Adhesion property of AlCrNbSiTi high-entropy alloy coating on zirconium: experimental and theoretical studies

Experimental scratch tests and first-principles calculations were used to investigate the adhesion property of AlCrNbSiTi high-entropy alloy (HEA) coatings on zirconium substrates. AlCrNbSiTi HEA and Cr coatings were deposited on Zr alloy substrates using multi-arc ion plating technology, and scratch tests were subsequently conducted to estimate the adhesion property of the coatings. The results indicated that Cr coatings had better adhesion strength than HEA coatings, and the HEA coatings showed brittleness. The special quasi-random structure approach was used to build HEA models, and Cr/Zr and HEA/Zr interface models were employed to investigate the cohesion between the coatings and Zr substrate using first-principles calculations. The calculated interface energies showed that the cohesion between the Cr coating and the Zr substrate was stronger than that of the HEA coating with Zr. In contrary to Al or Si in the HEA coating, Cr, Nb, and Ti atoms binded strongly with Zr substrate. Based on the calculated elastic constants, it was found that low Cr and high Al content decreased the mechanical performances of HEA coatings. Finally, this study demonstrated the utilization of a combined approach involving first-principles calculations and experimental studies for future HEA coating development.