Effect of Y2O3 Nanoparticles on the Evolution of the Microstructure and Mechanical Properties of Severely Plastic Deformed Cu Sheets During Friction Stir Processing

Pure Cu sheets with severe plastic deformation were obtained using constrained groove pressing (CGP) and subjected to different passes of friction stir processing (FSP) with and without yttria nanoparticles. The fine grain structure of the CGP-treated samples underwent rapid grain growth during 1-pass FSP without nanoparticles. The addition of yttria particles resulted in a very fine-grained structure in the stir zone (SZ) with a high hardness value and the lowest weight loss during the wear test. Applying 3 passes of FSP resulted in homogeneous dispersion of reinforced particles in both the annealed and CGP processed samples. The SZ of the sample that was processed with CGP and 3-pass FSP in the presence of yttria had a finer grain with higher strength and wear resistance than the FSP-treated annealed samples.