Menon Nandana, Sawyer Brady A, Jamieson Cory D, Reutzel Edward W, Basak Amrita
Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
Applied Research Laboratory, The Pennsylvania State University, University Park, PA 16802, USA.
Materials (Basel). 2023 Jan 28;16(3):1129. doi: 10.3390/ma16031129.
The objective of this work is to compare the microstructure and microhardness properties of IN718 deposited by both powder- and wire-fed laser-directed energy deposition (L-DED) processes. The powder-fed L-DED is carried out on an Optomec LENS system while the wire-fed L-DED is performed in an in-house custom-built system. Several single-layer single-track specimens are fabricated using different combinations of process parameters to down-select the optimal process parameters for both systems. The finalized parameters are, thereafter, used to build thin-wall specimens having identical designs. The specimens are characterized using optical and electron microscopy as well as microhardness measurements. The results demonstrate that the powder-fed specimen, built using optimal process parameters, does not exhibit any distortion. On the contrary, the wire-fed specimen, built with optimal process parameters, show lesser porosity. Differences in elemental segregation are also detected in the two specimens. For example, nitrides and carbides are observed in the wire-fed specimen but not in the powder-fed specimen. The microhardness measurements reveal the powder-fed specimen has higher microhardness values compared to the wire-fed specimen. These results can be used to fabricate parts with sequential powder and wire deposition to achieve biomimetic structures of varying microstructure and microhardness properties.
这项工作的目的是比较通过粉末送料和丝材送料激光定向能量沉积（L-DED）工艺沉积的IN718的微观结构和显微硬度特性。粉末送料L-DED在Optomec LENS系统上进行，而丝材送料L-DED在内部定制系统中进行。使用不同的工艺参数组合制造了几个单层单道试样，以筛选出两个系统的最佳工艺参数。此后，使用最终确定的参数来制造具有相同设计的薄壁试样。使用光学显微镜和电子显微镜以及显微硬度测量对试样进行表征。结果表明，使用最佳工艺参数制造的粉末送料试样没有出现任何变形。相反，使用最佳工艺参数制造的丝材送料试样孔隙率较小。在两个试样中还检测到元素偏析的差异。例如，在丝材送料试样中观察到氮化物和碳化物，而在粉末送料试样中未观察到。显微硬度测量表明，与丝材送料试样相比，粉末送料试样具有更高的显微硬度值。这些结果可用于通过顺序进行粉末和丝材沉积来制造具有不同微观结构和显微硬度特性的仿生结构零件。
