Effect of shot peening on fatigue performance of a lamellar titanium aluminide alloy

Shot peening is assessed as a potential method for improving the fatigue strength of titanium aluminide alloys based on γ(TiAl). Metallographic characterization was performed with regard to surface roughness, microhardness, residual stress profiles, and structural changes occurring in the subsurface region. The fatigue performance that can be achieved by shot peening mainly depends on the compressive stresses left in the surface region, but is also governed by the fine details of the microstructure. In view of the anticipated high-temperature application of TiAl alloys, particular emphasis is placed on the thermal stability of the surface hardening developed by shot peening.