轧制变形量对Mg-Zn-Y合金组织和性能的影响

使用光学显微镜、动态机械热分析仪、X射线衍射仪和扫描电镜研究了不同轧制变形量对Mg-4Zn-2Y和Mg-4Zn-4Y合金显微组织、力学性能及阻尼性能的影响。结果表明,经轧制后合金中出现片层状的LPSO相;两种合金阻尼性能中与应变振幅无关的阻尼性能Q^-1₀随着轧制变形量的增加,其变化趋势基本一致,与应变振幅相关的阻尼性能Q^-1_h随着轧制变形量的增加而降低,Mg-4Zn-2Y合金以及Mg-4Zn-4Y合金的阻尼机制为位错型阻尼;随着轧制变形量的增加,合金断口中的韧窝数量增加,解理面减少,主要断裂方式由脆性断裂转变为韧性断裂;相同轧制变形量下,Mg-4Zn-4Y合金的强度优于Mg-4Zn-2Y合金,而阻尼性能要低于Mg-4Zn-2Y合金。

Effect of rolling deformation on microstructure and properties of Mg-Zn-Y alloy

Effect of different rolling deformation on microstructure, mechanical properties and damping properties of Mg-4Zn-2Y alloy and Mg-4Zn-4Y alloy was investigated by means of optical microscope, dynamic mechanical thermal analyzer, X-ray diffraction and scanning electron microscope. The experimental results show that the lamellar LPSO phase appears in the alloy after rolling. With the increase of rolling deformation, the change of damping property Q^-1₀ that is independent of strain amplitude is basically the same, and the damping property Q^-1_h related to the strain amplitude decreases with the increase of rolling deformation. The damping mechanism of the Mg-4Zn-2Y alloy and Mg-4Zn-4Y alloy are the dislocation damping. With the increase of rolling deformation, the number of dimples in the fracture surface of the alloy increases, the dissociation surface decreases, thus the fracture mode changes from brittle fracture to ductile fracture. Under the same rolling deformation, the tensile strength of the Mg-4Zn-4Y alloy is higher than that of the Mg-4Zn-2Y alloy, but the damping capacity is lower than that of Mg-4Zn-2Y alloy.