真空环境下过时效态2A12合金的疲劳行为  

Fatigue behavior of over-aged 2A12 alloys in a vacuum environment

作　　者：金晓鸥[1] 窦弢 赵慧杰[3] 何世禹[3] 胡焜[1] 

机构地区：[1]黑龙江大学建筑工程学院,黑龙江哈尔滨1500086 [2]哈尔滨市第703研究所,黑龙江哈尔滨150036 [3]哈尔滨工业大学材料科学与工程学院,黑龙江哈尔滨150001

出　　处：《材料科学与工艺》2006年第2期134-136,140,共4页Materials Science and Technology

基　　金：国家重点基础研究发展规划资助项目(G1999065005)

摘　　要：在真空拉-压疲劳试验机上对过时效态2A12合金的疲劳行为进行了研究,并利用扫描电镜分析了真空对疲劳断口形貌的影响.结果表明:真空环境中疲劳寿命明显提高;在低循环应力下,真空环境中的疲劳断裂循环次数比室温大气环境中高近3倍;室温大气和真空环境下的疲劳断口均为穿晶断口,断口中均出现疲劳条纹、台阶和韧窝,且在低循环应力下,疲劳条纹出现的区域较多,但真空环境下疲劳断口中的台阶高度较低,疲劳条纹与韧窝较细小.The fatigue behavior of over-aged 2A12 alloys is studied by using a tensile-compression fatigue testing machine. The effect of vacuum on the fatigue mode is analyzed by means of a Scanning Electron Microscope （SEM）. The results of the analysis indicate that the vacuum environment has made the S - N curve shift to the upper right side resulting in a marked enhancement of fatigue life. Under low cyclic stresses, the fatigue cycles to failure in a vacuum environment increased approximately three times as compared with those at room temperature. The fractures in both the air and vacuum environment assume a transgranular shape. In the frac- tures fatigue striations, steps and dimples and greater frequency of fatigue striations were observed under low cyclic stresses. However, in vacuum conditions, the height of the steps in the fatigue fractures is relatively small, and the fatigue striations and dimples are comparatively thin and slender. Finally discussed were the causes leading to the impact of vacuum on the fatigue behavior of over-aged 2A12 alloys.

关 键 词：2A12合金 过时效态 疲劳 室温大气 真空 

分 类 号：TG148[一般工业技术—材料科学与工程]