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<p>Understanding the development of microstructure in layer-by-layer deposition technique is highly challenging, affecting the final mechanical properties of the component. The present study focuses on the deposition of Al-5%Si alloy using wire arc additive manufacturing (WAAM) to analyze the microstructure, mechanical properties, wear, and corrosion behavior across different regions of the build. Microstructure results show at the top region, grain growth is oriented toward the build direction, with reduced heat accumulation and a larger heat exposure area leading to fine grains and secondary-phase particles of various shapes and sizes. The middle region shows a combination of Al-Si and <i>α</i>-Al eutectic phases with columnar grain morphology, while the bottom region exhibits finer grains near the substrate due to a faster solidification rate, characterized by uniformly distributed lenticular grains. X-ray diffraction (XRD) analysis reveals <i>α</i>-Al and Mg<sub>2</sub>Si eutectic phases along grain boundaries. The ultimate tensile strength (UTS) of the as-deposited samples in 0°, 45°, and 90° orientations ranges between 145 ± 15&#xa0;MPa, with improved mechanical properties along the horizontal direction. Microhardness varies from 43 HV to 55&#xa0;HV along the build height, correlating with temperature fluctuations during deposition. Wear result shows the highest wear rate (4.8 × 10<sup>− 4</sup>&#xa0;mm<sup>3</sup>/m) in the middle region, attributed to coarse grain formation, while the top region demonstrates the lowest wear rate (4.2 × 10<sup>− 4</sup>&#xa0;mm<sup>3</sup>/m) due to higher microhardness and superior wear resistance. Scanning electron microscopy (SEM) of worn surfaces indicates delamination, severe adhesion, and abrasion as the primary wear mechanisms. Corrosion analysis using potentiodynamic polarization measurements reveals that corrosion resistance depends on microstructural inhomogeneity, with corrosion rates of 0.1822 ± 0.012&#xa0;mpy at the top, 0.1862 ± 0.032&#xa0;mpy at the middle, and 0.2221 ± 0.023&#xa0;mpy at the bottom region. Lower corrosion current density and higher corrosion potential in the top region confirm excellent corrosion resistance.</p>

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Microstructure, Mechanical, and Tribological Behavior of Al-5%Si Thin Wall Fabricated through Wire Arc Additive Manufacturing

  • 期刊论文

  • 发表日期：

    2025年2月13日

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  • Gaurav Kishor,
  • Krishna Kishore Mugada,
  • Raju Prasad Mahto

摘要

Understanding the development of microstructure in layer-by-layer deposition technique is highly challenging, affecting the final mechanical properties of the component. The present study focuses on the deposition of Al-5%Si alloy using wire arc additive manufacturing (WAAM) to analyze the microstructure, mechanical properties, wear, and corrosion behavior across different regions of the build. Microstructure results show at the top region, grain growth is oriented toward the build direction, with reduced heat accumulation and a larger heat exposure area leading to fine grains and secondary-phase particles of various shapes and sizes. The middle region shows a combination of Al-Si and α-Al eutectic phases with columnar grain morphology, while the bottom region exhibits finer grains near the substrate due to a faster solidification rate, characterized by uniformly distributed lenticular grains. X-ray diffraction (XRD) analysis reveals α-Al and Mg2Si eutectic phases along grain boundaries. The ultimate tensile strength (UTS) of the as-deposited samples in 0°, 45°, and 90° orientations ranges between 145 ± 15 MPa, with improved mechanical properties along the horizontal direction. Microhardness varies from 43 HV to 55 HV along the build height, correlating with temperature fluctuations during deposition. Wear result shows the highest wear rate (4.8 × 10− 4 mm3/m) in the middle region, attributed to coarse grain formation, while the top region demonstrates the lowest wear rate (4.2 × 10− 4 mm3/m) due to higher microhardness and superior wear resistance. Scanning electron microscopy (SEM) of worn surfaces indicates delamination, severe adhesion, and abrasion as the primary wear mechanisms. Corrosion analysis using potentiodynamic polarization measurements reveals that corrosion resistance depends on microstructural inhomogeneity, with corrosion rates of 0.1822 ± 0.012 mpy at the top, 0.1862 ± 0.032 mpy at the middle, and 0.2221 ± 0.023 mpy at the bottom region. Lower corrosion current density and higher corrosion potential in the top region confirm excellent corrosion resistance.