LC9铝合金加工硬化阶段声发射峰的研究

AN INVESTIGATION ON THE ACOUSTIC EMISSION PEAK IN THE WORK HARDENING STAGE OF LC9 ALUMINUM ALLOY

对不同热处理状态下的LC9铝合金在拉伸至加工硬化阶段的声发射第二峰进行了研究.退火与淬火状态下不出现声发射第二峰,时效状态下出现声发射第二峰,峰高随时效温度及时效时间而变.对该声发射峰的信号进行了幅度分布分析.淬火、退火、及时效态试样在扫描电镜下拉伸均观察到夹杂物断裂过程.分析认为声发射第二峰主要来自运动位错与析出物的交互作用,夹杂物断裂只提供少量大幅度信号.

The second acoustic emission (AE) peak of LC9 aluminum alloy for different heat-treatment dur- ing stretching to work hardening stage was investigated. The AE I peak appears for aged samples but disappears for annealed and quenched samples. The heights of those peaks vary with temperature and time of ageing. The distribution of the amplitude of AE I peaks was analysed. The in-situ stretching under SEM showed that the inclusions were broken not only for aged samples but also for annealed and quenched samples. Therefor the source of AE I peak must have come mainly from the interaction be- tween moving dislocations and solute atoms,and the fracture and debinding of the inclusions were re- sponsible for the events with high amplitude.