THE DEPOSITION OF HIGHLY SUPERSATURATED METASTABLE ALUMINUM-MAGNESIUM ALLOYS BY UNBALANCED MAGNETRON SPUTTERING FROM COMPOSITE TARGETS

Aluminium-magnesium alloy coatings over the full composition range have been obtained by unbalanced magnetron sputtering from composite targets. Highly supersaturated single phase solid solutions have been formed over the ranges 0-20% magnesium in aluminium and 0-30% aluminium in magnesium. In the approximate range 45-50% magnesium a single phase amorphous or micro-crystalline glassy metal is formed, and at intermediate compositions the alloys consist of mixtures of the glassy phase and the appropriate solid solution. All the coatings have dense, non-columnar structures and are much harder than conventional alloys, having hardnesses up to 4400 MPa.