Microstructural and mechanical characteristics of Cu-Cu₂O composites compacted with pulsed electric current sintering and hot isostatic pressing

This paper reports the influence of applied sintering process – pulsed electric current sintering (PECS) and hot isostatic pressing (HIP) – on the microstructure and mechanical properties of Cu–Cu2O composites. In PECS fine-grained structure was obtained while in HIPing the grain growth was more noticeable, mostly due to the longer process time. The studies also showed that Cu2O-phase distributed in Cu-matrix increased microhardness; at a fixed grains size Cu–Cu2O structure had higher hardness than Cu so that 20% higher microhardness was obtained when Cu2O was doubled from 19.1 to 37.2 vol%. At best, 99.1% density with 690 nm grain size and 1.35 GPa hardness were achieved by PECS whereas by HIP the same density with 1860 nm grain size gave 1.02 GPa hardness. The grain growth and the effect of second phase clustering on the grain growth were evaluated experimentally.