Effect of phosphorus on stacking fault energy and tensile properties of oxygen-free copper

Phosphorus, as a critical deoxidation and microalloying element, significantly influences the stacking fault energy (SFE) and tensile properties of oxygen-free copper. In this study, oxygen-free copper samples with varying phosphorus contents were prepared, and the impact of phosphorus content on SFE and its intrinsic relationship with tensile properties and microstructural evolution were systematically investigated using advanced microscopic characterization techniques, including EPMA, EBSD, and TEM. The results indicate that: (1) SFE decreases as phosphorus content increases; (2) Increasing phosphorus content markedly enhances the tensile properties of the samples. Specifically, the tensile strength and elongation of the P1400 sample are 194 MPa and 20.14 %, respectively, representing improvements of 30 MPa and 4.37 % over the P0 sample; (3) The reduction in SFE facilitates the formation of twins and stacking faults, with twin boundaries acting as barriers to dislocation slip. Additionally, the synergistic effects of phosphorus pinning and fine-grain strengthening impede dislocation movement during tensile deformation, thereby enhancing both strength and ductility.