Preparation of Dense TiAl Intermetallics by Cold Spraying the Precursor–Hot Isostatic Pressing

Abstract

In this study, based on the element powder metallurgy method, a new hybrid method is proposed, which firstly prepares TiAl-based deposit precursors by the cold spraying of mixed Ti and Al powders and then combines this with hot isostatic pressing to achieve the preparation of TiAl-based alloys. This paper explores the effects of deposition parameters on deposition efficiency and coating composition and investigates the evolution of the microstructure and properties of TiAl-based alloys by different hot isostatic pressing parameters. The results show that the prepared TiAl deposits are dense and free of microstructural defects; a high deposition efficiency (75%) and small deviation of coating composition (3 at %) are obtained under the spraying parameters of 5 MPa, 500 °C. The TiAl-based alloy with a dense microstructure can be prepared by controlling the parameters such as temperature, pressure, and heating rate of subsequent hot isostatic pressing.