Sintering of a Gamma Ti-Al Alloy
Gamma-TiAl alloys are potential replacements for nickel alloys and conventional titanium alloys in the cooler sections of turbine engines, as well as in orbital platform vehicles. The combination of high specific stiffness and good oxidation resistance at intermediate temperatures can provide significant weight savings. However, they have a limited plasticity at room temperature and the tendency to brittle fracture. Powder metallurgy is a near net shape process that allows the parts production with complex geometry at low costs. An improved plasticity of the Ti-Al alloys is received by adding alloying elements and by microstructure modification. An alloy of two-phase structure Ti–48Al–2Cr–2Nb (at.%) was investigated using the blended elemental technique. Samples were produced by mixing of initial metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by sintering at 1500 °C, in vacuum. It was shown that the samples presented a two-phase structure consisting of lamellar colonies of alternating layers of gamma and α2 phase.
Lucio Salgado and Francisco Ambrozio Filho
V. A. R. Henriques et al., "Sintering of a Gamma Ti-Al Alloy", Materials Science Forum, Vols. 530-531, pp. 10-15, 2006