Cladding of Stellite-6/WC Composites Coatings by Laser Metal Deposition

Abstract

This study aims to investigate the microstructure and hardness of multi-layered Stellite-6/WC metal-matrix composites coatings on metallic substrates cladded by laser metal deposition (LMD) for improvement of wear and corrosion resistances. As coating materials, Stellite-6 and WC-12wt.%Co powders were selected. Powder mixtures having various mixing-ratios of Stellite-6 and WC-12wt.%Co were provided vertically on S45C substrates by controlling powder feeding rates of the two powder feeders, individually. Stellite-6/WC composites which consist of three layers with different compositions were cladded on the S45C substrates by laser melting. Cross-sectional microstructure observation was carried out by using an optical microscope (OM). Vickers microhardness tests were conducted to evaluate hardness of the cladding layers and substrates. The experimental results demonstrate that hard multi-layered Stellite-6/WC metal-matrix composites coatings were successfully cladded on the S45C substrates. Property gradients in the Stellite-6/WC composites could be made due to the position-dependent chemical composition and microstructure made by controlling powder feeding rates of an LMD system.

Effects of Laser-Beam Defocus on Microstructural Features of Compositionally Graded WC/Co-Alloy Composites Additively Manufactured by Multi-Beam Laser Directed Energy Deposition

“…Although the average particle size of the Co-Cr-W alloyed powder was smaller than 20 μm, the powder feeding was well controlled. The other calibration results for PFR are available in our previous literature 16 . The Ar shielding gas flow-rate was set at 0.5 l/min through the experiments.…”

“…Vickers microhardness tests were carried out on the cross-section of the composites with a micro Vickers hardness testing machine (HM-220D, Mitutoyo Corporation, Kawasaki, Japan). Figure 4 shows WC-12 wt.%Co beads with the laser defocus Δf of (a) 0 mm and (b) 0.5 mm, and compositionally graded WC/Co-alloy composites consisting of three layers with the laser defocus Δf of (c) 0 mm 16 and (d) 0.5 mm, additively manufactured on the C45 carbon steel substrate by the multi-beam LDED. In Fig.…”

“…WC-12 wt.%Co beads with the laser defocus Δf of (a) 0 mm and (b) 0.5 mm, and compositionally graded WC/Co-alloy composites consisting of three layers with the laser defocus Δf of (c) 0 mm16 and (d) 0.5 mm, additively manufactured on the C45 carbon steel substrate by the multi-beam LDED.…”

<i>In Situ</i> Evaluation of Crack Generation Using Acoustic Emission Technique during Laser Cladding of WC-Co Cemented Carbide via Multi-Beam Laser Metal Deposition

“…In order to suppress generating cracks, applying functionally graded materials is the most promising way for smoothing the thermal stress distribution across layers [2,3]. In our previous study, attempts to fabricate functionally graded materials by the LMD were performed [4][5][6]. In addition, it is important to control the heat input by laser irradiation in cladding layers to suppress generating cracks.…”

Effects of lateral and vertical ultrasonic vibrations on the microstructure and microhardness of Stellite-6 coating deposited on Inconel 718 superalloy through laser metal deposition

“…Wear-resistant Stellite coatings are applied by various methods such as thermal spraying [9], gas tungsten arc welding (GTAW) [10], plasma transferred arc (PTA) [11], flame spraying [12], and laser metal deposition (LMD) [13]. LMD is a laser cladding approach which can be used to fabricate functional, three-dimensional components.…”