Preparation of Cu Powders with Electrical Explosion of Wires and Their Size-Dependent Mechanical Properties

In this paper, spherical and regular Cu powdersCu powder without satellite spheres were prepared by the electrical explosion of wireElectrical explosion of wires method. Based on the Newton cooling law, the dependence of the cooling rateCooling rate on powder size was obtained, showing that the cooling rateCooling rate reduced with increasing the powder diameter. Accordingly, Cu powdersCu powder with a diameter of ~50 μm and 100 μm were selected to address the effect of cooling rateCooling rate on the mechanical propertiesMechanical properties of a single powder by using nanoindentation. For the powder with a diameter of 100 μm, the hardnessHardness and modulusModulus were 2.0 GPa and 61.7 GPa, respectively, while they are 2.2 and 93.0 GPa, respectively, for the powder with a diameter of 50 μm. When the powder diameter decreases, the cooling rateCooling rate enlarges, and the grain size is refined, leading to the improvement of the mechanical propertiesMechanical properties of the Cu powderCu powder.