Microstructure and elastic constants of AlTiVMoNb refractory high-entropy alloy coating on Ti6Al4V by laser cladding

AlTiVMoNb refractory high-entropy alloy coatings (RHEACs) prepared by laser cladding have good metallurgical bonding with Ti6Al4V (TC4) substrates. X-ray diffraction data indicate that the coating structure is a body-centered cubic (BCC) phase, and the laser cladding process can refine the microstructure of the coating and reduce the value of the lattice constant a to achieve fine-grain strengthening. Ab initio model was established by the Exact Muffin-tin Orbitals combines Coherent Potential Approximation (EMTO-CPA) theory, the reflex power diffraction of X-ray and elastic constants of the coating was calculated. The experimental x-ray data and the calculation results are the same. The stress-strain method and Voigt-Reuss-Hill approximation obtained elastic constants and module. The elastic constant C-ij of the RHEACs conforms to Pugh's principle of mechanical stability and has suitable anisotropy and ductility. Notably, the calculated results of hardness and Young's modulus are consistent with the trend of NanoBlitz 3D nanoindentation test data.