摘要
在对某大截面TC4 钛合金锻件进行超声波探伤时,发现存在不规则孔洞和黑斑缺陷,故对其进行了元素分析、微观组织观察、织构测试、微区成分分析以及硬度检测,研究了微观组织形态,分析了缺陷产生的原因.结果表明:孔洞缺陷附近 Al、V、Fe 元素出现有规律的波动,产生原因是铸锭冒口的残留,导致锻件内部出现孔洞;黑斑区晶粒粗大、内部应力较为集中、位错密度大、硬度也较高,是一种明显的冶金缺陷,其产生原因是微区化学成分不均匀,造成富α相元素(Al)的偏析.
Abstract
During ultrasonic testing of a large section TC4 titanium alloy forging,irregular hole and black spots were found.In order to find the causes of these defects,elemental analysis,microstructure observation,texture testing,micro area composition analysis,and hardness testing were carried out.The results show that there are regular fluctuations in Al,V,and Fe elements near the hole defect,which is caused by the residual riser of the ingot.The black spot area has coarse grains,concentrated internal stress,high dislocation density,and high hardness,which is a significant metallurgical defect caused by uneven chemical composition in the micro area,resulting in segregation of rich alpha phase element(Al).
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