800MPa级冷轧双相钢的动态变形行为及本构模型

采用Hopkinson拉杆试验系统对800 MPa级冷轧双相钢(DP800)进行动态拉伸试验,动态拉伸选择应变速率为500、1000和2250 s-1 . 通过比较试验结果得出:双相钢的塑性延伸强度Rp0. 2和抗拉强度Rm与应变速率的关系呈指数形式增加;DP800在高应变速率塑性变形会产生绝热温升效应,计算可得DP800在应变速率为2250 s-1时拉伸变形产生的绝热温升为89℃. 基于J-C ( Johnson-Cook)模型和Z-A ( Zerilli-Armstrong)模型,对DP800的本构模型进行了研究,并对J-C模型应变速率效应多项式进行二次化修正,修正后的J-C模型相较于J-C模型对DP800在不同应变速率下的平均可决系数从0. 9228提高到0. 9886.

Constitutive model and dynamic deformation behavior of 800 MPa grade cold-rolled dual phase steel

The Hopkinson experiment system was used to do the dynamic tensile experiment of 800 MPa grade cold rolled dual phase steel (DP800). The strain rate was determined as 500, 1000 and 2250 s-1. By comparing the experimental results, both the yield strength ( Rp0. 2 ) and the tensile strength ( Rm ) of the dual phase steel increase with strain rate in the exponential form. The plas-tic deformation at high strain rate leads to adiabatic temperature rise effect. The adiabatic temperature rise is 89℃ at the 2250 s-1 strain rate. Based on the J-C ( Johnson-Cook) model and Z-A ( Zerilli-Armstrong) model, the constitutive model of the dual phase steel was researched. The quadratic polynomial of strain rate effect of the J-C model was modified. The average coefficient of determi-nation increases from 0. 9228 to 0. 9886 by modifying the J-C model.