Nanocrystallization and Dissolution of Immiscible Powder Alloys Using High Pressure Torsion
Precompacts out of immiscible systems CuCr (75/25 wt%) and WCu (80/20 wt%), respectively, were made by pressing mixed powders and sintering. By applying different strains and hydrostatic pressures of HPT at room temperature, disc-shaped samples with a diameter of 8 mm were produced. They were investigated by Light Microscopy, Scanning-Electron Microscopy using Back-Scattered Electrons, and X-ray Line Profile Analysis. In addition, Vickers microhardness data were collected. Both systems showed the highest microhardness at a shear strain of about γ = 170. The density (for the case of Cu25Cr) of the consolidated material could be increased to the theoretical value. Microhardness and grain sizes were studied individually for each of the phases, too.
Jing Tao Wang, Roberto B. Figueiredo and Terence G. Langdon
S. Kahofer et al., "Nanocrystallization and Dissolution of Immiscible Powder Alloys Using High Pressure Torsion", Materials Science Forum, Vols. 667-669, pp. 151-156, 2011