Effects of HIPing pressure on microstructures and properties of TiAl alloy

Abstract

Blended elemental Ti-34% Al powders (mass fraction), containing 1.5% TiC, were hot isostatic pressed to prepare TiAl alloys. The effects of HIPing pressure on the sintered density, microstructure, constitutions phase were studied in details. The results show that the density of TiAl alloy increases repaidly with the increase of the HIPing pressure. At the same time, with the increase of pressure, the Ti₃Al phase in matrix disappears. TiC reacts with other substance, forming Ti₂AlC phase, which precipitates at grain boundaries. With the increase of hot isostatic pressing (HIPing) pressure, the shrinkage of the alloys increases, the fine spherical Ti₂AlC phase can meet together and forms a needle-shape Ti₂AlC, and the amount of needle-shaped Ti₂AlC phase increases. The composite material of TiAl containing C can be made easily by HIPing technology.

Keywords

TiAl alloy / hot isostatic pressing / pressure / microstructure / carbide

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