Process and materials design for laser cladded inconel-625/tungsten carbide wear-resistant composite coatings

Abstract

Tailoring materials’ microstructural characteristics to meet mechanical functional requirements is quite critical in designing wear resistant coatings. To the best of our knowledge, no study had related carbide dissolution ratio (CDR) in laser cladded (LC) Inconel 625 coating and its microstructural parameters to its wear performance. Hence, this study explores how laser processing and materials parameters influence CDR, microhardness (MH) and volume of materials loss (VML) of fiber-laser deposited Inconel 625 composite coatings reinforced with tungsten carbide (WC-86) by employing response surface methodology (RSM) via central composite design (CCD). Furthermore, the nature of inter-relationship between the CDR in laser cladded Inconel 625 composite coatings, microstructural parameters (average mean free path and size of retained particles, and MH) as well as VML was explored to determine appropriate process and materials parameters to optimise the wear resistance of the coatings. A fully consolidated composite coating characterised with uniformly distributed retained WC86 particle size of 40 m; mean free path of 30 m within the Inconel 625 matrix; MH = 852 HV0.5; CDR = 77.08% has the most desirable wear resistance (VML = 9.42mm3 ) when processed with appropriate laser energy density (19.70 J/mm2), inconel content (70wt%) and shielding gas flow rates (6.00 l/min). This study provides new insight, for coating manufacturers, on how CDR and microstructural parameters can be manipulated as LC process and materials variables are altered with a view to designing most desirable wear resistant composite coating.