热处理对双辊铸轧ZK60镁合金组织及阻尼性能的影响

Effect of Heat Treatment on Microstructure and Damping Capacity of Twin Roll Cast ZK60 Alloy

采用双辊铸轧法制备了ZK60镁合金条带,采用金相显微镜(OM)和动态机械分析仪(DMA)研究了热处理后ZK60镁合金条带的组织和阻尼性能。退火处理后,组织较为均匀。T6处理后组织转变为均匀的等轴晶。在温度-阻尼谱中出现了2个温度阻尼峰,P1峰为弛豫型阻尼峰,其激活能为132 kJ/mol,P2峰为非弛豫型再结晶阻尼峰。T6处理条件下,时效时间为6 h时,呈现典型的位错型应变-阻尼图谱;在其他时效时间下,呈现2种混合位错型的应变-阻尼图谱。T6态双辊铸轧ZK60镁合金的应变-阻尼性能遵循G-L理论。

ZK60 alloy strip was fabricated by Twin Roll Casting（TRC for short） technology. The effect of heat treatment on microstructure and damping capacities was investigated by optical microscope（OM） and dynamic mechanical analyzer（DMA）. The results show that the homogeneous structure of the alloy strip is obtained after annealing treatment, while it transforms into equiaxed recrystallized grains after T6 treatment. The damping peak P_1 is a relaxation process and the activation energy H for P_1 is 132 k J/mol. However, the damping peak P_2 is not a relaxation process but a recrystallized damping peak. The classical curve of strain amplitude dependence of damping capacity of TRC ZK60 strip is present after T6 treatment（aging for 6 h）, but the curves of strain amplitude dependence of damping capacity of TRC ZK60 strip with two different dislocations system occur after other T6 treatment. Strain amplitude dependence of damping capacity of TRC ZK60 strip after T6 treatment abides by the G-L theory.