冷变形对Fe-19Mn合金的组织和阻尼性能的影响

Fe-Mn合金具有良好力学性能的同时,还具有较高的阻尼性能,因此被认为是一种非常具有应用前景的高阻尼合金,并可用于结构和汽车零部件.为了研究冷变形对Fe-Mn合金阻尼性能的影响,通过室温拉伸的方法,对Fe-19Mn合金进行了变形量为0?15％的冷变形处理.采用动态机械分析仪(DMA)对变形前后的Fe-19Mn合金的阻尼...

Influence of cold deformation on microstructures and damping capacity of Fe-19Mn alloy

Fe-Mn alloy is considered to be a promising high damping alloy because of the high damping capacity and excellent mechanical properties, and suitable for constructional and vehicle metal parts applications. In order to investigate the influence of cold deformation on damping capacity of Fe-Mn alloy, Fe-19Mn alloy is deformed to 0-15% by tensile deformation at room temperature. Damping capacity is measured by dynamic mechanical analyzer(DMA). The microstructure evolution is observed by OM, SEM and TEM, and XRD is used to analyze phase constitution and to measure stacking fault probabilities. The results show that the damping capacity of Fe 19Mn is almost linearly increased with amplitude when total deformation is less than 15%, and increases in a relationship which deviates from linear when total deformation reaches 15%. The damping capacity of Fe 19Mn is frequency independent. From G-L plot, the variation of damping capacity below the critical amplitude is interpreted by G-L model, while it′s associated with micro-plastic deformation when above the critical amplitude. With the increase of total deformation, the damping capacity of Fe-19Mn shows different characteristics in different amplitude range: when the amplitude is lower than 20μm, damping capacity increases with total deformation, which has a similar regulation with deformation stacking fault probability change in ε-martensite; when the amplitude is higher than 20μm, damping capacity first increases and then decreases, and shows the best performance at 5% total deformation, which has a similar trend with the relative length change of γ/ε phase boundary. It can be inferred that, the variation of damping capacity with total deformation is influenced by deformation stacking fault boundaries in ε-martensite for the former, and by γ/ε phase boundary for the latter. Based on TEM observation of stacking faults and the calculation of stacking fault probabilities in γ austenite, it can also be concluded that stacking fault boundaries in γ-austenite have no obvious contribution to the change of damping capacity of Fe-19Mn before and after deformation.