摘要
具有全珠光体组织的65Mn钢在650℃以C方式等径弯曲通道变形(ECAP)后,珠光体组织中的渗碳体片层以周期性的弯曲变形、周期性的剪切变形、剪切断裂等形式协调ECAP的强烈塑性变形. 渗碳体表现出很强的塑性变形能力,在其内部导入了大量的晶体缺陷,为渗碳体的球化打下了能量基础.变形五道次后,片层状的珠光体组织演变成了超细的渗碳体颗粒均匀分布于铁索体基体的组织.铁索体基体为均匀的等轴晶,平均晶粒大小为-0.3μm.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(Ostwald熟化)和细小球状渗碳体颗粒的形核长大.
Equal channel angular processing (ECAP) in a fully pearlitic structured steel 65Mn was successfully carried out at 650°C via route C in this study. The severe shear deformation of ECAP was accommodated by periodical bending, periodical shearing and shearing fracture etc in the pearlitic lamellae. The cementite in the pearlite has higher plastic deformation capability, and excessive imperfections may be introduced into the cementite, which supplies additional energy driving for the following spheroidization of cementite in subsequent processing. After five ECAP passes, the fully lamellae pearlite evolved into a microstructure of ultrafine-grained ferrite matrix uniformly dispersed with finer cementite particles. The ferrite matrix is homogeneous with an average grain size of -0.3 μm. Two possible mechanisms for the spheroidization of cementite were proposed: heterogeneous growth of the fractured cementite fragments, and the precipitation of new fine spherical cementite particles through nucleation and growth.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2005年第2期200-206,共7页
Chinese Journal of Materials Research
基金
国家自然科学基金59974018资助项目~~
关键词
金属材料
珠光体组织
等径弯曲通道变形
渗碳体
Bending (deformation)
Carbon
Microstructure
Pearlite
Plastic deformation
Shear deformation
Steel
