非比例加载路径下TRIP钢的应变硬化行为

通过大试样拉伸与小试样拉伸相结合的方法,分析冷轧TRIP780钢的瞬时应变硬化速率随应变水平的变化规律,详细讨论不同应变路径下TRIP钢应力应变曲线体现出的硬化特性,并对微观组织的演变进行扫描电镜观察。结果表明,TRIP钢不仅具有较高的初始硬化能力,而且具有较长应变范围内的后续硬化能力;非比例加载路径下TRIP钢应力应变曲线表现出了软化效应、瞬时硬化能力和相交效应;加载路径的改变,可引起位错的运动方向和稳定性发生改变,从而影响硬化行为。

Strain hardening behavior of TRIP steels under non-proportional loading path

By large specimen tension followed by small specimen tension,the varying principle of the instant strain hardening rate upon the strain for cold-rolled TRIP780 steel was analyzed.The strain hardenability displayed by the stress-strain curves under different strain paths for TRIP steel was discussed in detail.Besides,the microstructure evolution during the plastic deformation was observed by SEM.The results showed that TRIP steel not only had high initial strain hardenability but also had a stronger further hardenability over a large strain range.When TRIP steel was loaded under non-proportional strain paths,the stress-strain curves displayed the soft effect,instant work hardenability and the cross effect.The change of strain path could make the dislocations alter their moving direction as well as their stability,which in return affected the hardening behavior.