Compressive Properties of High Nb-TiAl Porous Materials Fabricated by Element Powder Metallurgy

High Nb containing TiAl alloys have a great potential for high temperature applications in aerospace and automotive fields because of their high strength, low density, high modulus, good resistance to creep and high temperature oxidation. Additionally, the porous high Nb containing TiAl alloys by elemental powder metallurgy (EPM) can be extended to many applications, such as insulation, catalytic carrier, and filtering and so on. The compressive behavior of Ti-48A1-6Nb porous alloys fabricated by EPM was studied. The compression was tested at various temperatures ranging from room temperature to 1200 degrees C, and strain rate was 1 X 10(-3)/s, with the objective to evaluate fracture and pore-evolution mechanism. As temperature increases, the mean stress and remained plastic strain range increase, which leads to the failure of porous alloys. The fracture way for compression is transgranular cleavage below 800 degrees C. But at 1000 degrees C, plastic deformation occurs. And at 1200 degrees C the porous materials have been softened and failure under low stress.