GH4169高温合金螺柱失效分析

Failure analysis of GH4169 superalloy stud

对固定支架的GH4169 M60断裂螺柱进行宏观和微观分析。目视检查断裂表面,发现裂纹的特征是脆性断裂,并且断裂最终发生在螺柱螺纹和螺母的接合处。渗透测试发现,螺柱内有5个平行于螺纹的连续裂纹,通过扫描电镜发现,断裂部位螺纹之间的裂纹呈现出不规则的尖锐边缘,且断裂表面呈现出典型的准劈裂断裂特征。EDS验证了断裂中碳化物相的存在,并分析了碳化物对脆性断裂的影响。分析表明,螺纹易于引起应力集中,从而提高了螺柱对缺陷的敏感性,导致脆性断裂。与无螺纹试样的断裂表面微观形貌相比较,发现断裂与材质本身无关,破碎的碳化物是GH4169韧-脆混合型断口典型特征。

In this paper,macro and micro analysis are made on the GH4169 M60 fracture stud which is fixed bracket.Visual inspection of fracture surface shows that the feature of crack is brittle fracture,and the fracture finally occurs at the joint of the thread and nut.Penetration test finds that five continuous cracks inside the stud parallel to the thread,and SEM finds that the cracks between the threads at the fracture part show irregular sharp edges,and the fracture surface presents typical quasi-cleavage fracture characteristics.By EDS,the presence of carbide phase in the fracture is verified and the effect of carbide on brittle fracture is analyzed.The results show that the thread tends to cause stress concentration,thus enhancing the sensitivity of the stud to defects and leading to brittle fracture.Comparing the fracture surface micro-morphology of the threadless specimen,it is found that the fracture has nothing to do with the material itself,and the broken carbides are the typical characteristics of Inconel GH4169 ductile-brittle mixed fracture.