A NEW MODEL FOR CAVITY NUCLEATION

ＡＮＥＷＭＯＤＥＬＦＯＲＣＡＶＩＴＹＮＵＣＬＥＡＴＩＯＮ①ＬｉｕＺｈｉｙｉＭｅｃｈａｎｉｃａｌＤｅｐａｒｔｍｅｎｔ，ＰｅｔｒｏｌｅｕｍＵｎｉｖｅｒｓｉｔｙ，Ｄｏｎｇｙｉｎｇ２５７０６２ＡＢＳＴＲＡＣＴＢｙｃｏｒｅｃｔｅｖａｌｕａｔｉｏｎｏｆｔｈｅａｃ...

By correct evaluation of the action of interior stress in superplastic deformation, it was believed that interior stress was the driving force for voids aggregation when deformed at high temperature. Based on this principle, a new critical radius model for cavity nucleation was deduced, which points out that critical radius for cavity nucleation is function of exerted stress and grain diameter. The model can be successfully applied to explain the phenomenon that cavity diameter and fraction decreased with grains refining at initial stage in superplastic deformation of Al Li alloys whose grains refined by dynamic recrystallization.