Effect of Grinding Surface Integrity on Fatigue Performance of γ‐TiAl Specimens

Gamma titanium‐aluminum (γ‐TiAl) intermetallic compound, owing to its lightweight, high‐temperature resistance and excellent specific strength, is an ideal material for manufacturing key hot‐end components in aero‐engines. Grinding is an effective machining process for γ‐TiAl finishing to obtain good surface integrity, which has a significant effect on the fatigue properties of specimens. The results show that the fatigue performance of specimens is basically the same under different surface roughness, because stress concentration of specimens is mainly affected by the lamellar structure. Furthermore, the surface micro‐hardening rate is a key factor affecting the fatigue performance of specimens; the cycles to failure increase accordingly as the micro‐hardening rate increases. Influenced by the difference in plastic deformation within the material, the larger plastic deformation layer depth has a significant negative effect on the fatigue performance of specimens. When the grinding depth increases to 40 μm, the TiB 2 ‐phase influence zone reaches 27.6 μm, and the cycles to failure of the specimen sharply decreases to N f = 2.7 × 10 5 . An in‐depth analysis of the fatigue performance evolution law of γ‐TiAl specimens is conducted, which offers valuable reference for optimizing anti‐fatigue machining processes of aero‐engines' key components.