Microstructure and Mechanical Properties of Mo-Si-Al Alloy and Mo-Si-Al/SiC Composite (ニュ-コンポジット材料<特集>) Microstructure and Mechanical Properties of Mo-Si-Al Alloy and Mo-Si-Al/SiC Composite
Mo-Si-Al alloy and Mo-Si-Al/SiC composite were fabricated by the powder metallurgical process from a novel Mo-Si-Al prealloyed powder, and their microstructure and mechanical properties were evaluated. The Mo-Si-Al and Mo-Si-Al/15 vol%SiC mixed powders were hot-pressed in an argon atmosphere. XRD analyses revealed that Mo-Si-Al/SiC composites were composed of MoSi<SUB>2</SUB> (tetragonal, Cll<SUB>σ</SUB> structure), Mo(Si, Al)<SUB>2</SUB> (hexagonal, C40 structure), a-Al<SUB>2</SUB>O<SUB>3</SUB>, Mo<SUB> ?? 5</SUB>Si<SUB>3</SUB>C<SUB> ?? 1</SUB> and β-SiC. Almost no glassy SiO<SUB>2</SUB> phase was found in Mo-Si-Al and Mo-Si-Al/SiC systems contrary to MoSi<SUB>2</SUB> and MoSi<SUB>2</SUB>/SiC. The formation of α-Al<SUB>2</SUB>O<SUB>3</SUB> was attributed to the predominant oxidation of aluminum at the surface of the Mo-Si-Al prealloyed powder. Mo-Si-Al based systems showed the better high-temperature strength mainly due to the elimination of glassy SiO<SUB>2</SUB> and the crystallographical change from t-MoSi<SUB>2</SUB> to h-Mo(Si, Al)<SUB>2</SUB>. Incorporation of fine SiC particles enabled to control microstructure and then to enhance mechanical properties.
粉体および粉末冶金 43(3), 272-277, 1996-03-15
Japan Society of Powder and Powder Metallurgy