Effect of heat treatment on the mechanical properties of TiAl alloy

Heat treatment can influence the microstructure and mechanical properties, in order to homogenize the composition and microstructure, improve the mechanical properties, Ti44Al6Nb0.9La alloy was heat treated at different temperatures and cooling conditions.The experimental results showed that macro-grains grew larger with the elevated temperature.The near-lamellar microstructure was obtained after heat treatment of 1200°C for 2 hours, which transformed into fully-lamellar microstructure as the temperature rose.In addition, linear and lumpish lanthanum compounds were located at inter-lamellae and the colony boundaries, which accumulated more with the accelerated temperature.Micro-hardness test indicated the value of micro-hardness increased differently and the value was the relative maximum when the temperature was 1270°C, as a result of solution strengthening of Nb and precipitation strengthening of La.