Formation of Fe-Ni composite on pure aluminum substrate by laser surface alloying

Abstract

Aluminum is recently attracted the attention of several researchers due to its unique properties; however, it has low hardness, corrosion and mechanical properties. The technique of Laser surface alloying of aluminum substrate with nickel and iron under various processing conditions has been studied. In this paper, a low power CO2 laser was used to alloy pure aluminum substrates with Fe-Ni mixture of various exposures between 10-60 s. It indicates that the laser surface alloying technique using mixed powder with a ratio of 66.67%Ni–33.34%Fe can considerably enhance the hardness of aluminum surface. Microstructures of alloyed layers were studied by scanning electron microscope, optical microscope and the phases were identified by X-ray diffraction analysis. In addition, the micro-hardness of the surface alloyed layer was measured. The hardness was increased from 27 HV0.1 for untreated surface to as high as 53.9 HV0.1 for treating surface due to the formation Al6Fe, Al5Fe2, AlFe3, Al5FeNi, Al0.9Ni1.1 and Al76.8Fe14.