Exploration of morphological and mechanical behaviour of Al2O3/Al-Mg-Cr-Zn alloy composites with Al6O13Si2 addition

Abstract

Al-Mg-Cr alloys have inferior heat resistance compared to other aluminium alloys, however hard ceramic reinforcement and processing can improve it. The current work aimed to synthesise composites of mullite (Al6O13Si2)-reinforced Al-Mg-Cr-Zn alloy with different weight proportions using the squeeze casting process and its morphology and mechanical properties were examined using SEM and mechanical tests. It was observed that Al6O13Si2 is uniformly distributed in the matrix alloy indicating no residual pores. The eutectic particles of Al2SiC Mg17Al2.Mg2Si are precipitated along grain boundaries refining grain size 15–25 μm. Owing to enhanced grain refinement and heat treatment process, the mechanical properties, hardness (18.31 %), tensile (21.12 %), compressive (24.56 %), flexural (25.64 %) and impact strength (28.87 %) improved. Hard reinforcement nucleates oxide formation, improving corrosion resistance 29.90 %, while aluminium silicate makes the composite's harder particles more resistant to abrasive stress, lowering material loss.