Cyclic deformation and fatigue in TiAl intermetallic compound under plastic strain control

For Mn-containing Ti–48 at.%Al intermetallic compound with a lamellar structure and an equiaxed near-γ structure obtained by heat treatment, a tension–compression fatigue test under plastic strain control was conducted to clarify the fatigue behavior of TiAl. Cyclic hardening occurs significantly in the equiaxed near-γ structure but not in the lamellar structure. The lamellar structure shows the pointed hysteresis loop, whereas the equiaxed near-γ structure exhibits the relatively rounded loop. The variation of the hysteresis loops during cycling was investigated by using the modified energy parameter βE′, and it has been clarified that the strain localization process depends greatly on the microstructure.