DOI: 10.5176/2251-1857_M312.11
Authors: S. M. Shahmiri, M. S. Shahriary, M. Cheraghzadeh
Abstract: In this paper, the effect of different heat treatment processes on the rejuvenation of microstructure and mechanical properties of Nimonic 80A first stage gas turbine blade were investigated. As-received microstructure of the blade consisted of a continuous film of M23C6 type carbides at the grain boundaries. This can lead to a reduction in ductility of the blade and create suitable sites to initiate and propagate cracks and therefore premature failure of blade. However, by using a proper heat treatment, including solution treatment and controlled cooling rates and aging, one can resuscitate the microstructure of degraded blade and mechanical properties. To obtain this, blades were solutioned at 1080ºC for 8hr, and then different treatments were carried out on them. According to achievements of this study, using slow cooling after solution treatment and two steps aging can lead to the best microstructural and mechanical properties.
Keywords: Rejuvenation, Heat treatment, Nimonic 80A, Long-Term exposure
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