装甲钢马氏体相变塑性的实验研究

Experimental study of martensitic transformation plasticity for armour steel

采用Gleeble热模拟实验机对装甲钢马氏体相变塑性进行了研究。通过对热变形中的热应变、组织应变和弹性应变进行分离,从总应变中分离了相变塑性,并得到了相变塑性的定量关系式,采用Greenwood-Johnson模型得到该种材料的相变塑性系数。分析结果表明,该种材料的相变塑性、组织应变和热应变是引起变形的主要原因,相变塑性与组织应变数值相当,在热处理变形分析中不容忽视;随着温度降低及马氏体体积分数增大,相变塑性迅速增大,马氏体体积分数达到0.8后,相变塑性基本保持不变;随着施加应力的增加,相变塑性逐渐增大,相变塑性与施加应力呈线性关系。文章研究结果不仅为该种材料热处理、焊接过程形状畸变和残余应力研究提供基础,还为该材料复杂热力学行为研究提供参考。

The quenching experiments for cylinder specimens of the armour steel under uniaxial loading were performed, where the martensite transformation and transformation plasticity occurred. During the thermo-mechanical processing, the specimen＇s radial strain includes elastic strain, thermal strain, transformation strain and transformation plascticity, and the transformation plasticity was separated from the total radial strain. Based on the Greenwood-Johnson model, the parameter of transformation plasticity was evaluated. The results show that transformation plasticity has equivalence effects on the deformation of quenching specimen.Transformation plasticity increases with the decreasing temperature and the increasing of rnartensitic volume fraction and uniaxial loading. The research contributes to understanding complex thermal-mechaical behavior of armour steel and prediction of the deformation of thermal treatment.