Realization of high resistivity and low-temperature coefficient of resistivity in Fe-20Mn-11Al-5Cr-1C-0.01B alloy through microstructure control

Metallic alloys typically follow the Mooij rule, which describes the trade-off relationship between electrical resistivity and the temperature coefficient of resistivity (TCR). Fe-20Mn-11Al-5Cr-1C-0.01B (mass%) alloy, annealed at temperatures ranging from 600 °C to 1000 °C, deviates from the Mooij rule and exhibits excellent electrical properties, including high electrical resistivity and low TCR. X-ray diffraction measurements revealed that the constituent phases of the alloys are α-, γ-, κ-, and carbide phases. TCR is significantly influenced by the fraction of α-phase, the concentration of solute elements in the matrix phases, magnetism, and the quantity of precipitated carbides in the matrix. The results indicate that controlling the microstructure of metallic alloys can achieve high resistivity and low TCR, thereby deviating from the Mooij rule. • Electrical resistivity strongly depends on microstructure such as fcc/bcc phase ratio and volume fraction of carbides. • Microstructure-controlled Fe-20Mn-11Al-5Cr-1C-0.01B alloy exhibits high resistivity (206 μΩ cm) while maintaining a low TCR (54 ppm/°C). • TCR can be controlled by adjusting the effects of weak localization of electrons and the ferromagnetic phase.