锰元素对形变强化相变完成时临界应变量的影响  

Effect of Mn on the critical strain for completion of DEFT in low carbon steel

作　　者：田景[1] 刘锦[1] 杨王[2] 孙祖庆[3] 薛卫京[1] 

机构地区：[1]泰山医学院放射学院医药机械教研室,山东泰安271016 [2]北京科技大学材料科学与工程学院,北京100083 [3]北京科技大学新金属材料国家重点实验室,北京100083

出　　处：《材料热处理学报》2006年第4期40-43,48,共5页Transactions of Materials and Heat Treatment

基　　金：国家科委高技术研究计划(2001AA332020)

摘　　要：利用形变强化相变机制研究了两种锰含量不同的低碳锰钢过冷奥氏体在780℃,以10s-1的速率变形时,锰元素对相变完成时临界应变量εc的影响。结果表明,锰元素对εc的影响很大,主要表现为对组织演变和转变动力学的影响。锰含量增加,主要推迟了相变过程的进行,εc增大。低碳锰钢过冷奥氏体形变强化相变组织演变和转变动力学都分为两个阶段:第一阶段对应着曲线上的斜率接近4,铁素体在原奥氏体晶界形核;第二阶段在曲线上表现n值减小,大约1.0-2.0,对应着铁素体在奥氏体晶内高畸变区大量反复快速形核,直至相变完成。锰含量增加,铁素体晶粒细化显著。Based on the mechanism of deformation enhanced ferrite transformation (DEFT), the effect of Mn on the critical strain (Εc) for the completion of DEFT were investigated when the undercooled austenite in two different low carbon-manganese steels were deformed at 780°C and strain rate of 10 s-1. The results show that Mn has a strong effect on Εc and the effect on microstructural evolution and transformation kinetics is observed. The transformation process is retarded and Εc increases with increasing Mn content. The microstructure evolution and transformation kinetics can be divided into two stages. The value of curve slope is close to 4 at the first stage, corresponding to the nucleation at primary austenite grain boundaries. The value of curve slope is decreased to 1.0-2.0 at the second stage, corresponding to the nucleation at the areas ahead of formed ferrite grains where new nucleation sites are kept creating till the completion of DEFT. In addition, with increasing Mn ferritic grain size decreases.

关 键 词：锰元素 低碳锰钢 形变强化相变 临界应变量 组织演变 

分 类 号：TG142.1[一般工业技术—材料科学与工程]