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在室温下,利用分离式Hopkinson拉杆系统进行了平行和垂直流线方向切割的铝合金2A70圆棒试样的高应变率(1300~2300/s)拉伸实验;利用分离式Hopkinson压杆系统进行了圆柱试样的高应变率(1100~11000/s)压缩实验,分析了应变率与试样切割方向对试样力学性能的影响,并对比研究了不同应变率下试样断口的形貌。实验结果表明,铝合金2A70的屈服强度在应变率达到11000/s时会得到一定提高;垂直流线切割的试样强度略高于平行流线切割的试样;随应变率升高,拉伸试样的断口更为平滑,颗粒细密,但压缩试样会形成环状的粗晶区。最后基于实验数据拟合了J-C(Johnson-Cook)本构模型参数。
The high strain rate (1300 ~ 2300 / s) tensile tests of aluminum alloy 2A70 round rod specimens cut parallel and perpendicular to the direction of streamline were carried out at room temperature using a split Hopkinson tie bar system. The split Hopkinson pressure bar system The high strain rate (1100 ~ 11000 / s) compression experiments of cylindrical specimens were carried out. The influence of strain rate and specimen cutting direction on the mechanical properties of the specimens was analyzed. The morphology of specimen fracture under different strain rates was also studied. The experimental results show that the yield strength of aluminum alloy 2A70 can be improved when the strain rate reaches 11000 / s; the strength of specimen cut by vertical flow line is slightly higher than that of parallel flow line. With the increase of strain rate, The fracture surface of the specimen is smoother and the particles are fine, but the compressive specimen will form a ring-shaped coarse grain zone. Finally, the J-C (Johnson-Cook) constitutive model parameters were fitted based on experimental data.