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利用平行平面正碰撞方法产生的冲击波对Mg-Gd-Y与AZ31两种典型变形镁合金加载,并对回收后的材料进行准静态压缩实验,采用金相显微镜和透射电子显微镜进行微观组织分析。冲击波加载后,原始固溶态Mg-Gd-Y合金的屈服强度增加了21 MPa,而时效峰状态合金的屈服强度仅增加4 MPa,时效处理后产生的析出相β’使合金的屈服强度增加幅度明显减少;然而,AZ31镁合金的屈服强度增加了40 MPa。Mg-Gd-Y与AZ31镁合金的冲击波加载后力学响应的差异取决于冲击波过程中两者所具有的不同变形机制,冲击波变形后Mg-Gd-Y合金中的孪晶体积分数非常少,其变形机制以位错滑移为主。相比之下,冲击波加载后的AZ31合金中产生了大量孪晶,孪生是该合金的一种重要变形机制。孪晶界在后续再加载过程中成为位错滑移的障碍,从而导致AZ31镁合金表现出更为显著的冲击波强化效果。
Two kinds of typical deformation Mg-Gd-Y and AZ31 magnesium alloys were loaded by the shock wave generated by the parallel plane normal collision method. The recovered materials were subjected to quasi-static compression experiments. The microstructure was analyzed by metallographic microscope and transmission electron microscope. After shock wave loading, the yield strength of the original solid solution Mg-Gd-Y alloy increases by 21 MPa, while the yield strength of the alloy in the aging peak state increases by only 4 MPa. The precipitation phase β ’produced by the aging treatment increases the yield strength of the alloy However, the yield strength of AZ31 magnesium alloy increased by 40 MPa. The difference of mechanical response between Mg-Gd-Y and AZ31 magnesium alloy after shock wave loading depends on the different deformation mechanism of the two during the shock wave process. The twin crystal volume fraction in Mg-Gd-Y alloy after shock wave deformation is very small, Deformation mechanism to dislocation slip based. In contrast, a large number of twins were produced in the AZ31 alloy after shock wave loading, and twinning was an important deformation mechanism of the alloy. The twin boundaries become dislocations of dislocation slips during the subsequent reloading process, which leads to the AZ31 magnesium alloy showing more significant shock wave strengthening effect.