Measurements of melting temperatures of quasicrystalline Al-Mn phases

Melting transformations in metastable quasicrystalline Al-Mn phases have been measured for the first time, by use of a new rapid electron-beam heating technique applied to surface layers with 14.8–20.5 at. % Mn. The melting temperature for icosahedral ${\mathrm{Al}}_{80}$ ${\mathrm{Mn}}_{20}$ is directly measured to be 910±20 °C, and is believed to be near the congruent melting point. The decagonal-phase liquidus at the same concentration is inferred to be 965±20 °C. The melting temperatures of the icosahedral phase are ∼30 °C below those of crystalline compounds of the same compositions.