摘要
用低频倒扭摆测量了超塑性 Zn-22Al 合金的内耗。实验观察到在频率0.75HZ 的内耗-温度曲线上出现了118℃、190℃两个稳定的弛豫峰:随着扭转频率增加,峰值移向高温区,两种弛豫的激活能分别为:H1=12.3×104J/mol,H2=17.3×104J/mol。还研究了不同预变形量对内耗的影响。随着变形量的增大,低温峰移向高温,峰高增加;高温峰的峰温不变,峰高也增加。但预变形量超过5%,低温峰又向低温移动,峰高降低;高温峰移向高温,峰高与5%预形变的峰高相等。整个实验的背底内耗随温度升高而增加,也随形变量增加而增加。
Internal friction peaks in an industrial zinc-aluminium(22%)with super- plasticity were investigated with inverted torsion pendulum of about 0.75 cps. Experimental results show:(1)peaks,one at 118℃ and the other at 190℃,have been observed when internal friction was measured in air in the course of heating.The position(temperature)of both peaks moved to the high temperature with the frequency increasing.The activation energies of relaxation of both peaks were respectively:H_1=12.3×10~4 J/mol,H_2=17.3×10~4 J/mol.(2)Effects of the amount of different predeformation on internal friction peaks were investigated again.With the amount increasing,the low temperature peak moved to high temperature and peak height was increased; and simultaneously the high temperature peak didn't move and its height rose, When predeformation amount was more than 5%(e·g 6%)the low temperature peak went back to low temperature and its height lowered;and the high temperature peak moved to high temperature but the peak height was the same as the predeformation amount 5%.(3)The background of internal friction rose with temperature or predeformation amount increasing in all measurements.
关键词
内耗峰
超塑性
锌铝合金
合金
superplasticity
internal friction
zinc-aluminium alloy
