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通过电阻方法研究了应变为2.89的共析钢在时效过程中析出动力学过程。研究表明,时效过程分为两个阶段:低于200℃(3600s),电阻率随着时效时间先增加后降低;200～298℃,电阻率随时效时间延长而降低。并揭示了大变形共析钢时效机制:大变形后获得的过饱和铁素体和高浓度界面偏聚碳为碳化物析出提供热力学驱动力,而高能界面处为渗碳体晶粒形核提供有效形核位置,碳原子的长程扩散控制着析出碳化物长大。
The precipitation kinetics of eutectoid steels with a strain of 2.89 were studied by means of electrical resistance method. The results show that the aging process is divided into two stages: below 200 ℃ (3600s), the resistivity first increases and then decreases with the aging time; and the resistivity decreases with the aging time from 200 ℃ to 298 ℃. And reveals the aging mechanism of the large deformation eutectoid steel: the supersaturated ferrite obtained after the major deformation and the segregation carbon at the high concentration interface provide the thermodynamic driving force for carbide precipitation, while the cementite grain nucleation at the high-energy interface provides Effective nucleation sites, long-range diffusion of carbon atoms control the growth of precipitated carbides.