高频振动下TC4钛合金超长寿命疲劳断面特征  

Super Long Life Fatigue Fracture Surface Characteristic of TC4 Under High Frequency Vibration

作　　者：曹小建[1,2] 丁华建[2] 陈圣球 程士超 王清远[1] 

机构地区：[1]四川大学建筑与环境学院,四川成都610065 [2]南通大学建筑工程学院,江苏南通226019

出　　处：《热加工工艺》2015年第20期59-62,65,共5页Hot Working Technology

基　　金：国家自然科学青年基金(11202108);中国博士后基金(2014M552355);江苏省高校自然科学研究面上项目(13KJB130002)

摘　　要：在高频(20k Hz)振动下对对称拉压的TC4钛合金进行疲劳试验,对该合金分别经模拟体液浸泡、喷丸强化和固溶时效加喷丸处理后的超长寿命疲劳断面进行观察。结果表明,高频振动下TC4钛合金超长寿命疲劳裂纹萌生于Al元素富集区或内部氧化物等夹杂处,裂纹源区的小裂纹扩展主要表现为α相晶面滑移;TC4钛合金内部萌生裂纹与高强钢等的"鱼眼"型裂纹不同,即使夹杂处萌生裂纹也不存在明显的夹杂物区和光学暗区。The fatigue tests were performed with a high frequency of 20 k Hz vibration and symmetric tension-compression on TC4 specimens. TC4 specimens were treated with simulated body fluid, shot peening and shot peening after solution-aging treatment, separately. The fracture surfaces of the specimens with super long life were investigated by scanning electron microscopy.The results show that the enrichment region of Al and oxide inclusion are always the core of cracks, and the small crack propagation in crack initiation area acts as the slip of α-phase. The inner crack of TC4 is different from typical ＂fish-eye＂ crack of high strength steel. There is no obvious inclusion area and optical dark area even at the crack core of inclusions.

关 键 词：超声疲劳 钛合金 超长寿命 断面 

分 类 号：TG146.2[一般工业技术—材料科学与工程]