马氏体体积分数对双相钢变形行为的影响

Effect of Different Volume Fraction of Martensite on Deformation Behavior of Dual Phase Steels

通过Crussard-Jaoul(C-J)分析和n值的分段分析对不同马氏体含量双相钢的变形行为进行了研究。C-J分析时采用连续数据绘制C-J曲线,避免了取点拟合过程中的不连续性,n值的分段分析基于微分原理,直观给出了不同应变量下的n值。结合对两者的分析,认为只有较低马氏体含量的双相钢才具有双屈服特性,并且双相钢的第二阶段硬化的拐点只有在一定量的马氏体发生变形时才出现。同时在小应变量下双相钢中的应变硬化速率随马氏体含量的增加而升高,而在低马氏体含量下n值会出现最大值。

Deformation behaviors of different volume fraction of martensite are investigated by using Crussard-Jaoul （C-J）analysis and n-value. The C-J curve is drawn by using serial data to avoid the discontinuousness in fitting; nvalue divided analysis gives a visual n-value under different strain on the base of differential theory. Combination of the two fitting methods, only the low volume fraction of martensite dual-phase steel has duplex yield character, and the knee point of work hardening in stage Ⅱ only appears when a certain volume fraction of martensite produces plastic deformation. Furthermore, at low strain the work hardening rate （dS/de） will increase with increasing volume fraction of martensite, while the n-value will reach a maximum at low volume fraction of martensite.