65Mn钢的ECAP变形研究

Study of 65Mn steel by equal channel angular processing

等径弯曲通道变形(简称ECAP)能实现材料的强烈塑性变形,获得超细晶组织,从而改善材料的综合性能.成功实现了C方式650℃珠光体钢65Mn的ECAP变形,累积等效真应变～5.75.ECAP5道次后,片层状珠光体组织演变成超细的渗碳体颗粒均匀分布于铁素体基体的组织,铁素体基体平均晶粒尺寸约0.3μm,渗碳体球平均尺寸约0.19μm.实验中,渗碳体的球化可能以两种机制进行:破碎渗碳体片的非均匀长大和细小球状渗碳体颗粒的形核长大.

Equal Channel Angular Processing (ECAP) can carry out the strongly processing and obtain ultrafine grains and improve the properties of materials. In this paper, ECAP was successfully conducted on the pearlitic steel (0.65 wt.%C) at a temperature of 650℃ up to an equivalent true strain of ～5 using route C. The microstructure of lamellae pearlite has evolved ultrafine cementite particles throughout the ferrite matrix uniformly after 5 passes. The ferrite matrix was homogeneous grains and the average grain size was～0.3μm. The average grain size of ultrafine cementite particles was ～0.19μm. There were two possible mechanisms about spheroidization of cementite:the fracture cementite lamellae grows up non-uniformly and the fine spherical cementite particles grows up as the core.