Dry ball milling and wet ball milling for fabricating copper–yttria composites

Yttria-reinforced copper matrix composites were prepared by dry ball milling (DBM) and wet ball milling (WBM), respectively, followed by spark plasma sintering (SPS). It is to determine which milling process is better for fabricating Cu–Y₂O₃ composites. It is found that Cu–Y₂O₃ composites synthesized by DBM exhibit better densification, mechanical and electrical properties than those by WBM. Less agglomeration of reinforcements in the bulk composites by DBM is responsible for the better performances. To further understand the reason of less agglomeration of Y₂O₃ in the bulks by DBM, morphologies of prepared powders were investigated and analyzed. Higher ball’s impact energy and the formation of copper oxide on the matrix surface during DBM process contribute to small matrix particles, which is beneficial for less agglomeration.