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<p>This study presents a systematic optimization of laser powder bed fusion (L-PBF) parameters for fabricating equiatomic CoCrFeMnNi high-entropy alloys (HEAs) with enhanced mechanical properties and reduced defect density. By varying the laser power, scanning speed, and hatch spacing under a constant layer thickness, a stable processing window —250 W laser power, 1400&#xa0;mm/s scanning speed, and 0.07&#xa0;mm hatch spacing—was identified. Specimens fabricated under these conditions exhibited an ultimate tensile strength of 579 ± 10&#xa0;MPa, a yield strength of 510 ± 13&#xa0;MPa, and a total elongation of 59 ± 3%. Electron backscatter diffraction (EBSD) analysis revealed a bimodal grain structure composed of coarse columnar grains and fine equiaxed grains, which contributed to both high strength and ductility. In-situ tensile testing combined with X-ray computed tomography (XCT) enabled real-time tracking of void nucleation and crack propagation, establishing a clear correlation between damage evolution and local stress states. The findings underscore the importance of precise control over energy input and scan strategy to minimize porosity and enhance structural integrity in L-PBF-processed HEAs. This work highlights the efficacy of process-parameter-driven strategies for tailoring microstructure and improving the mechanical reliability of HEAs in demanding structural applications.</p>

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Process Optimization of Laser Powder Bed Fusion for Equiatomic CoCrFeMnNi High-Entropy Alloy

  • 期刊论文

  • 发表日期：

    2026年1月14日

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  • Kun Lin,
  • Aiping Shen,
  • Chong Liu

摘要

This study presents a systematic optimization of laser powder bed fusion (L-PBF) parameters for fabricating equiatomic CoCrFeMnNi high-entropy alloys (HEAs) with enhanced mechanical properties and reduced defect density. By varying the laser power, scanning speed, and hatch spacing under a constant layer thickness, a stable processing window —250 W laser power, 1400 mm/s scanning speed, and 0.07 mm hatch spacing—was identified. Specimens fabricated under these conditions exhibited an ultimate tensile strength of 579 ± 10 MPa, a yield strength of 510 ± 13 MPa, and a total elongation of 59 ± 3%. Electron backscatter diffraction (EBSD) analysis revealed a bimodal grain structure composed of coarse columnar grains and fine equiaxed grains, which contributed to both high strength and ductility. In-situ tensile testing combined with X-ray computed tomography (XCT) enabled real-time tracking of void nucleation and crack propagation, establishing a clear correlation between damage evolution and local stress states. The findings underscore the importance of precise control over energy input and scan strategy to minimize porosity and enhance structural integrity in L-PBF-processed HEAs. This work highlights the efficacy of process-parameter-driven strategies for tailoring microstructure and improving the mechanical reliability of HEAs in demanding structural applications.