304L钢热变形过程的力学行为及再结晶组织演变的研究

Mechanical Behavior and Microstructure Evolution of 304L Steel in Thermal Deformation Process

将304L钢在Gleebl-1500热模拟机上进行压缩试验,热变形温度分别为950℃,1000,1 050,1 100,1 150℃;变形速率为0.005,0.05s-1。通过扫描电子显微镜和透射电子显微镜观察试样微观组织和位错组态。研究表明,304L不锈钢高温应力-应变曲线表现为典型的动态再结晶特征;随着变形温度的升高及应变速率的减小,动态再结晶百分数增大。动态再结晶优先在原始奥氏体晶界上形成。304L不锈钢变形后的位错形态和位错密度与变形温度、应变速率以及应变量有关,是加工硬化和再结晶综合作用的结果。

In this paper, hot compression tests of304L austenitic stainless steel were per-formed on Gleeble-1500 thermo-mechanical simulator to study the influence of deformations suchas deformation temperature （950 ℃, 1 000℃, 1 050℃, 1 100℃ and 1 150℃）, strain rate （0. 005s-1 , 0.05s-1 ） on dynamic recrystallization behaviors and dislocation morphology. SEM and TEMwere employed to characterize the sample. Results show that with higher deformation tempera-ture and lower strain rate, the softening effect of steel 304L is stronger. For 304L stainless steelthe high temperature stress-strain curves show typical dynamic recrystallization. As the deforma-tion temperature and strain rate decrease, the dynamic recrystallization percentage increases. Dy-namic recrystallization occurs preferentially in the original austenite grain boundaries to form a ＂necklace-like＂ structure. In certain deformation conditions, the shape and denstry of dislocationsare related with deformation temperature and strain rate,which are the effect of hardening and re-crystallization.