Fabrication of in situ Cu/SiC composites using multi-pass friction stir processing: Evaluation of microstructural, porosity, mechanical and electrical behavior

In this study, multi-pass friction stir processing (MFSP) is used for improvement of microstructural and mechanical properties of in situ Cu/SiC composites. Field emission scanning electron microscopy and optical microscopy images indicate that multi-pass FSP notably enhances the separation and dispersion of SiC particles and also reduces the grain size in the composite matrix, SiC particles size and porosity contents. According to the results, higher microhardness values and remarkably enhanced tensile properties were caused by higher number of FSP passes. It was also found that the average friction coefficients of composites fabricated by multi-pass FSP were noticeably reduced compared to the pure copper. Addition of SiC particles led to enhancement of electrical resistivity of pure copper. A negligible difference between the electrical resistivity of composites fabricated by 1, 4 and 8-pass FSP was also detected.