摘要
采用恒应变速率法,探究了在880~920℃,0.0005~0.005 s^(-1)的温度及应变速率条件下细晶TC4合金板材的超塑性行为,并表征分析了其超塑变形过程中的微观组织演变。研究表明,随着超塑变形温度的升高,合金均发生明显的动态再结晶现象,其超塑变形机制也随之改变。在880℃/0.001 s^(-1)下TC4合金表现为晶界滑动、晶粒旋转和滑动的协同超塑变形机制,表现出最佳的超塑性能,延伸率高达1039%,应变敏感系数m值达0.51。但在920℃/0.001 s^(-1)条件下,由于合金的超塑性依赖晶界滑动和晶内位错滑移的共同作用,TC4合金延伸率仅为746%,应变敏感系数m值降至0.39。相关结果阐释了不同温度及应变速率下TC4合金超塑性能差异的关键原因,对深入研究TC4钛合金超塑变形过程中复杂的力学行为与变形机制具有重要意义。
The superplastic behavior of fine-grained TC4 alloy sheets was investigated by the constant strain rate method at the temperature of 880–920℃with the strain rate of 0.0005–0.005 s^(-1).Furthermore,the microstructure evolution was characterized during the super plastic deformation.The results reveal that with the increase in superplastic deformation temperature,the alloy undergoes conspicuous dynamic recrystallization,and the superplastic deformation mechanisms of the alloy also changes.At 880℃with a strain rate of 0.001 s^(-1),the TC4 alloy exhibits a cooperative superplastic deformation mechanism involving grain boundary sliding,grain rotation and sliding.Under these conditions,the alloy achieves an elongation up to 1039%,accompanied by a notable strain sensitivity coefficient(m)of 0.51.In contrast,at 920℃with a strain rate of 0.001 s^(-1),the alloy’s superplasticity predominantly relies on grain boundary sliding and intragranular dislocation glide,resulting in a diminished elongation of 746%and a reduced m of 0.39.These findings elucidate the critical factors behind the varying superplastic performance of TC4 alloy under different temperatures and different strain rates,which is significant to further study the complex mechanical behavior and deformation mechanism of TC4 titanium alloy during superplastic deformation.
作者
张磊
郭萍
王欢
强菲
Zhang Lei;Guo Ping;Wang Huan;Qiang Fei(Northwest Institute for Nonferrous Metal Research,Xi’an 710016,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2024年第12期3422-3427,共6页
Rare Metal Materials and Engineering
基金
基础加强计划技术领域基金(2021-JCJQ-JJ-0197)。
关键词
TC4
超塑性
动态再结晶
组织演变
TC4
superplasticity
dynamic recrystallization
microstructure evolution
