Nickel aluminide intermetallic coatings (IC) and nickelaluminide intermetallic matrix composite coatings(IMC) with a WC particulate reinforcement weresuccessfully clad onto AISI 420 Martensitic stainlesssteel using a 4 KW Nd:YAG laser with rotary-diskpowder feeding of Ni-Al powder and a Ni/Al + WCpowder mixture, respectively. Under optimizedprocessing with pre- and post-heat treatmentconditions, the clad layers were free of cracks andpores. The microstructure of the IMC was mainlycomposed of re-precipitated and refined WC particlesdispersed uniformly throughout the Ni-Al matrix witha few partially dissolved and undissolved WCparticles. The average hardness of the IC was increasedfrom 330 HV0.2 to 420 HV0.2 by the WC reinforcement.The normalised cavitation erosion resistance (Ren) ofthe IC and IMC were about 3.5 and 284 times that ofthe stainless steel substrate, respectively. The superiorcavitation erosion resistance of the laser clad layerswere explained in terms of microstructure,microhardness and work hardenability
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