;α相经历了变形促进下的溶解(高应变速率)和聚集粗化(低应变速率)的过程,即α晶粒尺寸和相含量随着应变速率的加快明显减小。(2)950~900℃变形,0.001~0.01s^-1之间的功率耗散效率值在超塑性变形范围内;变形主要是软基体的B相和界面的变形行为;变形过程中,α晶粒尺寸和相含量基本不变。(3)850~800℃变形,α相是主要变形相,发生了连续动态再结晶过程;β相起晶界协调变形的作用。
Hot deformation behavior of TC11 alloy with equiaxed structure was investigated in the twophase region over the range of 980 -800 %, strain rate of 0. 001 -0.1 s^-1, and maximum deformation of 50% by means of isothermal and constant strain rate tests. The effects of thermal-mechanical parameters on stress-strain curves and microstructure evolution were analyzed. And hot processing maps were established. EBSD technique was used for testing grain boundary characteristic of deformation structures. The results in- dicated that: (1) 15 phase was the main deformation phase, and power dissipation efficiency indicated that dynamic recovery and recrystallization occurred in 0. 001 - 0.1 s^-1. Meanwhile α phase experienced solution (high strain rate )and coarsening (low strain rate) promoted by deformation at 980℃. During the process, ct grain size and its amount decreased with strain rate increasing. ( 2 ) Super-plastic deformation indicated by power dissipation efficiency occurred at 950 -900℃, 0. 001 -0.01 s^-1. And the deformation concentrated on soft β phase, interface and grain boundary layers. (3) The deformation mechanism at 850 -800℃ was continuous dynamic recrystallization of α phase which was the main deforming phase, and β was the deformation coordinate phase.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2009年第2期147-152,共6页
Chinese Journal of Rare Metals
基金
山西省自然基金项目(2008011045)资助