Factors Affecting the Coarsening and Agglomeration of Alumina Particles in Cu–Al2O3 Composites Prepared with Internal Oxidation

Alumina dispersion strengthened copper (DS‐Cu) shows excellent properties regarding mechanical behavior, thermal stability, thermal conductivity, and radiation resistance, making it a promising candidate of heat sink materials for fusion divertor applications. Compared to mechanical alloying, traditional internal oxidation route has merits of reduced contamination and capability of mass production. However, the tailoring of oxide particles, either intra‐ or intergranular, is essential to further improve the properties of DS‐Cu fabricated through internal oxidation route. Herein, the origins of coarsening and agglomeration of alumina particles are uncovered through a dedicated combining investigation between powder metallurgy and Rhines‐pack method, and contributing factors, such as grain boundaries, diffusion distance, concentration of Al, atomization, and the existence of water vapor, are identified. The effects of Ti doping on tailoring the size, shape, and distribution of intergranular and intragranular particles are demonstrated also. This study is of significance for the further improvement of properties of DS‐Cu fabricated with the combination of powder metallurgy and internal oxidation.