Effects of spatial energy distribution-induced porosity on mechanical properties of laser powder bed fusion 316L stainless steel
Effects of spatial energy distribution-induced porosity on mechanical properties of laser powder bed fusion 316L stainless steel
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DOI：
10.1016/j.addma.2021.101875
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发表时间：
2021-03-01
影响因子：
11
通讯作者：
Saldana, Christopher
中科院分区：
文献类型：
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作者：
Jost, Elliott W.;Miers, John C.;Saldana, Christopher
激光粉末床熔融（LPBF）增材制造（AM）相对于传统制造具有多种优势，但其在制造高性能部件方面的实用性目前受到LPBF过程中产生的内部缺陷（孔隙率）的阻碍，这些缺陷对整体机械性能产生了未知的影响。通过打印能量密度的变化诱导孔隙率分布，并使用计算机断层扫描检查所得拉伸样品，在75个样品中识别出近50，000个孔隙。从检测数据中定量提取孔隙率特征，并与力学性能进行比较，以了解孔隙率与整体拉伸性能之间关系的强度。确定了有用的孔隙率特性，用于预测部件性能。结果表明，延展性和应变在极限拉伸强度的全球拉伸性能最显着的孔隙率的影响，可以预测合理的准确性，使用简单的孔隙形状描述符，如体积，直径和表面积。此外，发现最大的孔对行为的影响最显著。具体地说，发现直径超过125 μ m的孔是性能估计的足够阈值。这些结果建立了对AM 316L不锈钢中复杂缺陷-性能关系的初步了解，并可用于制定认证标准，提高对更广泛工程合金的零件质量和可靠性的信心。
Laser powder bed fusion (LPBF) additive manufacturing (AM) offers a variety of advantages over traditional manufacturing, however its usefulness for manufacturing of high-performance components is currently hampered by internal defects (porosity) created during the LPBF process that have an unknown impact on global mechanical performance. By inducing porosity distributions through variations in print energy density and inspecting the resulting tensile samples using computed tomography, nearly 50,000 pores across 75 samples were identified. Porosity characteristics were quantitatively extracted from inspection data and compared with mechanical properties to understand the strength of relationships between porosity and global tensile performance. Useful porosity characteristics were identified for prediction of part performance. Results indicate that ductility and strain at ultimate tensile strength are the global tensile properties most significantly impacted by porosity and can be predicted with reasonable accuracy using simple porosity shape descriptors such as volume, diameter, and surface area. Moreover, it was found that the largest pores influenced behavior most significantly. Specifically, pores in excess of 125 mu m in diameter were found to be a sufficient threshold for property estimation. These results establish an initial understanding of the complex defect-performance relationship in AM 316L stainless steel and can be leveraged to develop certification standards and improve confidence in part quality and reliability for the broader set of engineering alloys.