MECHANICALLY ALLOYED AMORPHOUS METALLIC POWDERS WITH 2ND PHASE PARTICLES

We report on mechanical alloying for solid state amorphizing transformation, combined with a particle dispersion technique, to prepare metal matrix composite materials consisting of amorphous NiZr and magnetic amorphous cobalt-rich CoZr-(Ni-Nb) with added oxide particles of Y2O3. We further study the effect of a uniform dispersion of finely divided Y2O3. On the size and static magnetic properties of mechanically alloyed amorphous powders. A high energy ball mill was used. It is found that for all the completely amorphized samples tested, an addition of a few per cent Y2O3 leads to a drastic decrease in the mean diameter dmed to micron size. For nearly nonmagnetostrictive amorphous powders of Y2O3-CoZr(Ni,Zr), the coercivity rapidly increases with increasing volume fraction of Y2O3. This increase is explained by both a reduction in dmed and a spatial dispersion of fine Y2O3 particles.