Laser surface alloying of Ni-plated steel with CO2 laser

Laser surface alloying of low carbon steel electroplated with thin (10 mm) Ni using an 850 WCWCO2 laser is reported for the first time. Fe–Ni binary alloys of different concentrations are formed by varying laser traverse speed from 0.5 to 5 m/min. The phase transformation from a to a + g is discussed as a function of Ni contents. Development of microstructure in the modified zone is analysed in terms of solidification rate and Ni concentration. A three-fold increase in the microhardness of the binary alloy is observed. Formation of homogenous, adherent and crack free surface alloys is reported.