Mechanical Property Characterization of Cryo-Rolled Copper by Miniaturized Disk Bend and Nanoindentation Technique

The present study reports mechanical behavior of severe plastically deformed pure Cu under cryogenic conditions by miniaturized disk bend test (MDBT) and nanoindentation technique. MDBT is a useful technique to determine mechanical property of miniature samples under multiaxial state of stress. The samples were severely deformed by cryo-rolling upto 75% and 95% reduction. Microstructure evolution of cryo-rolled samples has been characterized using optical and EBSD technique. MDBT was performed on cryo-rolled 10-mm disk of ~200-μm thickness. Nanoindentation tests were also performed on the cryo-rolled samples. The hardness values obtained from nanoindentation tests were compared with yield stress obtained from MDBT. The present study established a good quantitative correlation between the two techniques. Mechanical dynamic parameters; strain rate sensitivity (m) and activation volume (V*) determined by MDBT and nanoindentation techniques showed close agreement in the results.