無加圧浸透法により製造したAl₂O₃, Ti粒子分散Mg基複合材料の組織と特性に及ぼすプリフォーム作製条件の影響

抄録

Pressureless infiltration of molten magnesium into the [Al₂O₃+Ti] blended powder preform was attempted at 700°C in order to fabricate magnesium matrix composites. The titanium powder as an infiltration aid was mixed with the Al₂O₃ powder to improve wettability. Effects of Al₂O₃/Ti volume ratio, relative density of the preform and Al₂O₃ particle size on the pressureless infiltration behavior and mechanical properties of the composites were investigated. Molten magnesium did not infiltrate into Al₂O₃ powder preform at all. The spontaneous infiltration took place by adding a certain amount of titanium powder in the Al₂O₃ powder preform. When the relative density of the preform increased, more titanium fraction was necessary for the spontaneous infiltration. Decreasing the Al₂O₃ particle size made the spontaneous infiltration difficult. The hardness and the compressive strength became higher as Al₂O₃/Ti volume ratio or relative density of the preform increased. By using the finer Al₂O₃ particles, the mechanical properties were improved as well.