固溶处理对ZK系镁合金力学及阻尼性能的影响

采用光学显微镜、X射线衍射仪、显微硬度计、拉伸试验以及动态热机械分析仪等研究了固溶处理对ZK系（ZK21,ZK40,ZK60）镁合金组织、力学及阻尼性能的影响。结果表明:经固溶处理后,ZK系合金的晶粒尺寸略有长大,第二相溶解、晶格畸变增加。晶界处脆性相的溶解产生的固溶强化效应导致固溶态合金的抗拉强度和显微硬度明显高于铸态。固溶处理后合金的与应变振幅无关阻尼下降、与应变振幅相关阻尼上升,且临界应变振幅明显增大。同一应变振幅下固溶态合金阻尼性能低于铸态;第二临界应变振幅(ε_cr2)增大使固溶态ZK系合金可以在更大应变振幅范围下使用。ZK系镁合金上述阻尼性能的变化可以用Granato-Lücke理论和塑性阻尼理论来解释。 

Effect of solution treatment on mechanical properties and damping capacity of ZK series magnesium alloys

Effects of solution treatment on microstructure,mechanical properties and damping capacity of ZK series( ZK21,ZK40,ZK60)magnesium alloys were investigated by using optical microscopy,X-ray diffraction,microhardness testing,tensile testing and the dynamic mechanical analyzer( DMA). The results show that the grain size of the ZK alloys increases slightly,the second phases dissolve and the lattice distortion increases after solution treatment. The tensile strength and microhardness of the solution treated alloys are significantly higher than that of as-cast alloys due to dissolution of the brittle phase and solution strengthening. After solution treatment,the amplitudeindependent damping declines,the amplitude-dependent damping increases and the critical strain amplitude enhances significantly. The damping capacity of the solution treated alloys is lower than that of the as-cast alloys under the same strain amplitude. The higher second critical strain amplitude( εcr2) of the solution treated ZK alloys indicates that the alloys can be used in the larger strain amplitude range.Damping capacities of the ZK alloys at different conditions can be explained by the Granato-Lücke theory and the plastic damping theory.