New Icosahedral and Amorphous Phases in Mg-Al-Ag System Prepared by Liquid Quenching

New icosahedral (I) and amorphous (Am) phases in the Mg-Al- Ag system have been produced by liquid quenching. Their formation extends in wide ranges of 30 to 67 %Al and 3 to 30 %Ag for the I-phase and 5 to 30 %Al and 3 to 30 %Ag for the Am-phase. Thus, the change of the ratio of Al to Al+Mg brings about a drastic structural change. The decomposition temperature and electrical resistivity at 273 K are 435 to 540 K and about 130 muOmegacm for the I-phase and 352 to 412 K and about 80 muOmegacm for the Am- phase and the I-phase alloys have higher thermal stability and higher resistivity than the amorphous alloys.