超高强度钢30CrMnSiNi2A动态力学性能实验研究

Experimental Study on Dynamic Mechanical Properties of Ultrahigh Strength 30CrMnSiNi2A Steel

运用SHPB实验研究超高强度钢30CrMnSiNi2A在应变率500-5000s^-1时的应力应变关系，并对典型试样进行了金相观察．实验得到30CrMnSiNi2A钢的屈服强度随着应变率的增加从1655MPa增加到1908MPa．基于试样金相和断口分析，30CrMnSiNi2A钢在高应变率冲击加载条件下产生了韧窝型沿晶断裂，导致材料宏观上表现为剪切破坏．结合准静态实验数据，确定了30CrMnSiNi2A钢的Johnson-Cook本构模型的材料参数．

As an outstanding performance aviation material, the understanding of dynamic behavior of ultrahigh strength steel 30CrMnSiNi2A at high strain rates is of importance in a range of applications. The curves of stress and strain in different strain rates （500-5 000 s^-1） of 30CrMnSiNi2A steel are obtained with split Hopkinson pressure bar（SHPB） experiments, and the micro-deformation characters were observed by metallography. The results indicate that 30CrMnSiNi2A steel is sensible of strain rate, and dynamic compression leads to shear failure with the angle 45°. The yield stress increases from 1 655 MPa to 1 908 MPa with increasing strainrate （500 - 5 000 s^-1）. Through metallographic analyses, the failure is found to be dimple intercrystalline fracture under high strain-rate loading. Meanwhile, the material parameters of Johnson-Cook model are determined through the SHPB experiments and quasi-static results.