Electric Resistance Sintering of Al-TiO 2 -Gr Hybrid Composites and Its Characterization

In the present work, Al-TiO 2 -Gr hybrid composites were fabricated through a sustainable manufacturing approach, i.e., ERS (Electric Resistance Sintering) technique. In this experimental work, sintering is performed in a high-density graphite die, which also works as a heating element. The green compacts kept in the graphite die are sintered in two ways simultaneously (conduction and resistance heating). This facilitated the accomplishment of the sintering at a lower current (300–500 A). The aluminum (Al) was reinforced with 9 wt. % TiO 2 (rutile) nanoparticles and 3 wt. % graphite microparticles to synthesize a self-lubricated high wear resistance material. Mechanical properties such as density, hardness, and wear loss of the Al-TiO 2 -Gr hybrid composite were investigated. Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were performed for microstructural investigation. The experiments were performed according to the Taguchi design of the experiment, where three input process parameters (temperature, holding time, and sintering load) were taken to fabricate the Al-TiO 2 -Gr composite. The sintering temperature of 550 °C resulted in the maximum value of mean sintered density (approx. 2.45 gm/cm 3 ). The holding time of 10 min for the sintering resulted in the maximum value of mean sintered density and mean hardness (HRB 53.5). The mean value of wear loss was found to be minimum for the composites sintered at 600 °C for 10 min. The maximum value of the sintering load (800 N) revealed better density and hardness. Worn surfaces and wear debris were also analyzed with the help of SEM images. The sintering temperature of 600 °C resulted in imparting more wear resistance which was proved by smooth surfaces, micro-cutting, and fewer crates, grooves, and smaller pits.