Ni_xCr (x = 2 and 3): the top choice for enhancing bonding performance of ZTA–Fe interfaces demonstrated by first principles calculations

To obtain the appropriate additives and overcome the challenge of inadequate bonding between ZTA particles and the iron matrix, the adhesion strength, interfacial stability, fracture mechanism, tensile strength, and electronic structures of Ni_xCr (x = 2, 3)–Al₂O₃ interfaces were calculated using first principles calculations and first principles molecular dynamics calculations. The metal–oxygen stacking Ni_xCr–Al₂O₃ interfaces offer exceptional bonding strength and thermostability under most conditions, but high temperatures and inadequate oxygen environments will enhance the stability of the metal–metal stacking interfaces. The Griffith theory and first principles tensile tests suggest that the initial fracture was observed at the metal–metal interfaces bonded through metallic Ni/Cr–Al bonds, however, cracks will develop within the bulk rather than at the metal–oxygen interfaces, which are bonded through mixed covalent/ionic Ni/Cr–O bonds. Furthermore, when comparing the adhesion strength and thermostability between Ni_xCr–Al₂O₃ and Ni_xTi_y–Al₂O₃ interfaces, it is evident that Ni_xCr–Al₂O₃ interface is the most suitable option, especially the Ni₂Cr intermetallic, as it outperforms Ni_xTi_y–Al₂O₃ interface in terms of balancing the interfacial bonding strength, stability, and tensile strength.