Percorrer por autor "Sharma, Priyaranjan"
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- Characterization and evaluation of joint properties of friction stir welded AA7075/GNPs joints obtained using square and cylindrical threaded toolsPublication . Fernandes, Filipe; Biradar, Rahul; Patil, Sachinkumar; Nagamadhu, M.; Sharma, PriyaranjanThis 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.
- Comparative investigation of friction stir welds reinforced with graphene nanoplatelets and copper in AA6082-T6 alloyPublication . Biradar, Rahul; Patil, Sachinkumar; Sharma, Priyaranjan; Fernandes, Filipe; Fernandes, FilipeFriction 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.
- Development and Mechanical Characterization of Ni-Cr Alloy Foam Using Ultrasonic-Assisted Electroplating Coating TechniquePublication . Pittala, Raj Kumar; Sharma, Priyaranjan; Anne, Gajanan; Patil, Sachinkumar; Varghese, Vinay; Das, Sudhansu Ranjan; Kumar, Ch Sateesh; Fernandes, FilipeMetal foams and alloy foams are a novel class of engineering materials and have numerous applications because of their properties such as high energy absorption, light weight and high compressive strength. In the present study, the methodology adopted to develop a Ni-Cr alloy foam is discussed. Polyurethane (PU) foam of 40PPI (parts per inch) pore density was used as the precursor and coating techniques such as electroless nickel plating (ELN), ultrasonic-assisted electroplating of nickel (UAEPN), and pack cementation or chromizing were used to develop the Ni-Cr alloy foam. The surface morphology, strut thickness and minimum weight gain after each coating stage were evaluated. It was observed from the results that the adopted coating techniques did not damage the original ligament cross-section of the PU precursor. The minimum weight gain and the coating thickness after the UAEPN process were observed to be 42 g and 40–60 m, respectively. The properties such as porosity percentage, permeability and compressive strength were evaluated. Finally, the pressure drop through the developed foam was estimated and verified to determine whether the developed foam can be used for filtering applications.
- Improvement in Corrosion Performance of ECAPed AZ80/91 Mg Alloys Using SS316 HVOF CoatingPublication . Naik, Gajanan M.; Sharma, Priyaranjan; Anne, Gajanan; Pittala, Raj Kumar; Kumar, Rahul; Satapathi, Gnane Swarnadh; Kumar, Ch Sateesh; Fernandes, FilipeMg AZ80/91 alloys are highly popular due to their lightweight, high strength-to-weight ratio, and good machinability. However, their moderate mechanical properties and corrosion resistance have limited their use in the automotive, aerospace, and defense sectors. This study primarily aims to enhance the mechanical performance and corrosion resistance of Mg AZ80/91 alloys, making them more suitable for applications in the aerospace and automotive industries. Firstly, equal-channel angular pressing (ECAP) of Mg AZ80/91 alloys has been attempted to improve their mechanical properties. Secondly, a high-velocity oxy-fuel (HVOF) coating of SS316 was applied over the Mg AZ80/91 substrate to enhance its corrosion resistance. In the second step, an HVOF coating of SS316 is applied over the Mg AZ80/91 substrate for better corrosion resistance. The experimental findings demonstrate that the application of an SS316 coating on the ECAP-4P AZ80/91 Mg alloy substrate results in a uniform and dense layer with an average thickness of approximately 80 5 m. The HVOF-based SS316 coating on 4P-ECAP leads to a noteworthy enhancement in microhardness and a reduction in the corrosion rate, especially in a NaCl solution (3.5 wt.%). This improvement holds great promise for producing reliable, long-lasting, and resilient automotive, aerospace, and defense components. The application of an HVOF-based SS316 coating onto the AZ80 Mg alloy, which had not undergone ECAP treatment, led to a substantial enhancement in corrosion resistance. This resulted in a notable decrease in the corrosion current density, reducing it from 0.297 mA/cm2 to 0.10 A/cm2.
- Machinability and surface integrity analysis of Ti-17 alloy using WEDC for advanced aero-engine applicationPublication . Fernandes, Filipe; Chinna, Ramatenki; Sharma, PriyaranjanRecent advancements in aerospace industry demand intricate aero-engine parts, leading to the increased use of titanium alloys, particularly Ti-17, due to its high strength, thermal stability, and corrosion resistance. However, its low thermal conductivity and tool wear tendency pose significant machining challenges, impacting surface integrity, fatigue life, and overall component performance. This study investigates the Wire Electrical Discharge Cutting (WEDC) process, revealing that the mechanism behind improved surface integrity lies in the controlled thermal input, which minimizes phase transformations and reduces residual stresses. Experimental results reveal that rough-cutting Ti-17 yields higher surface roughness of ∼2.68 μm than that of finish cutting of ∼1.01 μm, with increased microhardness up to 80 μm depth. Further, rough cutting leads to a thicker recast layer of ∼10–15 μm, and higher residual stresses of ∼540 MPa, while finish cutting achieves a thinner recast layer of ∼2–5 μm and reduced stresses of ∼304 MPa. The innovation of this study is the investigation of WEDC behavior in Ti-17 alloy, addressing a gap in understanding its surface integrity features to improve the performance, durability, and service life of aero-engine components, advancing next-generation aerospace manufacturing.