研究热模拟单向压缩条件下含ZrC粒子的低碳锰(铌)钢在形变诱导相变过程中的铁素体转变动力学关系。研究结果表明:添加ZrC粒子使试验用钢奥氏体晶界的形核率明显增加,影响形变诱导铁素体的形态、分布及晶粒细化效果;高温变形时由于形变诱导的作用,铁素体转变量随应变的增大不断增加,而铁素体晶粒的细化主要是由于动态再结晶的作用,试验用钢在形变诱导相变的变形温度TAe3~TAr3之间的低温区进行变形(TAe3为形变诱导相变的开始温度,TAr3为形变诱导相变的终止温度),可以加速铁素体形核;同时,一定粒径和体积分数(〈0.6%)的ZrC粒子作为形变和再结晶核心,不仅阻碍位错的运动,而且造成位错密度增大,因而提高α-Fe形核率。在温度为900℃、应变速率为1s-1的条件下,试验用钢获得超细组织对应的ZrC粒子临界体积分数为0.6%。
The transitional dynamic relations of deformation induced ferrite transformation of low carbon manganese (niobium) steel containing ZrC particles under unidirectional compression thermal simulating condition were investigated. The results show that nucleation rate at austenite grain boundaries of the tested steel increases when ZrC particles are added, which affects deformation-induced ferrite morphology, distribution and its refinement. The increase of amount of the deformation induced ferrite is due to deformation enhancement in phase transformation. The decrease of size of deformation induced ferrite is due to the enhancement of recrystallization. And the deformation of the tested steel at low temperature in TAe3TAr3 can accelerate ferrite nucleating. Meanwhile, as the deformation and recrystallization nucleus, ZrC particles with definite radius and suitable volume fraction (0.6%), can hinder the movement of dislocation and can increase dislocation density, thus improve α-Fe nucleating rate, the critical volume fraction of ZrC particles is 0.6% which leads to the further refinement of ferrite grains of the tested steel at 900 ℃ and strain rate of 1 s1.