相变诱发塑性钢中Nb-V析出计算模型

Model for precipitation kinetics of Nb-V bearing transformation induced plasticity steel

在Gleeble 3500热模拟试验机上采用应力松弛的方法研究了Nb-V-C-N系TRIP钢在奥氏体区中的应变诱导析出行为。应力松弛结果表明:在奥氏体区中的应变诱导析出最快温度范围为915～925℃,其最快析出开始时间约6.5 s。同时根据实际测定的PTT曲线和模型计算的结果,推导出Nb-V-C-N系TRIP(ε=0.20,ε=0.1 s-1)的形变储能大约为2860 J·mol-1。奥氏体中的沉淀相形貌只有球形或近似球形一种,析出物经能谱分析为(Nb,V)(C,N),其粒子平均尺寸为12.91 nm。

The strain induced precipitation of a Nb-V bearing transformation induced plasticity steel in austenite was investigated by the stress relaxation method on a Gleeble 3500 simulator. The stress relaxation results show that the fastest precipitation of strain induced precipitation happens when the temperature is between 915 and 925 ℃,and after only 6. 5 s the precipitation begins. At the same time,the strain induces energy(ε = 0. 20,ε = 0. 1 s-1) is derived to be about 2860 J·mol-1 based on the results of tested and the model. Only one kind of precipitated particle,spherical or near spherical,is observed in austenite after stress relaxation test. The spherical particle is determined as(Nb,V)(C,N) by energy dispersive spectrometer analysis,and the average size is about 12. 91 nm.