Microstructural refinement of cast Ti48Al2W0.5Si alloy by static heat treatment

Abstract

The microstructure of the massive transformed Ti48Al2W0.5Si alloy was studied during tempering in the temperature range of 1100-1360°C. A fine fully-lamellar microstructure with the grain size of 170-220 μm was developed after tempering in the single alpha field. While a duplex structure comprising equiaxed γ grains and lamellar colonies was obtained at 1300-1340°C, a dual structure of fine γ grains and α2(β) plates was observed at 1250°C. After tempering at 1100°C, fine and dense α2 and β particles were precipitated on the massive γ matrix. Compression tests confirmed that the properties of cast Ti48Al2W0.5Si alloy are considerably improved by quenching/ tempering processes.