Production, characterisation and utilisation of grinding swarf/feedstock for synthesis of metal matrix composite through powder metallurgy process: A short communication

This article is intended to demonstrate an innovative idea wherein trash of grinding swarf could be converted into treasure of metal matrix composite (MMC). The grinding swarf produced during the slitting operation of structural-mild steel using a high-speed cut-off saw was characterised for morphology, mineralogy and rheology. Scanning electron microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and X-ray diffraction (XRD) characterisation of the grinding swarf and MMC were carried out to deliberate their morphological, elemental and microstructural attributes. The rheological attributes of the swarf were quantified through the Hausner ratio, Can's index and angle of repose. The rheological, microstructural, morphological and elemental analysis of the grinding swarf exhibited their suitability to be used as feedstock for the powder metallurgy (P/M) process. Since the feedstock contained a mixture of soft steel chips and harder iron oxide layered spherical particles, the feedstock was processed through the P/M process to synthesise the MMC. The feedstock was compacted in a hardened steel die using a uniaxial hydraulic press at 200 MPa pressure. Subsequently, the sintering of the green compact was carried out at 1150 degrees C in an inert environment. The green and sintered densities of the MMC were evaluated through the conventional and Archimedes principle respectively. The green and sintered densities were found as 4.78 +/- 0.01 g/cm(3) and 5.12 +/- 0.01 g/cm(3)' respectively. Further, the average microhardness of the MMC evaluated by Vicker's hardness tester was 336 Hv(0.05). The overall physio-mechanical properties of the composite were revealed by a specific microhardness as 65.62, which is even better than some of the aluminium-MMCs.

Automated summary

This article demonstrates an innovative idea of converting grinding swarf into metal matrix composite (MMC). The grinding swarf produced during a specific operation was thoroughly characterized and found suitable for the powder metallurgy process. By compacting and sintering the feedstock composed of steel chips and iron oxide particles, the MMC with excellent physio-mechanical properties was synthesized.