- [English]
- Microstructure and Properties Comparison of Pure Cu and Cu-5 wt.% Al2O3 Composite Processed by Spark Plasma Sintering
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Dinh Van Cong, Dong-Wan Lee, Su-Wan Lee, Nguyen Minh Thuyet, Nguyen Viet Hoang, Jin-Chun Kim
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Received December 3, 2025 Accepted February 25, 2026 Published online February 26, 2026
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DOI: https://doi.org/10.4150/jpm.2025.00472
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 Abstract
- 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 oC 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.
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KPMI
