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研究了单晶和多晶纯铝蠕变过程中的低频内耗。在单晶纯铝中观察到:内耗在蠕变初期单调下降,在蠕变第一阶段后期出现了一个显著的时间内耗峰,在蠕变第二阶段内耗趋于稳定值。多晶纯铝在类似实验条件下则不出现时间内耗峰。 文中分析了出现时间内耗峰的条件和原因,认为它是由于蠕变第一阶段中运动位错的阻尼系数逐渐增大所引起的。文中还从蠕变过程中位错运动的微观机制出发,推导出了蠕变过程中内耗的表达式,满意地解释了实验结果。
The low frequency internal friction in the creep process of single crystal and polycrystalline pure aluminum was studied. It is observed in single-crystal pure aluminum that the internal friction decreases monotonously in the early creep phase, a significant time-consuming peak occurs in the late stage of creep, and the internal friction tends to be stable in the second stage of creep. Polycrystalline pure aluminum in similar experimental conditions do not appear during peak consumption. In this paper, the conditions and causes of peak consumption during the emergence time are analyzed. It is considered that it is caused by the gradual increase of the damping coefficient of the moving dislocations in the first phase of creep. Based on the micro-mechanism of dislocation movement in creeping process, the expression of internal friction in creeping process is deduced, which satisfactorily explains the experimental results.