Comparative analysis of mechanical and tribological properties of hypereutectic Al-Si piston alloy and novel Al6082 metal matrix composites

Abstract

Aluminium alloys, particularly hypereutectic Aluminium-silicon (Al-Si) types with silicon content above 12.6%, are extensively used in high-performance automotive and aerospace components such as pistons, cylinders, and engine blocks due to their excellent thermal and mechanical properties. Despite their widespread application, detailed data on the chemical composition and mechanical performance of commercial piston alloys remain limited. This study presents a comparative evaluation of a commercial hypereutectic Al-Si piston alloy and a stir-cast Al6082-based metal matrix composite (Al-MMC) reinforced with nano-sized ZrO₂ and nano marble dust, aiming to assess the feasibility of the developed composite as an alternative piston material for demanding engineering applications. Elemental composition of the AlSi alloy was determined using X-ray fluorescence (XRF), while phase and microstructural analyses were conducted through X-ray diffraction (XRD). Mechanical characterization included microhardness, tensile strength, and surface roughness measurements. The hypereutectic Al-Si piston alloy exhibited a microhardness of 202.87 HV, tensile strength of 212.63 MPa, and surface roughness of 1.45 µm. In comparison, the Al-MMC demonstrated 191.60 HV hardness, higher tensile strength of 245.26 MPa, and surface roughness of 1.67 µm. Tribological performance under dry sliding conditions was evaluated using specific wear rate (SWR) and Coefficient of Friction (COF) as key indicators. Surface morphology and wear mechanisms were further analyzed using Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray Spectroscopy (EDX). This comprehensive study provides valuable insights into material behavior and establishes a performance benchmark for future aluminium-based composites in automotive applications.