New nickel and cobalt base alloys containing tungsten and carbon are disclosed. The alloys are subjected to rapid solidification processing (RSP) technique which produces cooling rates between 10.sup.5 .degree. to 10.sup.7 .degree. C./sec. The as-quenched ribbon, powder, etc. consists predominantly of amorphous phase. The amorphous phase is subjected to suitable heat treatments so as to produce a transformation to a microcrystalline alloy which includes carbides; this heat treated alloy exhibits high hardness combined with toughness for many applications wherein superhard materials are required.