Nb-Cu metallic composite: SPS preparation, microstructure and mechanical properties

This study investigates the effects of milling time and sintering temperature on the properties of Nb-Cu, prepared by high-energy milling and spark plasma sintering (SPS). X-ray Diffraction (XRD), laser scanning confocal microscopy and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS) were used to characterize microstructural changes and discuss their influence on the relative density, microhardness, and electrical conductivity of the composite. The samples with higher milling time and temperature had higher values of density. Conductivity reached a maximum value of 1.78 x 10-7(m?)-1. The hardness reached was 473.84 HV. Superconductivity analysis revealed a two-stage transition in resistance for Nb-Cu, with drops at 11.2 K and 6.6 K, indicating Cu-Nb interaction effects. This behavior contrasts with the single transition observed in pure Nb. Principal Component Analysis (PCA) confirmed a strong positive correlation between microhardness, relative density, and electrical conductivity, indicating that these properties are primarily influenced by sintering temperature.