Achieving resistivity and thermal stability balance in Cu‑xMn‑3Ni-based alloy resistors for smart energy meters

High-stability precision resistance alloys are core functional components for DC shunts and high-end smart energy meters. The synergistic control of low resistivity and low temperature coefficient of resistance (TCR) is critical for their service performance under high power conditions. Cu‑Mn‑Ni‑based alloys offer a balanced combination of electrical conductivity and thermal stability, and alloying and heat treatment are the key technical approaches for optimizing their properties. In this work, the effects of Mn content and quenching process on the microstructure, electrical resistivity and TCR of hot‑rolled Cu‑ x Mn‑3Ni-based alloys were investigated. With increasing Mn content, the preferential orientation of the (311) plane becomes stronger, while that of the (111) crystal plane weakens, and the resistivity increases whereas the TCR decreases. As the quenching temperature rises from 500 to 800 °C, the dominant factor governing texture in the Cu-17Mn-3Ni-based alloy evolution changes from internal‑stress‑driven thermodynamic stability to kinetic resistance of grain boundary migration, and the (220) plane becomes the dominant preferred orientation. After quenching at 750 °C followed by aging at 260 °C, the effective elimination of residual stresses enables the alloy to possess both appropriate electrical resistivity (0.46 μΩ m) and excellent thermal stability (TCR = 29 ppm/°C). This work highlights that the composition synergistic heat treatment provides a feasible strategy to develop precision resistance alloys with balanced resistivity and temperature stability.