無加圧浸透現象を利用した金属間化合物複合材料の作製と圧縮特性

抄録

The titanium aluminide intermetallic matrix composites are synthesized by the spontaneous infiltration of a raw powder phase containing Ti powder with molten pure Al. This paper deals with (i) the effect of adding Al₂O₃ and Al to Ti powder on the spontaneous infiltration and (ii) the result of the compressive test. In the case of using only Ti powder as a raw powder phase, the crucible is destroyed by the rapid increase in temperature due to the exothermic reaction between Ti powder and pure Al melt. However, it was found that the addition of Al₂O₃ particles to Ti powder allows the spontaneous infiltration without the crucible fracture. Excess additions of Al₂O₃ particles prevent the spontaneous infiltration of the mixed powder with molten pure Al. This is because the excess amount of Al₂O₃ particles acts as an obstacle between Ti and Al, and as a result, molten pure Al cannot contact with Ti powder effectively. The result of the XRD analysis suggests the formation of Al₃Ti by spontaneous infiltration. In the case of adding pure Al powder to the raw powder phase, molten pure Al can infiltrate without the addition of Al₂O₃ particles, and the infiltration occurs more thoroughly and the microstructure becomes more homogeneous. The compressive strength of the Al₂O₃ dispersed Al₃Ti is 592 MPa, which is 100 MPa higher than that of the Al₃Ti made by this infiltration process.