(1. 西安理工大学机械与精密仪器工程学院, 西安 710048;
2. 西北工业大学凝固技术国家重点实验室, 西安 710072)
摘 要: 研究了过饱和ZAC27合金在自然时效过程中的组织演变与其阻尼性能的关系。过饱和ZAC27合金时效1 d后，组织中出现了大量的η 相、α相和少量 的ε相。 随时效时间的延长 ，η相、α相和ε相的量越来越多，时效10 d后，β相已分 解完全并消失。 此后各相进一步粒化、聚集，在50 d后形成了较粗大的、由近似等轴的短棒状的α相、η相和ε 相组成的平衡组织。过饱和ZAC27合金在自然时效过程初期， 阻尼性能迅速而明显地提高，在时效第10d时声频阻尼性能达到最高值，约为7×10-3 ；随后阻尼性能缓慢下降,50 d后基本稳定不变, 稳定后的阻尼性能约为4×10-3。过饱和Z AC27合金的阻尼来 源于界面阻尼和位错阻尼，η相和ε相从过饱和ZAC27合金中的脱溶以及溶质原子 和淬火空位 与位错的交互作用是过饱和ZAC27合金阻尼性能产生变化和提高的主要原因。 ZAC27合金均 匀化热处理及自然时效是一种很好的提高阻尼性能的热处理工艺。
关键字: ZAC27合金； 组织演变； 阻尼性能
（1. School of Mechanical and Instrumental Engineering, Xi′an University of Technology, Xi′an 710048, P.R.China；
2. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi′an 710072, P.R.China）
Abstract:The microstructural evolution of supersa turated ZAC27 alloy and its damp ing capacities were investigated systematically in the period of natural ageing. The investigation shows that the microstructure of ZAC27 alloy evolves as follo ws: after 1 day ageing, α phase, η phase and ε phase appear in the alloy， moreo ver, the amount of α phase, η phase and ε phase increase with th e increasing of ageing time; after 10 d ageing, the β phase decomposes and vanishes completely in the alloy； after 50 d ageing, phases gather and form the coarser equil ibrium microstructure which consists of near equiaxed, shot clubshaped α, η and ε phase. Microstructure changes accompany with the variance of dampi ng ca pacity. It is found that the damping capacities varies quickly and obviously du ring natural ageing. The damping capacity reaches the highest value 7×10-3 at th e 10th day. Sequentially, the damping capacity decreases gradually, and reaches a constant value of 4×10-3 after 50d natural ageing. The dampi ng behavior in supersaturated ZAC27 alloy comes from a superposition of two mechanisms: inte rface damping and dislocation damping. The reasons for the great change of dam ping capacity of supersaturated ZAC27 alloy are as follows: 1) the pr ecipitation of η and ε phases from supersaturated β solid solution and 2) the i nteraction of di slocation with vacancies and solute atoms. The results also indicate that solid solution+water quenching+natural ageing is the best heat treatment technique to improve the damping capacity of the ZAC27 alloy substantially.
Key words: ZAC27 alloy; microstructural evolution; da mping capacity
