Failure analysis of gas turbine first stage blade made of nickel-based superalloy

Case studies in engineering failure analysis Pub Date : 2017-04-01 DOI:10.1016/j.csefa.2017.04.002

A.M. Kolagar, N. Tabrizi, M. Cheraghzadeh, M.S. Shahriari

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引用次数: 50

Abstract

Various degradation mechanisms are characterized in gas turbine rotor blades due to service conditions such as: high temperature and stress. Failure of turbine blade can have the tremendous effects on the safety and performance of the gas turbine engine. This paper investigates a first stage turbine blade failure in a 6.5 MW gas turbine. The blade is made of nickel-based superalloy, and the failure occurred in the airfoils after 6500 h of operation. Several examinations were carried out in order to identify potential failure reasons such as: visual examination, fractography and microstructural characterization used by optical and scanning electron microscopes (SEM) and energy dispersive X-ray (EDX). The precipitated phases morphology (carbides and γ′ (Ni3Al)) changed in the airfoil for example γ′ resolved and re-deposited in addition to decomposition of carbides. Furthermore, the fracture surface exhibits the local melting occurred and re-solidified in the leading edge. From analysis and experimental results of this study, overheating is shown to be the main reason of blade failure.

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镍基高温合金燃气轮机一级叶片失效分析

燃气轮机转子叶片在高温、应力等工况下存在多种退化机制。涡轮叶片的失效对燃气涡轮发动机的安全和性能有着巨大的影响。本文对某6.5 MW燃气轮机一级涡轮叶片失效进行了研究。叶片为镍基高温合金，运行6500h后出现故障。为了确定潜在的失效原因，进行了几项检查，如目视检查、断口分析和使用光学、扫描电子显微镜(SEM)和能量色散x射线(EDX)进行的显微组织表征。除碳化物分解外，翼型中析出相(碳化物和γ′(Ni3Al))形貌发生变化，γ′析出并重新沉积。断口前缘出现局部熔化和再凝固现象。从分析和实验结果可以看出，过热是叶片失效的主要原因。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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Case studies in engineering failure analysis

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