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通过等温形变研究了形变参数(形变温度、形变速率、形变量)对高强度汽车钢WHT1300HF的微观组织转变和形貌的影响规律。研究结果表明:增加奥氏体等温形变量,有利于铁素体的缺陷形核,促进了形变奥氏体向铁素体转变;奥氏体的形变强化导致马氏体相变阻力增大,马氏体相变开始温度(Ms)下降,细小晶粒数量和小角度晶界数量增多;增加奥氏体等温形变(40%)速率能同时促进马氏体和铁素体相变,但马氏体体积分数和小角度晶界数量减少,细小晶粒数量略有提高;降低等温形变温度加剧奥氏体的形变强化,导致Ms温度下降,马氏体体积分数、小角度晶界比例减少,细小晶粒数量增多,铁素体含量明显增加。
The effects of deformation parameters (deformation temperature, deformation rate and deformation amount) on microstructure and morphology of WHT1300HF high-strength automobile steel were studied by isothermal deformation. The results show that increasing the isothermal deformation of austenite is favorable to the nucleation of defects in ferrite and accelerating the transformation of deformed austenite to ferrite. The austenite deformation resistance leads to the increase of martensitic transformation resistance, The starting temperature (Ms) of martensitic transformation decreases, and the number of fine grains and the number of small-angle grain boundaries increase. Increasing the rate of austenite isothermal deformation (40%) can promote the martensite and ferrite transformation at the same time. However, The volume fraction of austenite and the number of small-angle grain boundaries decrease, while the number of fine grains increases slightly. Decreasing the isothermal deformation temperature aggravates the deformation strengthening of austenite, resulting in the decrease of Ms temperature, the decrease of martensite volume fraction and the proportion of small-angle grain boundaries, Increasing the number of fine grains, ferrite content increased significantly.