On the role of processing parameters in producing Cu/SiC metal matrix composites via friction stir processing: Investigating microstructure, microhardness, wear and tensile behavior

• Published in: Materials characterization 2011-01, Vol.62 (1), p.108-117
• Main Authors: Barmouz, Mohsen, Besharati Givi, Mohammad Kazem, Seyfi, Javad
• Format: Article
• Language: English
• Subjects: BONDING; COMPARATIVE EVALUATIONS; COMPOSITE MATERIALS; COMPOSITES; COPPER; COPPER (PURE); FRACTURES; FRICTION; Friction stir processing; GRAIN SIZE; HARDNESS; MATERIALS SCIENCE; MATRIX MATERIALS; MECHANICAL PROPERTIES; Metal matrix composite; Metal matrix composites; MICROHARDNESS; Microstructure; MICROSTRUCTURES; OPTICAL MICROSCOPY; PARAMETERS; PARTICLES; Particulate composites; Process parameters; PROCESSING; REINFORCED MATERIALS; SCANNING ELECTRON MICROSCOPY; SILICON CARBIDE; SILICON CARBIDES; TENSILE PROPERTIES; WEAR; WEAR MECHANISMS; WEAR RESISTANCE
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2010.11.005

The main aim of this study is to produce copper reinforced metal matrix composite (MMC) layers using micron sized SiC particles via friction stir processing (FSP) in order to enhance surface mechanical properties. Microstructural evaluation using optical microscopy (OM) and scanning electron microscopy (SEM) indicated that an increase in traverse speed and a decrease in rotational speed cause a reduction in the grain size of stir zone (SZ) for the specimens friction stir processed (FSPed) without SiC particles. With the aim of determining the optimum processing parameters, the effect of traverse speed as the main processing variable on microstructure and microhardness of MMC layers was investigated. Higher traverse speeds resulted in poor dispersion of SiC particles and consequently reduced the microhardness values of MMC layers. It was found that upon addition of SiC particles, wear properties were improved. This behavior was further supported by SEM images of wear surfaces. Results demonstrated that the microcomposite produced by FSP exhibited enhanced wear resistance and higher average friction coefficient in comparison with pure copper. Tensile properties and fracture characteristics of the specimens FSPed with and without SiC particles and pure copper were also evaluated. According to the results, the MMC layer produced by FSP showed lower strength and elongation than pure copper while a remarkable elongation was observed for FSPed specimen without SiC particles. [Display omitted] ► Decrease in traverse speed leads to good dispersion of SiC particles in composites. ► No distinct TMAZ in side regions of SZ of FSPed specimens with SiC particles. ► Microhardness of FSPed specimens with SiC particles shows a remarkable increase. ► Reinforcement of Cu with SiC particles improves wear and friction behavior of surface. ► A weak bonding in tensile due to probable agglomeration for SiC containing samples.