Modification of amorphous materials by various surface modification techniques

Melt spun ribbons (MSRs) of about 20 mm width and 50 μm thickness of Ni86Cr7Si4Fe3, Fe78Si13B9 and Fe75Si13B9Nb3 alloys are prepared melt spinning techniques under high vacuum. 10 mm thick bulk ingots of Zr54Cu29Ni9Al8 and Zr52Cu18Ni15Al10Ti5 alloys are prepared by Cu mold casting technique. The selected samples of appropriate size were modified by various techniques. Laser beam melting (of Zr-based alloys) results in crystallization at the modified surface while bulk sample remains still amorphous. The NiZr2 primary phase and CuZr2 metastable phase was detected in a few areas of irradiated samples of Zr54Cu29Ni9Al8 alloy. Ion irradiation by He+ ions of Fe78Si13B9 and Fe75Si13B9Nb3 alloys result in partial crystallization. No significant effect on crystallization was observed in the Fe- and Ni-based alloys by neutron irradiation. Average Vicker's hardness of the as cast and modified materials was measured. About 20–40 % improvement in hardness was observed at the modified surfaces by ion irradiation, neutron irradiation and laser beam melting.