PRODUCTION OF BULK AMORPHOUS MG85Y10CU5 ALLOY BY EXTRUSION OF ATOMIZED AMORPHOUS POWDER

Amorphous Mg85Y10Cu5 powders with a particle size fraction less than 25 mum were produced by using a newly designed high-pressure argon atomization-consolidation equipment in which each content of oxygen and moisture was controlled to be less than 1 ppm. The extrusion of the amorphous powders at 373 K causes the formation of a bulk alloy having the nonequilibrium structure which is the same as that for the as-atomized powders. The thermal stability of the extruded alloy is also the same as that for the as-atomized powders. The Young's modulus, compressive fracture strength and fracture elongation at R.T. for the bulk alloy are 46 GPa, 750 MPa and 1.8%, respectively, which are nearly the same as those for the melt-spun amorphous ribbon with the same alloy composition. The fracture surface of the bulk alloy consists mainly of a vein pattern. No appreciable trace of the original boundaries between the powders is seen and hence the powders seem to have a truely bonding state. The good consolidation tendency is presumably because of the clean surface state for the atomized powder by the use of the closed preparation equipment.