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<p>This study explores the various aspects of surface integrity and material deposition rate during electrical discharge coating (EDC) on 5754-grade aluminum alloy (AA) using powder metallurgical-based copper–tungsten (Cu–W) sintered green compact composite electrode. Trials were performed based on the full factorial design of experiments considering pulse-on time (T<sub>on</sub>) and discharge peak current (DC) as the process variables. Various aspects of surface integrity such as microhardness (MH), deposition layer thickness, microstructural phase transformation, surface roughness (Ra), and surface morphology of coating layer were investigated. The coating characteristics were examined using optical microhardness, scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Results indicate that increasing peak current (10–20 A) and pulse duration (100–200&#xa0;µs) generally leads to thicker coating layers with dense distributions. Minimal imperfections of coated surfaces are observed at DC = 10A and T<sub>on</sub> = 100&#xa0;µs values; however, at higher discharge peak currents (20 A) and extended pulse-on time (200&#xa0;µs), tool material deposition rates and surface roughness increase, with the formation of deeper and broader crater marks. Additionally, a greater percentage of elements are transferred and diffused onto the alloy surface with higher pulse-on time and discharge current levels. Microscopic observation and XRD analysis confirm the presence of a strong composite layer comprising W, WC, Cu, and Al, with EDS color mapping showing even element dispersion. Surface microhardness significantly increases during tool particle transfer, with the coated region displaying smaller indentation mark and a microhardness of 327 HV, nearly four times that of the AA5754 alloy. Furthermore, electric discharge coated specimens exhibit a significant reduction in wear with Ra value of 3.471&#xa0;µm compared to 5.557&#xa0;µm for uncoated counterparts (parent surface), leading to improved wear resistance.</p>

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Experimental investigation on surface modification of AA5754 alloy in electrical discharge coating using Cu–W composite electrode

  • 期刊论文

  • 发表日期：

    2025年9月2日

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  • Biswa Prakash Ghadei,
  • Debabrata Dhupal,
  • Santosh Kumar Sahu,
  • Pankaj Charan Jena,
  • Anshuman Das,
  • Sudhansu Ranjan Das

摘要

This study explores the various aspects of surface integrity and material deposition rate during electrical discharge coating (EDC) on 5754-grade aluminum alloy (AA) using powder metallurgical-based copper–tungsten (Cu–W) sintered green compact composite electrode. Trials were performed based on the full factorial design of experiments considering pulse-on time (Ton) and discharge peak current (DC) as the process variables. Various aspects of surface integrity such as microhardness (MH), deposition layer thickness, microstructural phase transformation, surface roughness (Ra), and surface morphology of coating layer were investigated. The coating characteristics were examined using optical microhardness, scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Results indicate that increasing peak current (10–20 A) and pulse duration (100–200 µs) generally leads to thicker coating layers with dense distributions. Minimal imperfections of coated surfaces are observed at DC = 10A and Ton = 100 µs values; however, at higher discharge peak currents (20 A) and extended pulse-on time (200 µs), tool material deposition rates and surface roughness increase, with the formation of deeper and broader crater marks. Additionally, a greater percentage of elements are transferred and diffused onto the alloy surface with higher pulse-on time and discharge current levels. Microscopic observation and XRD analysis confirm the presence of a strong composite layer comprising W, WC, Cu, and Al, with EDS color mapping showing even element dispersion. Surface microhardness significantly increases during tool particle transfer, with the coated region displaying smaller indentation mark and a microhardness of 327 HV, nearly four times that of the AA5754 alloy. Furthermore, electric discharge coated specimens exhibit a significant reduction in wear with Ra value of 3.471 µm compared to 5.557 µm for uncoated counterparts (parent surface), leading to improved wear resistance.