Effects of Zr addition on the phase stability of L12-based Al-Ti-Cr alloys

Zr was added to the Al-21Ti-23Cr (L12 + Cr2Al) alloy to improve the L12 phase stability at temperatures around 800 °C. It was found that the addition of Zr effectively reduced and delayed the decomposition of the L12 matrix into L12 and Ti(Cr,Al)2 phases in the Al-21Ti-23Cr alloy. Furthermore, the temperature range of the L12 matrix decomposition was narrowed when Zr was added to the Al-21Ti-23Cr alloy. It is suggested that improvement of L12 phase stability by the addition of Zr could be the result of two factors. First, the movement of the L12 single-phase field could be reduced by the addition of Zr, possible decreasing the fraction of L12 matrix decomposition. Second, atomic diffusion could be suppressed by the addition of Zr, possible delaying the precipitation of the Ti(Cr,Al)2 phase in the L12 matrix.