On the residual stresses of turbine blade root of γ-TiAl intermetallic alloys induced by non-steady-state creep feed profile grinding

Abstract

The residual stresses produced during the creep feed profile grinding (CFPG) affect significantly the service performance of turbine blade root. As the length of the turbine blade root is rather short, the process of creep feed grinding can hardly reach the steady state. Thus, it's of great importance to study the residual stresses considering non-steady-state creep feed extreme grinding. This article establishes a new simulation model to predict the residual stresses of CFPG γ-TiAl intermetallic alloys blade root with experimental verification. This model considers the thermo-mechanical-structure coupling effects and the cut-in and cut-out stages of CFPG. The error between simulation and experiments was within 19 %. Analysis showed that the grinding-induced residual stresses of the crest areas were generally tensile (less than 100 MPa), while the residual stresses of the bottom and bevel areas were generally compressive between −420 and −180 MPa. Furthermore, it was found that the residual stresses in the stable stage were greater by about 60 % than that in the cut-in and cut-out stages, while without considering these stages, the residual stresses changed slightly with constant values. Finally, the parameters to grind γ-TiAl intermetallic turbine blade root were optimized, on account of the residual stress simulation method within the experimental evaluation in terms of the subsurface microstructure, surface topography, surface roughness, and microhardness.