Microstructure and Properties of γ-TiAl/Ti2AlC Composites Produced by Reactive Processing from Elemental Powders (特集 ニュ-コンポジット材料) Microstructure and Properties of γ-TiAl/Ti_2AlC Composites Produced by Reactive Processing from Elemental Powders
The γ-TiAI/Ti<SUB>2</SUB>AlC composites with and without impurities, Ni, Cl and P, were prepared by combustion reaction from the elemental powders and homogenized after arc melting. The resulting composition is about 18 vol% Ti<SUB>2</SUB>AlC in the matrix of TiAl with a lamellar structure of Ti<SUB>3</SUB>Al (α<SUB>2</SUB>). In the homogenized specimens, the α<SUB>2</SUB> phase transforms to the precipitated Ti<SUB>2</SUB>A1C particles in the place of solutionizing lamellar structure. The composite material has a high strength both at ambient and elevated temperatures; about 800 and 400 MPa, respectively, with an ambient temperature ductility of 0.7% at bending test. The fracture toughness test also proves the composite homogenized is better than the as cast and value is 17.8 MPam<SUP>1/2</SUP>. The crack propagation in the homogenized composite is zigzag mode and the precipitated particles are main obstacles for the crack propagation. The composite with impurities shows a marginal improvement in the oxidation resistance over the composites without impurities.
粉体および粉末冶金 45(4), 330-335, 1998-04-15
Japan Society of Powder and Powder Metallurgy