Al-4％Cu多晶合金中锯齿形屈服现象的初步时序分析  

PRELIMINARY TIME SERIES ANALYSIS OF SERRATED YIELDING IN Al-4%Cu ALLOY

作　　者：卢俊勇[1] 蒋震宇[1] 张青川[1] 

机构地区：[1]中国科学技术大学中国科学院材料力学行为和设计重点实验室,合肥230027

出　　处：《金属学报》2006年第6期611-618,共8页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目10232030和10372098资助

摘　　要：对Al-4％Cu合金试样拉伸实验的锯齿形应力曲线进行了系统的统计分析,研究了锯齿应力跌幅、跌落时间以及再加载时间等特征物理量随应变、试样厚度和加载应变率的时序演化规律．结果表明,跌落时间对应变不敏感; 1和2 mm厚试样的平均应力跌幅和平均再加载时间均随应变线性增加, 3 mm厚试样的统计结果比较复杂．展示了PLC效应中自组织临界性存在的证据,并通过与经典沙堆模型的对比,结合动态应变时效原理和位错理论,解释了PLC变形带形成的非线性机制．A systematic statistical analysis of the characteristics of the Portevin-Le Chartelier （PLC） effect in Al-4%Cu alloy, including the stress drop amplitude and the reloading time, etc., is carried out. The drop duration is found to be a constant independent of the strain. The average stress drop amplitude and the average reloading time of 1 and 2 mm thick samples increase with strain linearly, while the cases of 3 mm thick samples are much more complicated. The evidence of selforganized criticality is demonstrated, and the nonlinear mechanism in the PLC effect is also explained by comparing with the classic sand-pile model, and by combining with the dynamic strain aging （DSA） principle and the dislocation dynamics.

关 键 词：Al—Cu合金 锯齿形屈服效应 统计分析 自组织临界性 

分 类 号：O344.7[理学—固体力学] O483[理学—力学]