Extending the upper limit of volumetric fraction of oxides in ODS-Cu fabricated with internal oxidation via element doping

Abstract

In general, when the oxide content is controlled within 5 wt%, increasing the content of oxides is crucial for improving the strength, hardness, and wear resistance of oxide dispersion strengthened copper alloy (ODS-Cu). However, the oxide content of commercially available ODS-Cu fabricated with internal oxidation (e.g. Glidcop-60) is limited to 1.1 wt% due to the adverse effects of irregular growth of oxide particles on overall properties when the oxide content increases. In this study, we introduced oxide particles into Cu matrix via internal oxidation of Cu-Al and Cu-Al-Ti alloys using Rhines-pack method. The origin of irregular oxide particles, oxide bands and healing layers formed in the oxidized layer of the ODS-Cu alloys with high oxide content was revealed. Furthermore, it is found that the doping of Ti can effectively suppress the growth of irregular oxide particles and the formation of oxide bands. In the specimens with a Ti/Al molar ratio of 0.28, Ti has a better inhibitory effect on oxide particle coarsening, and this inhibitory effect is more pronounced when ODS-Cu containing higher oxide content. Compared to Cu-0.6 %Al alloy, the average occurrence and length fraction of oxide bands in Cu-0.6 %Al-0.3 %Ti alloy are significantly reduced (by 81 % and 95 % respectively), and the fraction of oxide particles smaller than 20 nm is significantly increased (from 5 % to 76 %). This Ti-doping strategy solves the dilemma in increasing the oxide content in ODS-Cu produced by internal oxidation, and also provides the possibility for industrial production of high oxide volumetric fraction ODS-Cu with internal oxidation.