Abstract
Ni3Al matrix composite alloys with 0, 20, 40, 60 and 80vol%TiC particles were produced by mechanical alloying - hot press process using pure Ni, pure Al and TiC powders. Morphological change of powders during mechanical alloying process was studied. Also, the microstructures and the mechanical properties as well as the oxidation properties of sintered specimens were investigated. Fine powders with diameter of less than 10μm were produced by mechanical alloying. Sintered composite alloys were found that they consist of Ni3Al matrix with small amount of γ phase and uniformly dispersed TiC particles. Although the plastic strain was observed for the 0- 40vol%TiC alloys at any temperature investigated, 60 and 80vol%TiC alloys deformed plastically only at higher temperatures than 673K and 1073K, respectively. The flow stresses for alloys with 0-40vol%TiC exhibited the plateau region from 400K to 700K, and then decreased markedly. It was revealed that the strain rate sensitivity exponent (m value) for the base matrix alloy was over 0.4, indicating the development of superplastic deformation. Mass gain during oxidation test at 1273K increased with TiC volume fraction.
