High-throughput experimentation for microstructural design in additively manufactured 316L stainless steel
High-throughput experimentation for microstructural design in additively manufactured 316L stainless steel
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DOI：
10.1016/j.msea.2020.139841
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发表时间：
2020-08-19
期刊：
影响因子：
6.4
通讯作者：
Thoma, Dan
中科院分区：
文献类型：
--
作者：
Agrawal, Ankur Kumar;de Bellefon, Gabriel Meric;Thoma, Dan
在本研究中，高通量（HT）和低通量（LT）技术的组合被用来快速确定的加工窗口，并生成选择性激光熔化（SLM）的316 L不锈钢的加工地图。HT方法包括制造数百个六角螺母形状的样品，每个样品都用激光功率，扫描速度和舱口间距的独特组合进行处理。一个易于拆卸的支架允许从基板上快速提取样品，从而节省了加工成本和时间。硬度和浸渍密度测量用于HT表征，以确定最大强度和密度的加工窗口。在规定的处理窗口内，对样本进行了低通量（LT）显微结构检查。显微结构分析包括在各种长度尺度（即，晶粒尺寸和形态、织构、一次枝晶臂间距和熔池几何形状分析）。生成了作为体积能量密度函数的基于微结构的处理图。HT和LT方法的组合产生了硬度和一次枝晶臂间距之间的预测关系，使用Hall-Petch关系。提出了一个模型来解释熔池几何形状的微观结构的依赖性。HT方法可应用于SLM制造的其他合金部件的微观结构设计。
In the present study, a combination of high-throughput (HT) and low-throughput (LT) techniques was used to rapidly determine the processing window and generate processing maps for Selective Laser Melting (SLM) of 316L stainless steel. The HT method includes the fabrication of hundreds of hex nut-shaped specimens, each processed with a unique combination of laser power, scanning speed, and hatch spacing. An easily removable scaffolding permitted rapid sample extraction from the base plate, thus saving machining cost and time. Hardness and immersion density measurements were used for HT characterization to identify a processing window for maximum strength and density. Within the defined processing window, a low-throughput (LT) microstructural interrogation of specimens were performed. The microstructural analysis included quantification at various length scales (i.e., grains size and morphology, texture, primary dendrite arm spacing, and melt pool geometry analysis). Microstructure-based processing maps as a function of volumetric energy density were generated. The combination of HT and LT methods produced a predictive relationship between hardness and primary dendrite arm spacing using a Hall-Petch relationship. A model is proposed to explain the dependence of microstructure on the melt pool geometry. The HT method can be applied for the microstructural design of SLM-fabricated components in other alloys.