交变应力下A356铝合金疲劳行为及微结构演变  

Fatigue Behavior of A356 Aluminum Alloy under Cross-stress-loading and the Fatigue Microstructure Evolution

作　　者：刘晓山[1] 何国求[1] 范宋杰[1] 张卫华[2] 

机构地区：[1]同济大学材料学院金屑基材料研究所上海市金属功能材料开发应用重点实验室,上海200092 [2]西南交通大学牵引动力国家重点实验室,成都610015

出　　处：《材料导报》2007年第10期113-115,共3页Materials Reports

基　　金：教育部"新世纪优秀人才支持计划"(NCET-05-0388);国家自然科学基金项目(50371063);牵引动力国家重点实验室开放课题(TPL0501)

摘　　要：对处于交变应力下A356铝合金的单轴疲劳寿命以及变形行为进行了研究,并与单一应力加载下的加载情况进行了对比。发现先进行高应力加载后换用低应力加载将会显著延长合金的疲劳寿命。合金的循环应变值主要与合金的循环加载应力幅值有关。此外,利用透射电镜的方法观察了在不同循环加载历史条件下合金中微观结构的变化情况,尤其是位错以及位错带的演变规律。并发现了沉淀物附近的位错塞积现象。The uniaxial fatigue life and deformation performance of A356 aluminum alloy under cross-stressloading is studied in this paper, which is compared with the single-stress-loading fatigue. The results indicated that the fatigue life would be extended with first loading at a high stress amplitude and then a low stress amplitude during the fatigue process. The cycled strain of the alloy is mainly related to the stress amplitude of cyclic loading. Still, the mi- crostructure of the alloy during different loading cycles is researched with the help of TEM, especially the evolution of the dislocation and dislocation bands during the fatigue process. Around the precipitates had many dislocations stacked.

关 键 词：交变应力 A356合金 单轴疲劳 位错演变 

分 类 号：TG111.8[金属学及工艺—物理冶金]