Evaluation of Vickers Micro Hardness of Solution Heat Treated (SHT) Al6061/2%Gr/0 6%Al₂O₃ Composites for Piston Applications

Abstract

This research seeks to evaluate the Vickers micro hardness of Solution Heat Treated (SHT) Al6061/2%Gr/0-6% Al₂O₃ composites, and delve into their prospect for piston applications. Al₂O₃ was used as reinforcement in Al6061/Gr composites to improve mechanical properties. Solution heat treatment was carried out at different temperatures (400°C, 500°C, 600°C) and durations (1, 1.5, 2 hours), followed by ageing at varying temperatures (150°C, 175°C, 200°C) and durations (2, 4, 6 hours). The factors and optimal levels were identified using Minitab Results. The Taguchi L9 Orthogonal Array in Minitab was run using the factors and levels. The hardness properties were evaluated through Vickers micro hardness tester. After completing the experiments, the measured values for each trial of the hardness were entered into Minitab. Then the S/N ratios were analyzed in Minitab via Analyze Taguchi Design sub-menu and selecting the Signal-to-Noise Ratio (S/N) response option for the desired outcome of Vickers hardness. The S/N ratio type was set to "Larger-the-Better" for hardness. The Minitab was used to output the mean S/N ratios for each level of each factor and the highest S/N ratio for each factor, which represents the optimal level for that factor, was identified and interpreted. The results reveal significant improvements in hardness with higher Al₂O₃ content, and thus offer insights into their suitability for high-stress applications, such as pistons.