Abstract
<jats:p>Ag-Ti3SiC2 composites are promising electrical contact materials, yet the atomic-scale interfacial behavior between Ti3SiC2 and Ag remains poorly understood. Here, first-principles calculations were performed to investigate the interfacial stability, electronic structure, and alloying effects at the Ti3SiC2(0001)/Ag(111) interface. Surface-energy calculations for six terminations of Ti3SiC2(0001) show that the TiC(TiC) termination is preferred at low carbon chemical potential, whereas the TiC(TiSi) termination becomes the most stable once ΔμC exceeds -1.50 eV. Eighteen interface models combining the six terminations with three stacking sequences (OT, MT, and HCP) were constructed, and their work of adhesion (Wad) and equilibrium spacing (d0) were determined by the Universal Binding Energy Relation and full structural relaxation. The HCP stacking is preferred for all terminations, and the C(TiC)-terminated HCP interface is the most stable, with Wad = 9.25 J/m2 at d0 = 1.2 Å; relaxation enhances Wad by 10-75%. Charge density, charge density difference, and partial density of states analyses reveal that the interfacial bonding is dominated by C 2p-Ag 4d hybridization accompanied by electron transfer from Ag and Ti atoms to the interfacial C atoms, which accounts for the adhesion hierarchy. Substitutional alloying with Cu, Ni, Zn, and Cr is energetically most favorable within the interfacial Ag layer, and Wad increases in the order Cu &lt; Zn &lt; Ni &lt; Cr, reaching 11.0 J/m2 for interfacial Cr, an enhancement of 19% over the pristine interface. The strengthening correlates directly with the filling of the dopant 3d band. These results provide theoretical guidance for the interfacial design of high-performance Ag-Ti3SiC2 electrical contact composites.</jats:p>