拉-压及拉-扭载荷下6063合金的疲劳行为  

Fatigue Behavior of 6063 Alloy under Tension and Combined Tension and Torsion Loadings

作　　者：莫德锋[1] 何国求[1] 丁向群[1] 胡正飞[1] 张卫华[2] 

机构地区：[1]同济大学材料科学与工程学院,上海200092 [2]西南交通大学牵引动力国家重点实验室,四川成都610031

出　　处：《材料科学与工程学报》2009年第1期36-39,共4页Journal of Materials Science and Engineering

基　　金：国家973资助项目(2007CB714705);国家自然科学基金资助项目(50771073)

摘　　要：对6063锻造铝合金进行了不同应力幅值下拉-压及拉-扭复合疲劳试验,并用透射电子显微镜观察了疲劳失效试样的位错结构。结果表明:在循环加载过程中,循环硬化占据主要地位,循环硬化的速率和程度对应力幅值和加载路径有依赖性;相同应力幅值下,试样在拉-扭复合加载下失效比拉-压失效形成更为复杂的位错结构,且位错密度更高;位错之间及位错与析出相的交互作用是材料发生循环硬化的主要原因,循环硬化程度越高,疲劳寿命越短。Mechanical fatigue tests were conducted on 6063 aluminum alloy under both tension and combined tension and torsion loadings with different stress amplitudes. TEM was used to examine the dislocation substructures. Cyclic hardening takes the primary in cyclic loading conditions, but the rate and extent of cyclic hardening are quite dependent on particular loading paths and stress amplitudes. Dislocation substructures exhibit different in specimens failed along two loading paths, more complicated dislocation substructures are found under combined tension and torsion loading than that under tension loading with the same stress amplitude. The interactions between adjacent dislocations and between dislocations and particles are the main reason for cyclic hardening, and the fatigue life decreases as the extent of cyclic hardening increases.

关 键 词：锻造铝合金 循环加载 位错结构 疲劳 

分 类 号：TG111.8[金属学及工艺—物理冶金]