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Item Investigation of impact energy absorption of AA6061 and its composites: role of post-aging cooling methods(Gruppo Italiano Frattura, 2023) Krishna Reddy, G.V.; Naveen Kumar, B.K.; Hareesha, G.; Rajesh, A.M.; Doddamani, S.Al6061 and its composites are widely employed in applications requiring high strength and impact resistance. Heat treatment, particularly ageing, is a well-established method for enhancing the mechanical properties of these composites. However, the influence of post-ageing cooling methods on the impact energy absorption capacity of Al6061 and its composites is not well understood. This investigation aims to examine the impact energy absorption of Al6061 and its composites after ageing at 460°C for 2 hours, employing different cooling methods, including furnace cooling, air cooling, and water cooling. The composites were produced using the stir casting technique with varying weight fractions of graphite and SiC particles based on Taguchi's design of experiments. Charpy impact tests were conducted using a specialised testing machine. The results reveal that the impact energy absorption capacity of the composites is influenced by the cooling method used after the ageing treatment. Furnace cooling demonstrated the highest impact energy absorption capacity compared to the other cooling methods, exhibiting a 28% increase relative to the monolithic aluminium alloy. Furthermore, it was observed that the impact energy absorption capacity of the composites did not improve with an increase in the weight fraction of SiC particles, while the addition of graphite negatively impacted the absorption capacity. © 2023, Gruppo Italiano Frattura. All rights reserved.Item Effects of specimen thickness and compositions on the fracture toughness investigations of Al7075-SiC/Al2O3 hybrid composites utilizing Taguchi optimization and FEA analysis(Springer-Verlag Italia s.r.l., 2025) Bharath, P.B.; Shivakumar, S.P.; Rajesh, A.M.; Prabhuswamy, G.S.; Doddamani, S.The primary objective of this study is to investigate the influence of process parameters on the fracture toughness of aluminium–silicon carbide/alumina particulate composites. The composite is fabricated using the stir-casting method, and the study aims to explore the relationship between process parameters and the resulting mechanical properties of the material. The research seeks to answer how varying process parameters such as reinforcement composition, specimen thickness, and crack length-to-width ratio affect the fracture toughness of aluminium-based hybrid composites. A comprehensive experimental approach is employed, utilizing compact tension specimens of varying thicknesses, compositions, and crack length-to-width ratios to assess fracture toughness. Taguchi's optimization techniques, including the design of experiments with an L9 orthogonal array, analysis of variance (ANOVA), and regression analysis, are used to analyze the specified parameters. The three key factors and their respective levels considered in the study are reinforcement composition (3, 6, and 9 wt%), specimen thickness (10, 12, and 15 mm), and crack length-to-width ratio (0.45, 0.47, and 0.50). The experimental results indicate that increasing the composition of reinforcements beyond 6 wt% and certain crack length-to-width ratios decreases the fracture toughness of the hybrid composites. Through Taguchi's analysis, it is revealed that for a crack length-to-width ratio of 0.45, specimens with a thickness of 12 mm and 6 wt% reinforcements exhibit the highest fracture toughness. Further analysis underscores that the crack length-to-width ratio (a/W ratio) significantly affects fracture toughness (94%), followed by reinforcement composition and specimen thickness. The study provides valuable insights into optimizing the fracture toughness of aluminium–silicon carbide/alumina particulate composites. The identified optimized parameters 12 mm specimen thickness, 6 wt% reinforcement, and a 0.45 crack length-to-width ratio lead to enhanced fracture toughness. Additionally, finite element simulations support the experimental findings, with less than a 12% error, confirming the robustness of the optimized conditions. This research contributes to a deeper understanding of the interplay between process parameters and mechanical properties in particulate composite materials. © The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature 2025.