Effect of eggshell waste and B4C particles on the mechanical and tribological properties of Al7075 alloy developed by friction stir processing

Abstract

The waste and hazardous materials have the potential to be used as reinforcement materials in the development of metal matrix composites (MMCs). In this regard, aluminium based MMCs have increased demand than conventionally manufactured materials due to their high strength to weight ratio, low cost and wear resistance. In this work, an attempt is made to develop the surface composite of Al7075 alloy by utilizing carbonized, ball-milled waste eggshell powder (ESP) and B4C particles as reinforcements through the solid-state friction stir processing technique. Three different samples are developed with volume percentages of 2%, 4%, and 6% of ESP/B4C particles. The developed surface composites are validated by light microscopic images, FE-SEM images linked with EDS mapping and distribution of reinforced particles. The microstructural image shows the uniform distribution of the reinforced particles. The specimens are also characterized by their mechanical and tribological properties like tensile test with fracture analysis, hardness test and wear loss supported by worn-out surface analysis. The result revealed that while increasing the reinforcement volume percentage, an increase in mechanical properties of the developed composites is found. The maximum ultimate tensile strength (UTS) and Brinell hardness number (BHN) obtained in the study are 355 MPa and 167 BHN, respectively for the developed composites AA7075/ 6% eggshell/B4C. The minimum wear loss was observed to be 2.5 to 6.2 × 10–3 g at a sliding distance of 600 m for a 6% reinforced sample.