Effect of preheating on the mechanical and high temperature tribological behaviour of reusing marble dust with aluminium composite

In this paper the effect on the mechanical and tribological behaviour of aluminium alloy (AA 7175) reinforced with marble dust has been studied. The waste powder of marble developed during its processing, which is a huge environmental waste as its disposal is very difficult. The remarkable wear and friction resistant properties of marble dust make to promising material to be used in MMC. Marble dust used untreated may result in defective MMC due to the presence of moisture and chemical contamination. In this article the marble dust was preheated at a temperature of 150 degrees C and 300 degrees C to remove the volatile chemical contamination and moisture. The composite of preheated marble dust and AA 7175 was formed by stir casing. The optical microscopy and XRD analysis was carried for examining the microstructure and dispersion of marble dust particles in the AA 7175 matrix. The microhardness of the MMC sample improved but the tensile strength slightly decreased. The high-temperature tribological study of the developed composite was performed using the Pin-on-Disc tribometer. The scanning electron microscopy was done to study the worn out surfaces. There was considerable improvement in the tribological behaviour of composite prepared by pre-heating the marble dust.