Improvement of Mechanical Properties of β-AlSiFe Phase by Doping Transition Metals (M = Cr, Mn, V, Ti, and Zr): A First-Principles Study

To enhance and modulate the mechanical properties of the β-AlSiFe (Al₉Si₂Fe₂) phase, we conducted first-principles calculations to investigate the impact of transition metal (M = Cr, Mn, V, Ti, and Zr) doping on the structural stability and mechanical characteristics of the β-AlSiFe phase. The results reveal a transformation in the crystal system from monoclinic to triclinic after M doping. Specifically, Ti-Al-4 (− 0.309 eV) and Zr-Al-6 (− 0.305 eV) exhibit a lower enthalpy of formation compared to pure AlSiFe (− 0.304 eV), indicating their preferential formation over pure AlSiFe. In terms of mechanical properties, the Pugh’s ratio of Zr-Al-6 phase (1.413) demonstrates superior toughness compared to the pure AlSiFe phase (1.352). Moreover, Zr doping inhibits the fracture behavior of the tensile phase, leading to a remarkable 40% increase in strain compared to the pure AlSiFe phase. It is important to note that Zr doping minimally influences orbital hybridization, which is the primary reason for the observed improvement in toughness. This study provides valuable insights for enhancing the ductility of the β-AlSiFe phase and improving the mechanical properties of Al-Si alloys.