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在不同塑性应变幅下对[233]共面双滑移取向Cu单晶体进行疲劳实验直至循环饱和,然后在不同温度进行退火处理.利用SEM-ECC和TEM观察疲劳位错结构及其退火后微观结构的变化.结果表明,退火温度为300℃时,位错结构均发生了明显的回复,高应变幅下疲劳样品中甚至出现了部分再结晶.在500和800℃退火,所有晶体都发生了严重的再结晶,并且有大量的退火孪晶出现.随着塑性应变幅和累积塑性应变量的增加,应变集中程度明显增加,为再结晶的发生和孪晶的萌生提供了更大的局部应变能,所以再结晶发生得更为显著,退火孪晶变得更为粗大且数量增加.退火挛晶的形成与层错的出现有密切关系.DSC测试分析表明,再结晶的发生不是突发式的,而是一个缓慢的过程.
Under different plastic strain amplitude, the [233] coplanar double slip-oriented Cu single crystal was subjected to fatigue test until it was saturated and then annealed at different temperatures. The fatigue dislocation structure and its annealed microstructure were observed by SEM-ECC and TEM The results show that the dislocation structure is obviously recovered when the annealing temperature is 300 ℃, and even partial recrystallization occurs in the fatigue specimen with high strain amplitude.All the crystals are severely damaged at 500 and 800 ℃ annealing , And a large number of annealed twins appeared.With the increase of plastic strain amplitude and cumulative plastic strain, the strain concentration increased obviously, which provided greater local strain energy for recrystallization and twinning initiation , So the recrystallization occurred more significant, annealing twins become more coarser and the number increased.The formation of annealing twins is closely related to the occurrence of stratified faults.DSC test analysis shows that the recrystallization is not a sudden , But a slow process.