Microstructures and thermal properties of Ag-CNT/Cu composites fabricated by friction stir welding

Abstract

Friction stir welding (FSW) is a novel solid-state welding technique. This process has many advantages, such as no consumable requirement, low distortion, low shrinkage, and excellent mechanical properties. Recently, FSW has been successfully used to fabricate metal matrix composites (MMCs), as the process overcomes environmental problems caused by other MMC fabrication processes. In previous studies, the goal was to reinforce the mechanical properties of base materials. In this study, the FSW technique and Ag-decorated carbon nanotubes (Ag-CNTs) were used to enhance the thermal properties of copper, and the microstructures of joints of Ag-CNT-reinforced copper fabricated by FSW were evaluated. The microstructures were analyzed using an optical microscope, and the presence of Ag-CNT in the joint was observed using a scanning electron microscope. Additionally, we confirmed the distribution of Ag-CNTs by electron probe microanalyzer, and the thermal properties of joints were evaluated by laser flash analysis. The Ag-CNT-reinforced Cu composites fabricated by FSW have improved thermal properties compared with conventional copper MMCs.