Scan strategy induced microstructure and consolidation variation in the Laser-Powder Bed Fusion (L-PBF) Additive Manufacturing of low alloy 20MnCr5 steel
Scan strategy induced microstructure and consolidation variation in the Laser-Powder Bed Fusion (L-PBF) Additive Manufacturing of low alloy 20MnCr5 steel
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DOI：
10.1016/j.matdes.2023.112160
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发表时间：
2023-07
期刊：
影响因子：
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通讯作者：
Xinliang Yang;G. Gibbons;D. Tanner;Zushu Li;P. Wilson;M. Williams;H. Kotadia
中科院分区：
文献类型：
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作者：
Xinliang Yang;G. Gibbons;D. Tanner;Zushu Li;P. Wilson;M. Williams;H. Kotadia
研究了扫描方式对激光-粉末床熔合（L-PBF）低合金20 MnCr 5钢显微组织演变、缺陷形成和宏观硬度性能的影响。关于扫描策略，采用先进的表征技术来研究（i）竣工微观结构，（ii）夹杂物尺寸和分布，以及（iii）孔隙度周围和构建内部的成分变化细节。微观组织表征表明，棋盘式扫描策略可以为力学性能的提高提供有利的微观组织。然而，与线性扫描策略样品相比，宏观硬度结果显示出较低的机械性能，这与改善的微观结构相矛盾。实验结果表明，棋盘式扫描策略促进了L-PBF中的氧化反应和SiO2的生成，由于激光重叠产生的过度热分布，导致了明显的缺陷形成。通过有限元分析和热力计算验证了这一点。只有在L-PBF过程中严格控制冶金质量，才能实现棋盘策略的组织改善优势。L-PBF工艺过程中的热分布优化和氧消除对于改善冶金质量和完工部件的上级机械性能至关重要。
The paper focuses on the effect of the scanning strategies on the microstructural evolution, defect formation, and macro-hardness performance of laser-powder bed fusion (L-PBF) produced samples of low alloy 20MnCr5 steel. Respect to the scanning strategies, advanced characterization techniques were employed to study (i) as-built microstructure, (ii) inclusion size and distribution, and (iii) details of compositional variation around porosity and within the build. Microstructural characterization shows that the chessboard scanning strategy can provide a favorable microstructure for the improvement of mechanical performance. However, macro-hardness results show a lower mechanical performance compared to the linear scanning strategy samples, which is contradicted by the improved microstructure. Experimental results reveal that the chessboard scanning strategy promotes the oxidation reaction andin-situoxide (SiO2) formation in L-PBF, which leads to significant defect formation due to the excessive thermal profile from the overlap of the laser. This has been validated through finite element analysis and thermodynamic computation. The advantages of microstructural improvement using the chessboard strategy can only be realized with strict control of the metallurgical quality during the L-PBF process. Thermal profile optimization and oxygen elimination during the L-PBF process could be critical for the improved metallurgical quality and superior mechanical performance of the as-built components.