Browsing by Author "Nanjundaiah, R.S."

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    Fretting wear behavior on LPBF processed AlSi10Mg alloy for different heat treatment conditions
    (Elsevier Editora Ltda, 2024) Nanjundaiah, R.S.; Rao, S.S.; Praveenkumar, K.; Prabhu, T.R.; Shettigar, A.K.; Gowdru Chandrashekarappa, M.; Linul, E.
    To widen the industrial application of additively manufactured (AM) parts, the study of fretting wear behavior is essential, as it ensures the safety and reliability that drive innovation in design and materials. This study explores the fretting wear behavior of the as-built and heat-treated state of AlSi10Mg alloy fabricated, viz., laser powder bed fusion (LPBF). Initially, the as-built and T5, T6, and stress-relieved (SR) heat-treated samples were examined using scanning electron microscopy (SEM) to gain insights into the microstructural changes. The as-built samples exhibited a higher hardness level (135 HV) primarily due to the presence of very fine microstructure of the α-Al cellular matrix with embedded Si. The α-Al cellular structure dissolved with various heat treatments, and Si particles coarsened. The hardness decreased to 85, 79, and 67 HV for the T5, T6, and SR conditions, respectively. Subsequently, fretting tests were conducted on the samples, applying various normal loads of 10, 50, and 100 N. Further, the samples were characterized by the coefficient of friction (COF), worn surface morphology, and wear volume loss. The investigation showed that the as-built material showed less wear volume loss under all loading conditions than the heat-treated conditions. Furthermore, the T5 heat treated sample had a lower wear volume when compared to the T6 and SR heat-treated samples. The heat-treated sample exhibits compressive stress, whereas the LPBF processed, the as-built sample shows tensile stress. © 2024 The Authors
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    Investigating fretting wear behavior of LPBF processed AlSi10Mg alloy under variable frequency and heat treatment conditions
    (Elsevier B.V., 2025) Nanjundaiah, R.S.; Rao, S.S.; Praveenkumar, K.; Selvan, C.P.; Ram Prabhu, T.; Sahay, S.; Manivasagam, G.; Shettigar, A.K.; Gowdru Chandrashekarappa, G.C.
    This study examines the fretting wear behavior of AlSi10Mg alloy processed via Laser Powder Bed Fusion (LPBF) under different oscillation frequencies (5 Hz, 10 Hz, and 15 Hz) and heat treatment conditions (as-built, stress-relieved, T5, and T6) under a consistent load of 100 N. The fabricated and heat-treated samples were analyzed using X-ray diffraction, hardness testing, and residual stress measurements to evaluate dislocation density, hardenability, and the nature of residual stress. Fretting wear behavior was further assessed through evaluations of the coefficient of friction (COF), worn surface morphology, and wear volume loss using scanning electron microscopy (SEM) and 3D profilometry to understand the mechanism. Results indicated that the as-built samples exhibited superior resistance against fretting wear across all tested frequencies, a phenomenon attributed to their refined microstructure and higher dislocation density (FWHM: 0.213). The results show that lower frequencies primarily result in adhesive wear, with the oxide layer providing some protection, but higher frequencies accelerate abrasive and fatigue wear due to enhanced crack propagation and thermal softening. © 2025 The Authors