合金沉淀颗粒劈裂的模拟研究(Ⅱ): 弹性能坍塌

对合金沉淀颗粒劈裂过程的模拟发现晶核长大过程中由结构和温度变化引起的体积变化的同时也发生弹性能坍塌现象. 弹性能坍塌方式可以是瞬间坍塌方式也可以是渐进坍塌方式, 计算结果表明: 沉淀是否发生劈裂与弹性能坍塌时刻有关, 而沉淀发生何种劈裂与弹性能坍塌的速率有关. 对弹性能坍塌速率较快的瞬间坍塌, 沉淀是否发生劈裂只决定于弹性能坍塌的时刻, 在沉淀晶核长大到直径为80l到90l之间大小时引入瞬间弹性能坍塌, 则沉淀发生4块型劈裂. 对弹性能坍塌速率较慢的渐进坍塌, 在引入时刻大于τ= 7.5× 10³ s的情况下, 沉淀发生且只发生两块型劈裂.

Simulation of precipitate splitting in an alloy (I I):Elastic energy collapse

The phenomenon of elastic energy collapse (EEC) accompanying the variation of the structure and temperature during the growth of a nucleus is discovered while we study the precipitate splitting in an alloy. There are two ways to introduce the EEC, one is the instantaneous elastic energy collapse (IEEC) and the other is the gradual elastic energy collapse (GEEC). Simulation shows that whether the precipitate is splitted is related to the time when EEC emerges, and that the kind of splitting of the precipitate depends on the rate of EEC. For IEEC, if it is introduced when the diameter of a nucleus reaches about 80l–90l (l=12.18 nm) the precipitate is splitted to 4 blocks. For GEEC, if it is intoduced when the time is larger than τ = 7.5× 10³ s, the precipitate is splitted to 2 blocks.