High Nb-TiAl （Ti-44Al-8Nb-0.2W-0.2B-0.5Y,at.%） ingot was fabricated by vacuum arc remelting （VAR）.The as-cast ingot was hot-isostatic pressed （HIP） and homogenizing annealing processed.The influence of heat treatment temperature and thermomechanical processing on the microstructure and tensile property of the alloy was investigated by X-ray diffractometry （XRD）,scanning electron microscopy （SEM） and tensile tests.It was found that the high Nb-TiAl alloy after HIP and annealing was mainly composed of coarse α2/γ lamellae,β/B2 phase and γ phase and the solidification path of this alloy was:L→L+β→β→α+β→α→α+β+γ→α2+β+γ.The water quenching results showed that the alloy was in α single phase region at 1,340 °C.After heating at 1,340 °C for 30 min followed by furnace cooling,the alloy showed a full lamellar microstructure and its ultimate tensile strength was about 538 MPa,with an elongation of 0.3% at room temperature.Free-crack forged pancakes with fine-grained fully lamellar structure （FFLS） were obtained with an initial deformation temperature of 1,340 °C and the ultimate tensile strength of forged alloy was about 820 MPa,with an elongation of 0.9% at room temperature,which was much higher than that of alloy after HIP and annealing because of microstructural refinement.
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