This chapter discusses the failure of superalloy components in high-temperature applications where they are subject to the effects of microstructural changes, melting, and corrosion. It explains how overheating can deplete alloying elements and alter the composition and distribution of phases, and how these processes contribute to microstructural changes as a function of time, temperature, and applied stress. It also describes several failure examples and discusses related issues, including damage recovery, refurbishment, and repair.

This appendix provides detailed information on design deficiencies, material and manufacturing defects, and service-life anomalies. It covers ingot-related defects, forging and sheet forming imperfections, casting defects, heat treating defects, and weld discontinuities. It shows how application life is affected by the severity of service conditions and discusses the consequences of using inappropriate materials.