Synthesis and statistical modelling of dry sliding wear of Al 8011/6 vol.% AlB₂in situcomposite

The present study has used response surface methodology (RSM) and central composite design (CCD) for modelling, using wear parameters to predict the wear performance of an Al 8011/6.0 vol.% AlB 2 composite. The effect of applied load and sliding velocity was studied at five levels for a fixed sliding distance. To understand wear behaviour, sliding wear tests were planned according to CCD and performed on a pin-on-disc apparatus at ambient temperature. An analysis of variance (ANOVA) was conducted to show the relative significance of the parameters. A second-order regression model was developed to predict the wear loss and to establish the relationships between wear parameters. Response surface and contour plots were drawn to analyse the wear results. Worn surfaces were examined under scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS) was used to interpret the operative wear mechanisms. Validation tests results show good agreement between experimental and predicted data. As an initial step of this study, AlB 2 particles were reinforced in Al 8011 alloy by an in situ technique to synthesise an Al 8011/6.0 vol.% AlB 2 composite. During synthesis an in situ reaction takes place between molten alloy and inorganic salt KBF 4 at 850 °C, which leads to the formation of AlB 2 particles. The composite was analysed by x-ray diffractometer (XRD) to detect the phases present, while optical and scanning electron microscopy (OM & SEM) were carried out to ascertain morphology and particle distribution. Hardness was evaluated by a Vickers hardness testing machine.