| In order to maintain elevated temperature strength of mechanically alloyed Al-Ti alloys, the rapid coarsening of Al₃Ti must be prevented. It has been known that the addition of the 3rd elements reduces the lattice misfit between Al and Al₃Ti and produces a smaller Al₃Ti precipitate. Room and high temperature tensile strength of MA Al-Ti-X(X=B, V, Ce, Zr) have been reported to be superior to MA Al-Ti because of the dispersion of fine Al₃(Ti+X) precipitates. The creep-rupture properties of Al-Ti-X alloys were studied at 300℃ and 400℃. The rupture strengths were higher than those of Al-8wt.%Ti alloy, and this improvement of creep-rupture strength was due to the dispersion of fine Al₃(Ti+X) precipitates and the strain induced by altering the dimension of the intermetallic`s unit cell at Al-Al₃(Ti+X) interface. Extraordinarily high creep activation energy could be corrected to the values near for self diffusion of Al by the concept of threshold stress of creep. Then the creep mechanism of MA Al-Ti-X alloys could be described as interface controlled. |
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