This study compares the microstructure and properties of pure Cu and Cu-5 wt.% Al2O3 composites fabricated by spark plasma sintering under strictly identical processing conditions at 800-1000°C. Pure Cu samples achieved near-full densification and exhibited a bimodal grain structure dominated by coarse grains with increasing sintering temperature. In contrast, the composite samples showed lower density and non-monotonic densification behavior, with a minimum relative density at 900°C and significantly refined equiaxed grains due to strong grain-boundary pinning by nano Al2O3 particles. The higher fractions of high-angle boundaries and pronounced orientation disruption were observed in the composite samples, while high-resolution analysis confirmed the presence of grain-boundary Al2O3-rich regions that restricted Cu grain coalescence and continuity of grain boundary migration. X-ray diffraction results confirmed the absence of reaction phases in both materials. Hardness peaked at 900°C for both samples, and the composite samples showed consistently lower hardness due to retained porosity. The apparent electrical conductivity of the composite displays a non-linear temperature dependence, reflecting the competing influences of densification, microstructural recovery, and the insulating nature of Al2O3.

The Jeju Special Self-Government Provincial Government made and has been working on the 'Carbon Free Island Jeju by 2030' Plan. Currently, it has been working on a plan of gradually penetrating (introducing) EVs to Jeju province to realize a carbon-free Jeju Island. In this paper, we made a model equation estimating the electrical energy consumed by EVs in a definite region, and then the number of EVs to be introduced every year according to the ‘penetrating EVs plan’ was estimated. Finally, the electrical energy consumed yearly for the next 10 years by the EVs was calculated.