Experimental Comparison of Microwave and Conventional Heat Treatment for Improving Surface Characteristics of Copper, Titanium, and Silicon Carbide Composites

Abstract

Microwave heat treatment is emerging as an energy saving alternative to conventional thermal treatment owing to its fast volumetric heating, short processing time and enhancement in microstructural and mechanical properties of engineering materials. In this paper, the microwave heating efficiency of Copper (Cu), Titanium (Ti) and Silicon Carbide (SiC) composites by powder metallurgy is experimentally studied and compared with conventional heating methods. Composite samples were prepared by uniform powder mixing followed by compaction and thermal treatment using both microwave and conventional processing methods. To understand the effect of the heat treatment method on densification behaviour, microstructural changes and phase formation, the analysed samples were evaluated by density and apparent porosity metrics, optical microscopy and X-ray diffraction (XRD). The experimental results indicated that microwave heat treatment improved the adhesion of particles, pore distribution and densification compared to the specimens treated by conventional heat treatment. Optical microstructural analysis showed some microwave treated samples possessed fairly dense and uniform microstructures, whereas conventionally processed samples exhibited higher residual porosity and localised particle clustering. XRD analysis showed that the phase formation was strongly affected by the reinforcement composition and the Cu–SiC–Ti composites displayed more complex multiphase characteristics than the Cu–Ti composites after microwave processing. Although full densification was not achieved for the studied processing parameters, microwave heat treatment exhibited a great potential to improve the surface integrity and microstructural characteristics, while reducing the processing time. The results suggest that microwave heating can be a feasible alternative for processing advanced powder metallurgy composites, but further optimisation of processing parameters is needed for better densification and mechanical properties.