Effect of Grain Size on Creep-Deformation Behavior of Cu-30massZn Alloy

摘要

The effect of grain size on creep deformationbehavior of a Cu-30massZn alloy has been investigated. Thealloy was tested under two different conditions:using specimensof four grain sizes ranging from 0.012 to 0118mm diameter at623K under a stress of 47.4Mpa(low temperature and highstress),and using specimens of five grain sizes ranging from0.012 to 0.209mm diameter at 723K under 47.4MP(hightemperature and low stress).The creep curves depend markedlyon grain size under all deformation conditions and the creepstrain rate increases with decreasing grain size. The form of thecreep curve depends on stress,temperature and grain size;and inparticular during tertiary creep the fine grained specimens show asudden decrease in strain rate,which we call quaternarycreep.Under all the deformation conditions,the grain sizeexponent is about 1.Consequently it is suggested that themechanism of creep deformation for the tested alloy is related tograin boundary sliding and transgranular dislocation slip.