Design, advanced manufacturing and characterization of high-energy mechanically alloyed AlCoCrFeNi–TiC cermet particles and high-pressure cold spray coatings: Numerical and experimental investigation

Abstract

In this work, AlCoCrFeNi High-entropy alloy (HEA) powders milled in high energy mechanical alloying with TiC ceramic reinforcements were systematically characterized to evaluate their suitability for cold spray (CS) deposition. Powder morphology, elemental homogeneity, particle size distribution, and phase constitution were investigated using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), laser particle size analysis (PSD), and X-ray diffraction (XRD), respectively. Based on the combined interpretation of SEM, EDS, PSD and XRD results, 95 wt.% AlCoCrFeNi HEA reinforced with 5 wt.% TiC ceramic powder was selected for high-pressure cold spray (HPCS). CS deposition of particles with different morphologies requires a precise understanding of critical velocity to achieve effective solid-state bonding without melting. A numerical approach was developed to predict the critical velocity of spherical AlCoCrFeNi HEA particles and non-spherical milled 95 wt.% AlCoCrFeNi+5 wt.% TiC cermet particles impacting a Ti-6Al-4V substrate under HPCS conditions. A Coupled Eulerian–Lagrangian (CEL) model is developed in Abaqus/Explicit to capture the particle–substrate interaction, including severe plastic deformation and temperature distribution. The predicted critical velocity from the simulation is compared with experimental observations obtained from HPCS deposition of spherical AlCoCrFeNi HEA and non-spherical milled 95 wt.% AlCoCrFeNi+5 wt.% TiC cermet particles, providing qualitative validation of the numerical approach. Finally, the selected cermet powder was deposited on a Ti-6Al-4V substrate using HPCS, and the resulting coatings were evaluated through SEM, EDS, and XRD analyses under different CS conditions. The optimized 95 wt.% AlCoCrFeNi+5 wt.% TiC cermet coating exhibited an average thickness of 24.20 ± 6.81 μm with a deposition efficiency of 29.29 %, demonstrating the successful fabrication of an HEA–ceramic composite coating via HPCS. Its mechanical performance was evaluated through Nano indentation testing which shows hardness of 7.34 ± 1.96 GPa and 123.39 ± 17.86 GPa Elastic Modulus of the coating. This study correlates feedstock powder design and characterization, with numerical modeling and successful deposition of HEA–TiC cermet coatings on hard Ti-6Al-4V substrates, providing a comprehensive framework for optimizing material selection and HPCS processing conditions.