Strengthening of Cu through grain refinement by friction stir processing

Abstract

Friction stir processing (FSP) can be used as a tool to refine grain. Present investigation was conducted to observe the effect of FSP on microstructure and mechanical properties of copper. As such, a 6 mm thick plate was processed for the investigation. The processed part (4 mm) was milled by using NC controlled vertical milling machine for the analyzation. During the process, rotational speed was varied from 600 RPM to 1800 RPM while keeping traverse speed constant at 40 mm/min. The initial coarse grain of copper having average grain size of 28 μm changed to 6, 8 and 11 μm at 600, 1200 and 1800 RPM respectively. At 600 RPM, hardness and strength were observed to be 21 % and 29 % higher than that of as received copper. The hardness and strength increased with decreased grain size according to Hall-Petch relation. © 2023 Author(s).