Functionally graded material of 304L stainless steel and inconel 625 fabricated by directed energy deposition: Characterization and thermodynamic modeling
Functionally graded material of 304L stainless steel and inconel 625 fabricated by directed energy deposition: Characterization and thermodynamic modeling
复制标题
DOI：
10.1016/j.actamat.2016.02.019
复制
发表时间：
2016-04-15
期刊：
影响因子：
9.4
通讯作者：
Beese, Allison M.
中科院分区：
文献类型：
--
作者：
Carroll, Beth E.;Otis, Richard A.;Beese, Allison M.
许多工程应用，特别是在极端环境中，需要具有随零件中位置而变化的特性的元件。功能梯度材料（FGM）具有硬度或密度等性能梯度，是满足这些要求的潜在解决方案。定向能量沉积（DED）的基于激光的增材制造工艺可用于通过根据位置调节递送到熔池的金属粉末的体积分数来制造具有成分梯度的金属部件。由于这是一种熔融工艺，在凝固过程中，第二相可能在梯度区中形成，这可能导致零件中出现不期望的性能。这项工作描述了实验和热力学研究的组成部分，从304L不锈钢逐步梯度Inconel 625。显微组织，化学，相组成，和显微硬度作为位置的函数，其特征在于通过显微镜，能量色散光谱，X射线衍射，和显微压痕。在梯度区的裂纹内发现少量的第二相颗粒。通过实验和热力学计算，确定了它们是由过渡金属碳化物组成。该研究提供了一种实验和热力学计算建模相结合的方法，用于制造和评估由DED增材制造制成的功能梯度材料。(C)2016 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Many engineering applications, particularly in extreme environments, require components with properties that vary with location in the part. Functionally graded materials (FGMs), which possess gradients in properties such as hardness or density, are a potential solution to address these requirements. The laser-based additive manufacturing process of directed energy deposition (DED) can be used to fabricate metallic parts with a gradient in composition by adjusting the volume fraction of metallic powders delivered to the melt pool as a function of position. As this is a fusion process, secondary phases may develop in the gradient zone during solidification that can result in undesirable properties in the part. This work describes experimental and thermodynamic studies of a component built from 304L stainless steel incrementally graded to Inconel 625. The microstructure, chemistry, phase composition, and microhardness as a function of position were characterized by microscopy, energy dispersive spectros-copy, X-ray diffraction, and microindentation. Particles of secondary phases were found in small amounts within cracks in the gradient zone. These were ascertained to consist of transition metal carbides by experimental results and thermodynamic calculations. The study provides a combined experimental and thermodynamic computational modeling approach toward the fabrication and evaluation of a functionally graded material made by DED additive manufacturing. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.