Studies on Al-Si based hybrid aluminium metal matrix nanocomposites

Abstract

A lightweight Hybrid Aluminium Metal Matrix Nanocomposite (HAMNC) is proposed for brake rotor application in this work. Hypereutectic Aluminium-Silicon (Al-Si) grade LM30 alloy is opted as the matrix with Boron Carbide (nB4C) and Rutile (nTiO2) nanoparticles as reinforcements. The brake rotor samples are produced using ultrasonic squeeze-assisted stir-casting, which is cost-effective and feasible for mass production. The hybrid nanocomposite specimens are fabricated by maintaining 1 wt% of nB4C and by varying TiO2 nanoparticles from 0 wt% to 1.00 wt% in steps of 0.25 wt%. The formulations are subjected to microstructure study and dry sliding wear test. The Field Emission Scanning Electron Micrographs (FESEM) reveal that the stir-casting method combining ultrasonic and squeeze effects aids in the uniform distribution of nano reinforcements. The tribological findings show that the hybrid nanocomposite containing 0.75 wt%. of nTiO2 has an 82.76% lower specific wear rate compared to the parent LM30 alloy. Further, the HAMNC brake rotor is 60% lighter than the brake rotors made of Grey Cast Iron making it a potential replacement material.