超高强冷轧双相钢DP1000高应变速率下的拉伸性能

Tensile Mechanical Behaviour of Ultra-High Strength Cold Rolled Dual Phase Steel DPIOOO at High Strain Rates

使用CMT4105型电子万能试验机和霍普金森拉杆(SHTB)装置研究了超高强冷轧双相钢DP1000在室温下的准静态和动态拉伸力学性能。结果表明:应变速率范围在0.0001—2250 s^(-1),DP1000双相钢具有明显的应变速率敏感性,表现出较强的应变速率增强效应,强度随着应变速率的增加而增加;Johnson-Cook模型能够在一定程度上描述DP1000双相钢在高应变速率下变形行为,但由于应变速率敏感性在高应变速率下吻合程度较差;对Johnson-Cook模型的应变速率效应多项式进行二次化修正后,模型能很好地描述DP1000双相钢在高应变速率下的变形行为,平均可决系数从0.9434提高到0.9850。

Quasi-static and dynamic tensile mechanical behaviour of ultra-high strength cold rolled dual phase steel DP1000 at room temperature and wide strain rates （0.0001-2250 s-1） with electronic uni- versal testing machine CMT4105 and split Hopkinson tensile bar （SHTB） apparatus were investigated. The results show that DP1000 steel is a sensitive material to strain rate, and the strength increases with the increase of strain rate; Johnson-Cook model can represent, to some extent, deformational behaviour for DP1000 steel at high strain rates, but owing to strain rate sensitivity, the goodness of fit is poor at high strain rate. The polynomial of strain rate effect was modified based on Johnson-Cook model, and the modified dynamic constitutive model can make a satisfied prediction to the plastic flow stress of DP1000 steel at high strain rates, and the average coefficient of determination can be improved from 0.9434 to 0.9850.