A Study on the Microstructure and Properties of Cu-Fe-Mg-Ti Alloys Based on Composition Regulation

This study systematically investigates how Fe-Ti atomic ratios (1:1, 1:2, and 2:1) influence the microstructure, mechanical properties, and softening resistance of Cu-Fe-Mg-Ti alloys under fixed total Fe + Ti content. Through hardness testing, electrical conductivity measurements, and multiscale characterization (optical microscopy, scanning/transmission electron microscopy, and X-ray diffraction), we reveal a previously unreported phenomenon: Ti-dominated ratios (1:2) enable superior strength-conductivity synergy. After 70% cold rolling and 550 °C aging, the alloy with a 2:1 Fe/Ti ratio exhibits peak hardness (166.5 HV) and conductivity (64.1% IACS), outperforming both 1:1 (173.9 HV, 51.3% IACS) and 1:2 (189.5 HV, 44.2% IACS) counterparts. Critical microstructure analysis confirms that increased Ti content promotes high-density Fe₂Ti nanoprecipitation (5-15 nm) with coherent interfaces, enhancing strength while mitigating electron scattering. This work establishes atomic ratio optimization as a novel strategy to break the traditional strength-conductivity trade-off in copper alloys, providing a 21% hardness improvement over conventional Fe-Ti systems without sacrificing essential electrical performance.