Improvement the thermal stability and mechanical properties of ODS Cu alloy by forming composite oxide dispersion

Abstract

Oxide dispersion strengthened (ODS) Cu alloy is a kind of structural material with high thermal conductivity and high stability. It is promising to maintain mechanical integrity under thermal conductivity and high temperature conditions. These excellent properties are directly or indirectly attributed to the ultra-high number density of nano oxide particles, which act as a strong barrier for grain growth, dislocation slip and grain boundaries (GBs) slip. In this study, Cu-Cr-Y-Al-Ti-Si and ODS Cu-Cr-Y-Al-Ti-Si alloys were prepared by combining mechanical alloying with spark plasma sintering (SPS) technology. The influence of Cu₂O on the microstructure, mechanical properties, and thermal stability of the Cu-Cr-Y-Al-Ti-Si alloy were investigated. Both alloys exhibited a heterogeneous mixture of coarse and fine grain structures. However, the addition of Cu₂O led to grain refinement and the precipitation of a high density of uniformly distributed, nano-sized oxide particles throughout the copper matrix. Compared to the Cu-Cr-Y-Al-Ti-Si alloy, the ultimate tensile strength of the ODS Cu-Cr-Y-Al-Ti-Si alloy escalated from 409 MPa to 482 MPa, while the elongation slightly decreased from 17.2 % to 15.2 %. The ODS Cu-Cr-Y-Al-Ti-Si alloy also demonstrates a room temperature thermal conductivity equivalent to 62.8 % of pure copper, and exhibits ultra-high microstructural stability after annealing at 600 °C for 100 h. The outstanding strength, ductility and high-temperature stability are primarily owing to the coherent nano-sized Y-X-O (X = Al, Ti, Si) particles dispersed in the ultra-fine grain copper matrix. These findings indicate that by integrating component design and process optimization, it is possible to effectively and efficiently produce ODS Cu-Cr-Y-Al-Ti-Si alloy, which holds promising application prospects in structural materials for nuclear fusion reactors.