With the massive penetration of electronics into human life, higher demands are placed on electrical contacts. Among them, the lifetime of electrical contacts and safety are the most concerning. In this research, Al₂O₃-Cu/25Mo5Ta and 0.5Y₂O₃/Al₂O₃-Cu/25Mo5Ta composites were prepared by using ball milling and powder metallurgy methods. The two composites were subjected to 10,000 contact opening and closing electrical contact experiments and the arc duration and arc energy were analyzed. The results show that the addition of Y₂O₃ has a slight effect on the mechanical properties of the Al₂O₃-Cu/25Mo5Ta composites but has a significant effect on the electrical contact performance. Y₂O₃ can reduce the mass loss of the electrical contacts during the electrical contact process, which prolongs their service life. The addition of Y₂O₃ decreased the average arc duration and arc energy of the electrical contact material by 21.53% and 18.02%, respectively, under the experimental conditions of DC 30 V, 10 A. TEM results showed that nanoscale YTaO₄ with excellent thermal stability was generated during the sintering process, which has a positive effect on the electrical contact performance of the composites.

Copper alloys with a combination of good electrical conductivity and mechanical properties are widely used in automotive electronics, large-scale integrated circuits, and other fields. In this study, a new type of Cu–Ni–Si alloy with added trace elements of Co and Cr was fabricated. Hot compression tests of this alloy at different temperatures and strain rates were conducted using a Gleeble-1500D simulator. Then, the microstructure transformation and precipitation behaviors of the Cu-1.1–Ni-0.7–Co-0.45–Si-0.3Cr alloy were studied during a hot deformation process. The results show that the hot deformation behavior of the Cu-1.1–Ni-0.7–Co-0.45–Si-0.3Cr alloy includes continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). The intensity of the texture in the microstructure is decreased, and the randomness of the texture in the microstructure is increased together with the recrystallization progress. The degree of recrystallization of the new Cu-1.1–Ni-0.7–Co-0.45–Si-0.3Cr alloy is increased when the hot deformation temperature rises. Additionally, the results indicate that there are two types of precipitates which are formed in the alloy during the hot deformation process. These two precipitates can pin dislocations and grain boundaries, and therefore, they significantly improve the hot compression resistance of the Cu-1.1–Ni-0.7–Co-0.45–Si-0.3Cr alloy.