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在不同塑性应变幅下对[2ˉ23]共轭双滑移和[017]临界双滑移取向Cu单晶体进行疲劳实验直至循环饱和,然后在不同温度下进行退火处理,考察了其位错结构的热稳定性.结果表明,300℃退火处理后,位错结构发生了明显的回复;500和800℃退火处理后,均发生了明显的再结晶现象,并伴随退火孪晶的形成.不同取向Cu单晶体循环变形后形成不同的位错结构,其热稳定性由高到低依次为:脉络结构、驻留滑移带(PSB)结构、迷宫或胞结构.不同取向疲劳变形Cu单晶体中形成的退火孪晶均沿着疲劳后开动的滑移面方向发展,疲劳后的滑移变形程度越高,退火后形成的孪晶数量则越多.但过高的退火温度(如800℃)会加快再结晶晶界的迁移速率,进而抑制孪晶的形成,致使孪晶数量有所减少.
Under different plastic strain amplitude, [2-23] conjugate double slip and [017] critical dual slip oriented Cu single crystals were fatigue-tested until cyclic saturation, and then annealed at different temperatures. The thermal behavior of dislocation structure The results show that the dislocation structure obviously reverts after annealing at 300 ℃ and recrystallizes obviously after annealing at 500 ℃ and 800 ℃ with the formation of annealing twins. After cyclic deformation, different dislocation structures were formed, and their thermal stability from high to low was as follows: veins structure, PSB structure, maze or cell structure. Annealing twin All of them developed along the slip surface after fatigue, and the higher the degree of slip and deformation after fatigue, the more the twins formed after annealing. However, excessive annealing temperature (such as 800 ℃) will accelerate the recrystallization Grain boundary migration rate, thereby inhibiting the formation of twins, resulting in reduced twins.