基于剧烈塑性变形的超细晶中碳钢制备技术  

Manufacture Ultra-fine Grain Medium-carbon Steel by Severe Plastic Deformation

作　　者：汪建敏[1] 陆晋[2] 周孔亢[3] 许晓静[4] 姜银方[4] 

机构地区：[1]江苏大学材料科学与工程学院 [2]江苏大学电气信息工程学院 [3]江苏大学汽车与交通工程学院 [4]江苏大学机械工程学院

出　　处：《农业机械学报》2006年第12期209-212,共4页Transactions of the Chinese Society for Agricultural Machinery

摘　　要：用实验方法研究了中碳钢两相组织在等通道角挤压过程中的强烈塑性变形行为和组织演化过程。实验结果表明,用BC挤压路径经过4道次变形后开始出现纳米级晶粒。中碳钢两相组织的变形行为和组织演化过程为:前两道ECAP,强烈剪切变形集中发生在铁素体内,使铁素体原始晶粒中产生了大量位错缠结和位错胞,随挤压道数的增加,珠光体也开始参与剪切变形,渗碳体由原来的条状被剪切断裂而被细化,成为颗粒状,其粒状平均尺寸至1μm,同时所形成的高密度位错铁素体显微组织逐渐演化变成等轴显微组织。挤压四道次后,位错胞崩塌形成大角度晶粒,其铁素体平均晶粒尺寸至200nm。Severe plastic deforming behavior and microstructure evolution of two phases in mediumcarbon steel during equal channel angular pressing （ECAP） were investigated by experimental method. Experimental results showed that the nano-scale grains could be formed after four passes ECAP with Bc route. The processing of grain refinement of two phases in medium-carbon steel could be described as follows; in the first place the severe plastic shearing deformation took place in the regions of ferrites at first two passes ECAP and produced a large number of dislocation twines and dislocation grains. With the consequent ECAP the severe plastic shearing deformation was also produced in the regions of, pearlites lamellar pearlites were broken down and were converted into granular pearlites with an average size of -1μm, After four passes there was the homogeneous equiaxed ultra-fine grains with boundaries of high angles in ferrites and with an average grain size of～ 200 nm.

关 键 词：等通道角挤压 超细晶 组织演化 剧烈塑性变形 纳米晶中碳钢 

分 类 号：TG146.1[一般工业技术—材料科学与工程] TG376[金属学及工艺—金属材料]