Effect of Rejuvenation Heat Treatment on the Degraded Turbine Blades

Abstract

This paper presents a novel approach to estimate the extended lifetime of first-stage turbine blades made of directionally solidified GTD-111 nickel-based superalloys. These turbine blades were removed from land-based industrial gas turbines for power generation. In addition, this new way to evaluate the lifetime extension of degraded turbine blades after rejuvenation heat treatment is based on knowledge of newly introduced degradation index (Di) evolution. The rejuvenation heat treatment (RHT) process offers an extension of 36% in blades lifetime. Effect of the RHT on the aged γ-γ’ microstructures is presented and discussed.