Enhancing coatings mechanical performance by advanced laser deposition of WCCoCr-colmonoy composites

Abstract

The manufacturing industry's focus on achieving surfaces with advanced mechanical performance is driven by objectives of competitiveness, sustainability, and efficiency. This study explores the use of Directed Energy Deposition-Laser Beam (DED-LB) process to create Metal Matrix Composites (MMCs) coatings with high mechanical properties, consisting of a nickel-based alloy (Colmonoy 227-F) reinforced with WC-Co-Cr particles, deposited on a 316 L steel substrate. The specific aims of this research are to optimize the DED-LB process parameters and investigate the effect of different reinforcement percentages on the mechanical properties of MMC coatings. The objectives include evaluating the microstructural integrity, hardness, and material distribution of coatings with varying WC-Co-Cr reinforcement levels. The DED-LB technique offers advantages such as localized heat input, rapid cooling rates for finer microstructures, and controlled bonding between substrate and coating. Particularly, it allows for the creation of MMCs, including ceramic-reinforced ones, known for their enhanced mechanical properties. However, managing the dissolution of ceramic reinforcement within the metal matrix remains a challenge.

In this research, two reinforcement percentages (10 % and 40 % WC-Co-Cr) were investigated to optimize the process parameters and enhance mechanical properties. Microstructural analysis showed that coatings with 10 % reinforcement maintained a spherical morphology, while 40 % exhibited a slight dispersion of individual carbide grains within the matrix. Vickers hardness tests indicated hardness values of 375 ± 15 HV for 10 % and 490 ± 10 HV for 40 %, with the pure matrix hardness measured at 325 ± 10 HV. This demonstrates the reinforcement effect in both composite coatings. Chemical composition analysis confirmed proper distribution of elements.

The study demonstrates that MMC coatings produced through laser deposition with optimized parameters exhibit favorable microstructures, increased hardness, and correct material distribution. The scientific novelty of this work lies in demonstrating that a high level of reinforcement (40 %) can be incorporated without metallurgical defects, enhancing the mechanical properties significantly beyond typical reinforcement levels. These findings are essential for improving mechanical performance and wear resistance in high abrasive load applications. The research contributes valuable insights into optimizing DED-LB processes for advanced MMC coatings, crucial for sustainable and efficient manufacturing practices.