摘要
用电子衍衬技术研究了低碳回火马氏体在拉压对称疲劳过程中碳化物的变化及基体位错结构的回复,根据能量最小原理分析了碳化物与位错的交互作用。结果表明:交变载荷促进了碳原子的扩散及碳化物聚集,从而引起板条界消失,位错重新分布和互毁,因此疲劳软化可以看成交变载荷下的再回火效应。本文并阐述了软化的不均匀性及应变集中效应所引起的疲劳损伤。
The change in carbides and the recovery of dislocation structure in the matrix of tempered martensite during the process of fatigue have been studied with the help of a TEM.According to the principle of minimum energy,the interaction between carbides and dislocation was analyzed.Experimental results showed that the fatigue softening is a continuation of tempering helped by cyclic stress.The stress promotes the dtffusion of carbon atoms and the aggregation of carbides,and consequently,the rearrangement and annihil- ation of dislocation occur.The fatigue damage caused by softening inhomogen- eity and strain localized effect have been revealed.
基金
国家自然科学基金。
关键词
马氏体
回火
碳化物
疲劳软化
Low—carbon martensite
fatigue softening
fatigue damage
