材料期刊网

The microstructure of a Ti-47Al-2W-0.5Si alloy has been investigated using high-resolution electron microscopy and analytical electron microscopy. From the three main phases, i.e. gamma, alpha(2) and B2, many precipitates: are formed. Ti(5)Si(3) particles formed in the equiaxed grains match well with the gamma matrix. A new orientation relationship has been identified between the Ti(5)Si(3) and gamma phase. Due to the stabilizing effect of W, B2 phase is formed in the alloy, and it contains much more W, more Si and shows a higher Ti to Al ratio in comparison with the equiaxed gamma phase. Moreover, the gamma precipitates formed in the B2 phase contain small amounts of W and Si. In the (gamma + alpha(2)) lamellar structure, Ti(5)Si(3) and B2 particles are formed. The Ti(5)Si(3) particles were formed mainly by the dissolution of the preliminary B2 particles. This is atcributed to the enrichment of Si and the Ti to Al ratio in the B2 phase.