Microstructure of TiAl alloy prepared by intense plastic deformation and subsequent reaction sintering

TiAl alloy was prepared by intense plastic deformation and subsequent reaction sintering. The effect of plastic deformation on the microstructure of sintered TiAl alloy was investigated by energy dispersive X-ray spectroscopy, optical microscopy and transmission electron microscopy. The results show that the intense plastic deformation of reacting Ti and Al phases caused by high energy ball milling refines the as-sintered microstructure. The longer the milling time is, the finer the grain size of γ and lamellar (α₂+γ) phases will be. The finer grain size improves the properties of the TiAl alloy. It was also found that the volume fraction of lamellar (α₂+γ) phases increases first, then decreases with the increase of milling time. Based on the experimental results, theoretical discussion was presented.