摘要:
利用扫描电镜电子通道衬度（SEM-ECC）技术观察研究了[4 18 41]单滑移取向铜单晶体在不同塑性应变幅下的疲劳饱和位错结构及其在不同温度等时退火条件下的热稳定性.结果表明,在退火温度为300℃时,疲劳位错结构（如脉络结构、驻留滑移带PSB楼梯结构、PSB胞结构和迷宫结构等）均发生了明显回复.当退火温度高于500℃,上述这些疲劳位错结构基本消失,均发生了明显的再结晶现象,并大都伴随有退火孪晶的形成.分析认为,再结晶的发生和退火孪晶的出现不仅与退火温度和外加塑性应变幅有关,还与累积循环塑性应变量有着密切的关系.
Abstract:
The fatigue dislocation structures in cyclically saturated[4 18 41]single-slip-oriented Cu single crystal at different values of plastic strain amplitudeγpl,as well as their thermal stabilities under annealing at different temperatures for 30 min are studied using the electron channeling contrast（ECC） technique in scanning electron microscopy（SEM）.It is found that the dislocation structures, such as veins,PSB ladders,PSB cells,Labyrinths,etc.undergo an obvious process of recovery after annealing at 300℃.However, when the annealing temperature is higher than 500℃,those dislocation structures basically disappear,and the recrystalhzation takes place in all specimens,meanwhile,annealing twins form in most cases.The occurrence of the recrystallization and the formation of annealing twins are related not only to the annealing temperature and appliedγpl,but also closely to the accumulated cyclic plastic strain.
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