硅合金化ZA27合金的阻尼性行为

硅合金化ZA27合金具有良好的耐磨性能,但其阻尼性能(Q-1)研究尚不深入.本文利用多功能内耗仪研究了铸态ZA27合金和向ZA27合金中加入4%Si的合金(下称ZA27-4%Si合金)的阻尼行为和相对动态模量,分析了两种合金的阻尼机理.结果表明两种合金的阻尼性能随频率降低和温度升高而增大,阻尼值不随应变振幅变化.ZA27合金和ZA27-4%Si合金具有较高的阻尼性能,在0.1Hz下,合金的室温阻尼分别为6.87×10-3与5.83×10-3.合金的相对动态模量随应变频率提高而增大.100℃以下,ZA27-4%Si合金的相对动态模量不随温度变化.研究表明合金的阻尼是由合金晶界和相界面滑动、位错振荡以及各相的热膨胀系数和弹性模量间差造成的微塑性变形共同造成的.认为ZA27-4%Si合金具有良好耐磨性能和减振性能和强度,适合作为滑动轴承合金材料.

Damping behavior of ZA27 alloys doped with silicon

The ZA27 alloy doped with silicon possesses excellent wear-resistant properties, but the damping capacity of the alloy (i.e. Q-1) has not been studied in detail. In this paper, the damping behaviors and relative dynamic modulus of the as-cast ZA27 alloy and ZA27 alloys doped with 4wt%Si (hereinafter ZA27-4%Si alloy) were investigated using a multifunctional internal friction apparatus and thus the damping mechanisms of the two alloys were analyzed. It was found that damping capacities of the two alloys increase with the increasing of temperature and decreasing of frequency, while it is independent of vibration amplitude. The damping capacities of the ZA27 alloy and ZA27-4%Si alloy are relatively high; the values of Q-1 in ambient temperature are 6.87×10-3 and 5.83×10-3 respectively at a strain frequency of 1.0Hz. The relative dynamic modulus of the two alloys increases when the vibrating frequency increases, and the modulus decreases as temperatures increases in ZA27 alloy. For ZA27-4%Si alloy, the modulus is independent of temperature lower than 100℃; Above 100℃, it decreases slightly with the increasing of temperature. It can be concluded that the slipping of phase interfaces or the viscous sliding of grain boundary, dislocation's oscillation, the infinitesimal plastic deformation that was caused by the difference of elastic module and heat expansion coefficient between phases of the alloy yielded the damping of the alloys. Based on the experiment results, it is proposed that ZA27-4%Si is an excellent alloy with the properties of high damping, high strength, good wear-resistance, and proper for the sliding bearing alloys.