Microstructure Control and Friction Behavior Prediction of Laser Cladding Ni35A+TiC Composite Coatings

Abstract

The premise of surface strengthening and repair of high valued components is to identify the relationship between coating formulation, structure, and properties. Based on the full factorial design, the effects of process parameters (laser power, scanning speed, gas-powder flow rate, and weight fraction of TiC) on the phase composition, microstructure, and element distribution of Ni35A/TiC cladding layer were investigated, followed by the cause identification of wear behavior. Through ANOVA, the correlation was established with good prediction accuracy (R2 = 0.9719). The most important factors affecting the wear rate of the cladding layer were recognized as laser power and particle ratio with a p-value < 0.001. The cladding layer was mainly comprised of Ni3Fe and TiC0.957. The excessive laser power would enhance the process of convection-diffusion of the melt pool, increase dilution, and improve wear volume. High laser power facilitates renucleation and growth of the hard phase, especially the complete growth of secondary axis dendrite for the top region. Increased TiC significantly changes the microstructure of the hard phase into a non-direction preferable structure, which prevents stress concentration at tips and further improves the mechanical properties. The research results are a valuable support for the manipulation of microstructure and prediction of wear behavior of composite cladding layer.

Microstructure and Wear Resistance of Laser Cladding of Fe-Based Alloy Coatings in Different Areas of Cladding Layer

“…A Spanish scholar, Juan Pereira [ 5 ], studied the dry friction and wear properties of NiCoCrAlY and CoNiCrAlY laser cladding layers and AISI (Martensitic stainless steel) 304 austenitic stainless steel at low and high temperatures. Xu Huang [ 6 ] studied the effects of laser power, scanning speed, gas powder flow rate, and TiC mass fraction on the phase composition, microstructure, and element distribution of Ni35A/TiC cladding layer and identified the cause of the wear behavior. The results provided valuable support for the microstructure control and wear behavior prediction of the composite cladding layer.…”

Additively Manufactured Coatings

“…In one of the chapters, the quality of the coating in terms of the microstructure and the process parameters using full factorial design in the Laser-based technique is studied [4]. By manipulating the process parameters, the microstructure and, therefore, the wear characteristics of the composite substrate can be tailored.…”