Study on Structures Stability, Mechanical Properties, and Electronic Properties of Alloy Ag–Au–Al: First‐Principles Calculations and Experiments

Abstract

In this paper, the silver–gold–aluminum alloy is prepared, and its effect on the microstructure and properties is observed by changing the content of aluminum. SEM observes the surface morphology, EDS (Energy Dispersive Spectrometer) detects the related tissue composition, and XRD (X‐ray Diffraction) verifies the composition. Ternary alloys are tested for hardness and resistivity. The results show that Ag‐15wt.%Au‐14wt.%Al alloy has the highest hardness. The resistivity test shows that Ag‐15wt.%Au‐18wt.%Al alloy has the lowest resistivity. The change in Al content improves the alloy's mechanical properties and electrical conductivity. This paper uses the first‐principles calculation based on density functional theory to prove the structural stability from the atomic point of view. The mechanical properties, electrical properties, and thermodynamic properties of Ag‐Au‐Al ternary alloys are systematically studied, including elastic constants, elastic modulus (including bulk modulus B, shear modulus G, Young's modulus E, Poisson's ratio ν), Vickers hardness. The mechanical properties of the single crystal are evaluated by Cauchy pressure, Pugh criterion, shear anisotropy factor, and directional Young's modulus, and the Debye temperature is calculated. The calculation results are in good agreement with the experiment. The research in this paper provides a new idea for studying the properties of new bonding wires.

Phase Equilibria of the Ag-Al-Au Ternary System and Interfacial Reactions in the Au-xAg/Al Couples at 450 °C

“…The composition of the light region is Ag-69.60 at.% Al-27.05 at.% Au, which is likely to be the AuAl 2 phase [11]. Han et al also found a small shape with a light color with a phase composition atomic ratio Au to Al close to 1:2, which is determined as AuAl 2 [16]. The composition of the gray region is Ag-39.57 at.% Al-2.92 at.% Au, which is likely to be the Ag 2 Al phase [10].…”