Thermal stability of grain structure and material properties in an annealing twinned Ag–4Pd alloy wire

•An annealing twinned wire has been produced for high electrical conductivity and low cost.•The electrical resistivity decreased from 3.5 to 2.9 μΩ cm after aging at 600 °C for 30 min.•The grain size in the annealing twinned wire increased much more slowly.•The mechanical properties of annealing twinned wire are higher than conventional wire. An annealing twinned Ag–4Pd binary alloy wire has been produced as an alternate material for a previously developed Ag–8Au–3Pd ternary alloy wire to meet requirements for high electrical conductivity and low cost. The electrical resistivity of this annealing twinned Ag-alloy bonding wire decreased drastically from the original value of 3.5μΩcm to about 2.9μΩcm after aging at 600°C for 30min. The decrease in electrical resistivity became moderate with longer aging times. In contrast to the apparent increase in grain size in a conventional Ag–4Pd wire during aging at 600°C for various times, the grains in this annealing twinned wire grew much more slowly. The breaking load and elongation of this annealing twinned Ag–4Pd wire are also higher than those of conventional wire. The conventional grained Ag–4Pd wire has a slightly higher electrical resistivity of 3.7μΩcm than that of annealing twinned wire. However, the more rapid grain growth in the conventional grained Ag–4Pd wire led to a lower electrical resistivity than that of annealing twinned wire during aging process.