Materials Science Forum, Vol.426-4, 1673-1678, 2003
High-temperature deformation behaviour of gas atomized TiAl alloy powder compacts
Pre-alloyed powders of two gamma-TiAl alloys produced by inert gas atomization have been consolidated either by HIP or by extrusion. Tensile tests have been carried out with fine-equiaxed, duplex and nearly-lamellar microstructures by using different heat treatment conditions. A slight aluminium content dependence of tensile properties was related to the extent of the lamellar structure. Tensile testing at 800degreesC results in cavitation damage, with an increased density of cavities with increasing strain. Nevertheless, consistent deformation can already be obtained at 800degreesC with only limited cavitation growth. Further progress was achieved with the use of extruded materials that developed fewer cavities. A composition dependence of cavitation was also evidenced since the W-containing alloy was less prone to, cavity formation.