ZK61镁合金锻造组织动态力学行为各向异性研究

A study on anisotropy of the dynamic mechanical behavior of forged ZK61 magnesium alloy

利用分离式Hopkinson Bar技术,对ZK61镁合金锻造变形组织不同取向的圆柱试样进行动态压缩试验,结合宏观力学响应及微观分析方法,研究了ZK61镁合金不同取向试样的动态力学性能各向异性及变形机制.结果表明:在高应变率条件下,ZK61镁合金锻造变形组织TD及ND方向动态力学性能各向异性不明显,而RD方向与TD及ND方向相比,具有显著的动态力学行为各向异性特点;随着应变率的增加,不同取向试样中孪晶数量变化不同,且ND方向孪晶数量增加最为迅速,RD方向孪晶增加最为缓慢,而TD方向的孪晶迅速增加后明显减少;3个取向的动态力学行为各向异性主要由不同取向的塑性变形机制不同所致.

Using split Hopkinson Bar technology, for the cylindrical specimens made by the different orientation of forged ZK61 magnesium alloy, dynamic compression test have been conducted and the dynamic mechanical behavioral anisotropy and deformation mechanism have been investigated by combining the mechanical response with micro-analysis method. The results show that the transverse direction(TD) and the normal direction(ND) of the forged ZK61 magnesium alloy has few anisotropic characteristic of the dynamic mechanical behavior, while the rolling direction(RD) have conspicuous anisotropic characteristic of the dynamic mechanical behavior comparing with TD and ND. With the increase of strain rate, the change of the number of twins in different orientation specimens is different. The increase of numbers of the twins in ND specimen is the fastest and the slowest in RD specimen, while twins in TD specimen increases rapidly at first and then decreases significantly. The different plastic deformation mechanisms in the different orientations specimens results in the anisotropy of the dynamic mechanical behavior in the ZK61 magnesium alloy specimens.