用内耗方法研究铜的蠕变断裂过程

在文献1]关于工业纯铝研究的基础上,研究了工业纯铜在不同条件下蠕变过程中晶界内耗峰的变化,蠕变条件分为三类:(a)较高温度、较低应力;(b)中等温度、中等应力;(c)较低温度、较高应力;使试样分别发生晶间型、混合型和穿晶型的断裂。由晶界内耗峰的变化可以推知:在较高温度、较低应力的蠕变过程中,晶界强度变化不大;在中等温度、中等应力的蠕变过程中,晶界强度有一定程度的提高;在较低温度、较高应力的蠕变过程中,晶界强度则有比较显著的提高。这说明,在蠕变过程中,晶界强度是变化着的,在不同的蠕变条件下,晶界强化的程度不同,最终导致了不同类型的蠕变断裂。这对于“等强温度”概念是一个修正和补充。 关键词：

A STUDY OF CREEP RUPTURE IN COPPER BY MEASUREMENTS OF INTERNAL FRICTION

On the basis of our previous work 1] on commercially pure aluminum, the change of internal friction peak of grain bound- (Ke peak) in commercially pure copper has been studied in the course of creep. Creep experiments were conducted under different conditions: (a) high temperature and low stress; (b) medium temperature and medium stress; (c) low temperature and high stress; which lead to intergranular, mixed type and transcrystalline rupture respective'y. From the changes of grain boundary peak under different creep conditions, it can be deduced that the strength of grain boundaries is changed little during creep at high temperature and low stress; somewhat increased at medium temperature and medium stress; and considerably increased at low temperature and high stress. The present work indicates that the strength of grain boundaries is changeable during creep. The extent of strengthening of grain boundaries is different under different creep conditions, which is believed to be an important roie to lead to different type of creep rupture. This provides a modification and complement of the idea of "equicohesive temperature".