Effect of long-term service exposure on microstructure and mechanical properties of Alloy 617

摘要

The present work was carried out to investigate the effect of long-term service exposure on microstructure and mechanical properties of a gas turbine hot gas path component, made of Alloy 617. The results showed significant service-induced microstructural changes, such as excessive grain boundary Cr-rich M_(23)C_6 carbides formation and some oxidation features in the exposed material in compare with the solution-annealed material. Also it was found that the yield strength and hardness of the alloy have increased while the ductility of the alloy has decreased. In the similar test conditions, the stress-rupture life of the exposed alloy decreased considerably compared to the solution-annealed sample, which could be attributed to the microstructural degradation, especially formation of continuous M_(23)C_6 carbides on grain boundaries.