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Percorrer por autor "Biradar, Rahul"

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  • Characterization and evaluation of joint properties of friction stir welded AA7075/GNPs joints obtained using square and cylindrical threaded tools
    Publication . Fernandes, Filipe; Biradar, Rahul; Patil, Sachinkumar; Nagamadhu, M.; Sharma, Priyaranjan
    This study investigates the joint properties and microstructural features of friction stir-welded (FSWed) AA7075 aluminum alloy composites reinforced with 1 wt % of graphene nanoplatelets (GNPs). It focuses on the influence of square (SQ) and cylindrical threaded (CT) tool pin geometries on material flow, GNPs dispersion, and weld quality. The authors conducted comprehensive evaluations using advanced characterization methods including scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and Raman spectroscopy. The results reveal formation of precipitates and well bonding between aluminum alloy and GNPs, resulting in better quality of welds. The SQ tool facilitated superior material stirring and uniform dispersion of GNPs, leading to the formation of fine, equiaxed grains in the nugget zone (NZ). Electron back scatter diffraction (EBSD) analysis presents reduction of grain size of base material from 38 μm to 10 μm in the NZ, significantly enhancing mechanical properties. Welds produced using the SQ tool exhibited higher microhardness (150 HV) and tensile strength (630 MPa) compared to those made with the CT tool (141 HV and 478 MPa), resulting in a 75 % improvement in joint efficiency. Fracture analysis revealed ductile failure in the heat-affected zone (HAZ), with fine dimples observed in SEM images. Additionally, the SQ tool weld demonstrated a lower wear rate, reduced from 70 μm to 25 μm, than its counterpart. These findings highlight the importance of tool geometry in producing defect-free, high-performance welds.
    2025-05Artigo de investigação Acesso aberto Ver mais
  • Comparative investigation of friction stir welds reinforced with graphene nanoplatelets and copper in AA6082-T6 alloy
    Publication . Biradar, Rahul; Patil, Sachinkumar; Sharma, Priyaranjan; Fernandes, Filipe; Fernandes, Filipe
    Friction stir welding (FSW)represents a solid-state welding method renowned for producing highquality joints, particularly in aluminum alloys. This study focuses on enhancing weld strength in the aerospace alloy AA6082-T6. The research involved conducting experiments to create FSW joints in AA6082-T6 by incorporating graphene nanoplatelets(GNPs) and copper as filler materials. Various characteristics of the joints, including microhardness, tensile strength, wear resistance, and corrosion behavior, were meticulously investigated. The experimental findings demonstrated that AA6082-T6 joints reinforced with GNPs exhibited significantly higher weld strength than conventional joints. This improvement can be attributed to the superior bonding and reinforcing effects of GNPs within the aluminum matrix. Furthermore, the GNPs incorporated joints displayed enhanced electrochemical and wear properties. This innovative approach in FSW presents a promising avenue for enhancing weld strength across diverse alloys through the integration of different reinforcement materials.
    2024Artigo científico Acesso aberto Ver mais