Abstract
Gamma titanium-aluminum (γ-TiAl) intermetallic compounds are increasingly used in manufacturing key hot-end components (e.g., blade tenon) in aero engines due to their high specific strength and lightweight properties. Creep feed profile grinding (CFPG) as a crucial precision process that is applied to produce the final profile of the blade tenon. However, sudden surface burns and microcracks of machined γ-TiAl blade tenon often occur because of its low plasticity and high strength during grinding processes, leading to poor surface integrity. In this work, CFPG experiments based on the profile characteristics of γ-TiAl blade tenon were performed and an associated undeformed chip thickness model considering grain–workpiece contact condition was established to explore the evolution of the surface integrity. Subsequently, the surface integrity was analyzed at different positions of the blade tenon in terms of surface roughness and morphology, metallographic structure, microhardness, and residual stress. Results show that the profile characteristics of blade tenon have a significant influence on machined surface integrity because of the thermomechanical effect at various detecting positions. The residual stress was established based on the undeformed chip thickness model considering the profile structure, with a prediction error of 10%–15%. The thermomechanical effect is more obvious at the bottom area, where the surface roughness, work hardening degree, and subsurface plastic deformation range are the largest, while the values at the bevel area are the smallest. Based on the undeformed chip thickness model, a residual stress finite element simulation was conducted by employing thermomechanical coupled effects. In addition, the error between the simulation and the experiment was between 10%–15%. Strain and strain rate equations were established through the relationship between material displacement and depth. The average strain and strain rate of the ground surface when ap is 1.0 mm are 18.8% and 33.2% larger than when ap is 0.5 mm, respectively. This study deepens the understanding of surface integrity under the influence of CFPG γ-TiAl and provides a practical reference and theoretical basis for realizing high-quality profile grinding of other complex parts.
