Microstructure and Hardness of Laser Melted Layer on Bulk Cu₆₀Zr₃₀Ti₁₀ Amorphous Alloy

The Cu60Zr30Ti10 bulk amorphous alloy was prepared by water cooled copper mold vacuum suction casting.The surface of the alloy was scanned at the velocity of 20,40,60 mm·s-1 by the Nd:YAG laser beam (201.6 W).The microstructure and microhardness at different depths in the melted zone were investigated by means of X-ray diffraction meter,optical microscope,microhardness meter and electronic probe.The results show that two new layers on the surface of the bulk amorphous alloy were formed at 20 mm·s-1 laser scanning.The hardness(873 HV) and corrosion resistance of the second layer in the middle with the thickness of about 200 μm were evidently improved compared with those of the original substrate.Cu atoms accumulated in 0.2-1 μm dispersing microzones.