Amorphization of Ni_(61)Nb_(39) Alloy by Laser Surface Treatment

摘要

The surface of Ni_(61)Nb_(39) crystalline ingot was treated by laser surface melting with different processing parameters.A fully amorphous layer with a thickness of approximately 10μm could be produced on the top surface under optimal parameters.An amorphous-crystalline composite layer with the depth from 10 to 50μm,consisting of amorphous matrix and intermetallic phases of Ni_3 Nb and Ni_6Nb_7,could be formed.The micro-hardness(about 831HV)of the treated surface was remarkably improved by nearly 100% compared with the value of the crystalline substrate caused by the formation of the fully amorphous structure.A finite volume simulation was adopted to evaluate the temperature distribution in the laser-affected zone of Ni_(61)Nb_(39) alloys and to reveal the mechanism of glass formation in the laser-affected zone.