Formation of nanocrystalline particles in glassy matrix in melt-spun Mg-Cu-Y based alloys

This paper reports the crystallization sequence of ternary Mg65Cu25Y10, Mg8 0Cu10Y10 and Mg80Cu15Y5 amorphous alloys. Nanodis-persions of Mg2Cu, hcp-Mg and fcc-Mg ranging from 5 to 20nm have been observed in the melt-spun Mg65 Cu25Y10, Mg80Cu10Y10 and Mg80Cu15Y5 alloys, respectively. The brittleness o f melt-spun Mg-Cu-Y based alloys appears to be due to the nanodispersions o f Mg2Cu intermetallic phase. On the other hand, nanodispersions of terminal solid solution such as hcp-Mg or fee-Mg in the amorphous matrix lead to go od ductility in the melt-spun Mg-rich alloys. The results also indicate tha t the glass forming ability and the thermal stability of amorphous phase ar e not improved by additions of quaternary elements such as Ni, Al, Zn and M m to Mg-Cu-Y based alloys.