ZA27合金低频阻尼行为及其微观组织

Low frequency damping behavior and microstructure of ZA27 alloy

通过对锌铝合金ZA27进行365℃固溶和250℃人工时效,在0.1、0.3、1.0Hz 3个振动频率下,测试了铸态和固溶时效态合金从室温到400℃的阻尼随温度、频率、应变振幅的变化规律,研究了阻尼行为与相应微观组织之间的关系。根据Al-Zn二元合金平衡相图,分析了ZA27合金在平衡和实际冷速下所结晶的铸态和固溶时效组织。结果表明:铸态ZA27合金阻尼的大小与频率有关、与应变振幅无关;在300℃附近阻尼-温度曲线出现的阻尼峰位不随频率的改变而移动,说明在此温度有一级固态相变;经固溶时效后,合金组织明显细化,阻尼特性基本不变,但阻尼峰值明显高于铸态合金,表明固溶时效不改变ZA27合金的阻尼特性,但显著提高了合金的阻尼。

The dependence of damping on temperature, frequency and strain amplitude were examined in cast and aged ZA27 alloys from room temperature to 400℃ under 0.1, 0.3, and 1.0Hz vibration frequencies. According to Al-Zn equilibrium phase diagram and the observation of microstructure, it is found that the magnitude of damping of as-cast ZA27 alloy is related to the frequencies and no significant effect of strain amplitude on damping magnitude is observed. Peaks of damping in ZA27 alloy around 300℃ come from the first order phase transformation. The damping features are not changed, however the damping capability of ZA27 alloy is improved after solid solution at 365 ℃ and then artificial aging at 250℃.