Refinement of Fully Lamellar Microstructure of Wrought TiAl Alloy and Tensile Properties

For the extruded alloy with the nominal composition of Ti-46Al-3.8(V, Cr, Ni) (at%), the effect of heat treatment on the morphology and volume fraction of beta phase was investigated. Refined fully lamellar microstructure with uniform colony size was obtained by the pinning effect of beta phase on the alpha phase at high temperature. The tensile properties of refined fully lamellar microstructure were tested. The results show that the colony size decreases gradually due to more beta phases within 1320 similar to 1370 degrees C as the temperature increases. The colony size of the alloy after 1340 degrees C/5 min/AC heat treatment is 65 mu m and the B-2 phase distributes dispersedly. This microstructure possesses superior tensile properties at room temperature and high temperature. A few of B-2 phases do not affect the ductility of the alloy at room temperature (RT), and may help to increase tensile stress at high temperature.