Effect of Hot Rolling on the Microstructure and Mechanical Properties of Ti3Al Based Dual Phase Alloys

Abstract

ABSTRACTDevelopment of α2-Ti3A1 based dual phase alloys have shown some promising potentials in property improvement by introducing Ti5Si3sulicide phase into the matrix via Si alloying. However, the presence of coarse network of Ti5Si3phase formed by eutectic reaction in the as-cast state also embrittles the alloy. Both hot rolling and powder metallurgy are considered to be the possible ways to refine the Ti5Si3phase in the matrix. Two Ti-Al-Si-Nb alloys whose Si contents are 2 and 5 at. % respectively were arc melted into ingots and then hot rolled to sheets in this investigation. Optical metallographic examination correlates the microstructures of the as-cast and as-rolled alloys with the different rolling amounts, showing that the coarse silicide network is broken into small particles after hot rolling. Mechanical property testing from room temperature to 8000°C indicates that the strength and plastic elongation of the hot-rolled alloys are much higher than those of the as-cast ones. The data obtained in this investigation are comparable with those obtained in the P/M processed specimens. Fracture surfaces of the alloys are also examined.