Characterization of In-Situ Cu-TiH2-C and Cu-Ti-C Nanocomposites Produced by Mechanical Milling and Spark Plasma Sintering
Résumé
This study focuses on the fabrication and microstructural investigation of Cu-TiH2-C and Cu-Ti-C nanocomposites with different volume fractions (10% and 20%) of TiC. Two mixtures of powders were ball milled for 10 h, consequently consolidated by spark plasma sintering (SPS) at 900 and 1000 degrees C producing bulk materials with relative densities of 95-97%. The evolution process of TiC formation during sintering process was studied by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM). XRD patterns of composites present only Cu and TiC phases, no residual Ti phase can be detected. TEM images of composites with (10 vol % TiC) sintered at 900 degrees C show TiC nanoparticles about 10-30 nm precipitated in copper matrix, most of Ti and C dissolved in the composite matrix. At the higher sintering temperature of 1000 ffi C, more TiC precipitates from Cu-TiH2-C than those of Cu-Ti-C composite, particle size ranges from 10 to 20 nm. The hardness of both nanocomposites also increased with increasing sintering temperature. The highest hardness values of Cu-TiH2-C and Cu-Ti-C nanocomposites sintered at 1000 ffi C are 314 and 306 HV, respectively.