TiAl rods were fabricated by electron beam melting followed by hot isostatic pressing（HIP）and the microstructure and high temperature fatigue properties were examined focusing on HIP temperature. Unique layered microstructure consisting of a duplexlike region and equiaxed γ grain layers（γ bands）is formed in as built samples. The layered microstructure is completely replaced by fully lamellar microstructure by HIP treatment at 1633 K, while it can be maintained at 1523 K or 1463 K. In addition, the volume fraction of the α2 phase in the γ bands can be controlled by selecting HIP temperature, according to the phase diagram of the alloy. The rods subjected to the HIP treatment at 1523 K or 1463 K exhibit higher fatigue strength at 1023 K than as built rods and HIPtreated cast alloys. It was found that the high fatigue strength of the rods at low cycle fatigue life region is caused by inhibition of the crack initiation due to the high ductility. On the other hand, the strength at high cycle fatigue life region is possible to be improved by the suppression of pores and precipitation of the α2 phase in the γ bands though the HIP treatment under appropriate conditions.
