钛合金气瓶疲劳试验壳体开裂失效分析  

Cracking failure analysis of a titanium alloy pressure vessel in hydraulic fatigue test

作　　者：张海 欧阳瑞洁 张永红[1] 姜玉恒 ZHANG Hai;OUYANG Ruijie;ZHANG Yonghong;JIANG Yuheng(Lanzhou Institute of Physics,Lanzhou 730000,China)

机构地区：[1]兰州空间技术物理研究所,兰州730000

出　　处：《压力容器》2021年第7期77-80,86,共5页Pressure Vessel Technology

摘　　要：某TC4钛合金气瓶在疲劳试验过程中发生壳体开裂失效,对断口进行了宏观及微观形貌观察、能谱分析和显微硬度测试。结果表明,气瓶的开裂模式为脆性开裂,开裂原因是由于气瓶外表面局部区域存在Al偏析(含量偏低),偏析区域组织粗大、硬度高、脆性大。在多次充放压(疲劳试验)过程中,裂纹首先从外表面偏析区域起源、扩展,最终发生开裂失效。A titanium alloy gas cylinder failed in the fatigue test due to cracking,and the fracture was observed by the methods such as macrostructure and microstructure analysis,EDS and micro-hardness test.The results show that the failure mode of the gas cylinder is brittle cracking,and the major cause of cracking is Al composition segregation in local areas of external surface of the gas cylinder′s base metal.In the segregation areas,the microstructure is coarse,the hardness is high and the brittleness is big.In the pressurizing and pressure release(fatigue test)process,the cracks initiate and grow in the segregation area of the external surface,which result in cracking failure finally.

关 键 词：气瓶 钛合金 失效分析 偏析 

分 类 号：TH49[机械工程—机械制造及自动化] TG146.2[一般工业技术—材料科学与工程]