Laser alloying of aluminium with electrodeposited nickel: optimisation of plating thickness and processing parameters

Commercial-purity aluminium (CP-Al) was laser alloyed with electrodeposited nickel using a high-power CW CO2 laser. For process optimisation, nickel w as electroplated at 12, 24 and 35 mu m thickness, and different laser proce ssing conditions were used. The nickel-alloyed aluminium attained a Vickers hardness of 300-950 HV, which is considerably higher than the base alumini um hardness of 35 HV. The laser-alloyed coating (LAC) contains intermetalli c nickel-aluminide phases and a dendrite microstructure. The 35 mu m thick nickel layer is efficient in laser alloying CP-Al for producing a homogenou s coating layer (at a laser energy density of 4.1 kJ) with a high hardness of 600-950 HV and a large case depth (650 mu m). (C) 2000 Elsevier Science S.A. All rights reserved.