摘要
增材制造大型TC4钛合金横梁成形完成后进行缺陷检查,通过超声检测对梁缺陷的尺寸和位置进行检测,然后通过线切割对相应位置进行取样,磨制抛光后利用体视显微镜、金相显微镜、扫描电镜和能谱检测仪的手段,分别对缺陷类型及形貌进行分析统计,对缺陷附近组织、缺陷内部形貌进行观察分析,对夹杂物成分进行能谱检查,分析得出缺陷类型和形成原因。结果表明:TC4钛合金横梁的孔洞缺陷为熔合不良造成,与成形过程中局部出现搭接率和和Z轴单层行程ΔZ匹配不良的情况有关;夹杂缺陷为氧化物夹杂,是由于熔覆环境受到一定程度的氧气污染,合金熔滴表面反应生成氧化皮夹杂嵌入基体,氧气的存在同时影响熔合不良孔洞附近组织,使其出现α相增多和富氧α层的现象。
After forming,TC4 Titanium alloy additive manufacturing beams were inspected for defects. Defect size and position were tested by ultrasonic inspection and samples were cut down by WEDM. Afterwards,samples were prepared for metallographic analysis. The types and morphology of defects were tested and analyzed by stereoscopy,OM,SEM and EDS analysis. Besides,the micro-morphology near defects was observed and the chemical composition of inclusions was tested by EDS. The results show that the hole defects of titanium alloy beams resulted from poor fusion,which was caused by the mismatch between overlap ratio and Z increment. The inclusion defects are oxide inclusions. The forming environment was polluted by oxygen,so the surface of high temperature molten drop reacted with oxygen,leading to oxide skins,which then were embedded in the beam body.Besides,the micro-structure near poor fusion areas was also influenced by oxygen,where α phase increased and oxygen-rich αlayers formed.
出处
《失效分析与预防》
2018年第1期43-48,共6页
Failure Analysis and Prevention
作者简介
高翔宇（1990年-）男,硕士,主要从事金属失效分析与损伤评价等方面的研究.
