Porous TiAl alloys fabricated by sintering of TiH2 and Al powder mixtures

Porous TiAl alloys with different nominal powder compositions were fabricated through a cost-effective powder metallurgy (PM) approach by sintering TiH2 and Al mixed powders. It is found that the pore properties vary with the TiH2 and Al contents, i.e., the nature of the pores can be improved by using different compositions. Furthermore, by detailed structural characterizations, four crystalline phases, i.e., α2-Ti3Al, γ-TiAl, TiAl3, and Ti2Al5, were observed in the fabricated porous TiAl alloys with different compositions. An optimal composition of TiH2-50wt% Al is preferred since its maximum open porosity is about 70% and its viscous permeability coefficient for nitrogen is 1.11 μm2.