Microstructure and mechanical properties of Inconel 686 fabricated by gas metal arc welding-based wire arc directed energy deposition: impact of cryogenic treatments

IF 3.5 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Materials Science Pub Date : 2024-10-15 DOI:10.1007/s10853-024-10295-2

S. Ajithkumar, B. Arulmurugan

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引用次数: 0

Abstract

In the present study, Inconel 686 thick-wall part manufactured utilizing gas metal arc welding-based wire arc directed energy deposition (WA-DED) was examined. The microstructure and mechanical properties of the fabricated Inconel 686 component across different sections, such as bottom, middle, and top, were explored, and the influence of cryogenic treatments, such as shallow and deep, on the properties of the fabricated specimens was examined. The optical and scanning electron microscopy revealed differences in microstructure across various regions of the deposited metal. The bottom region showed a columnar structure, the intermediate region displayed a combination of cellular structures, and the top layer featured an equiaxed structure. These variations contribute to heterogeneity and anisotropy in the mechanical characteristics. Moreover, the microstructure of the deep cryogenic treatment (DCT)-treated samples exhibited a finer grain structure in contrast to both the as-built and shallow cryogenic treatment (SCT)-treated WA-DED samples attributed to grain refinement. X-ray diffraction analysis observed that applying DCT decreased grain size, with the average grain size of the DCT-treated sample measuring 22.81 nm, while concurrently increasing the dislocation density to 19.22 × 10^–4 nm^–2. Energy-dispersive X-ray spectroscopy point analysis, elemental mapping, and line mapping were conducted to study the microsegregation and spatial distribution of alloying elements in the grain boundaries and interdendritic regions. Results indicated intensified segregation tendencies of alloying elements molybdenum (Mo) and tungsten (W) with increasing deposited height, peaking in the lowermost region. However, DCT samples exhibit reduced elemental segregation compared to as-built and SCT samples. The tensile strength and microhardness showed substantial differences across various areas. Cryogenic treatments considerably improved the mechanical properties of WA-DED specimens compared to their as-built state. As a result, the tensile strength improved by 7.23%, and the hardness strength increased by 8.98%.

Graphical abstract

查看原文本刊更多论文

通过基于气体金属弧焊的线弧定向能沉积制造的 Inconel 686 的微观结构和机械性能：低温处理的影响

本研究考察了利用基于气体金属弧焊的线弧定向能沉积（WA-DED）技术制造的 Inconel 686 厚壁部件。研究探讨了所制造的 Inconel 686 部件在底部、中部和顶部等不同部位的微观结构和机械性能，并考察了浅层和深层等低温处理对所制造试样性能的影响。光学和扫描电子显微镜显示了沉积金属不同区域的微观结构差异。底层区域显示出柱状结构，中间区域显示出蜂窝状结构的组合，而顶层则呈现出等轴状结构。这些变化导致了机械特性的异质性和各向异性。此外，与原样和浅低温处理（SCT）处理的 WA-DED 样品相比，深低温处理（DCT）处理的样品的微观结构显示出更细的晶粒结构，这归因于晶粒细化。X 射线衍射分析表明，应用 DCT 可减小晶粒尺寸，DCT 处理样品的平均晶粒尺寸为 22.81 nm，同时位错密度增至 19.22 × 10-4 nm-2。为了研究合金元素在晶界和树枝间区域的微偏析和空间分布，我们采用了能量色散 X 射线光谱点分析、元素图谱和线图谱。结果表明，合金元素钼（Mo）和钨（W）的偏析趋势随着沉积高度的增加而加剧，在最下部区域达到峰值。不过，与原样和 SCT 样品相比，DCT 样品的元素偏析有所减少。拉伸强度和显微硬度在不同区域显示出巨大差异。与原样相比，低温处理大大改善了 WA-DED 试样的机械性能。因此，抗拉强度提高了 7.23%，硬度提高了 8.98%。

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来源期刊

Journal of Materials Science 工程技术-材料科学：综合

CiteScore

7.90

自引率

4.40%

发文量

1297

审稿时长

2.4 months

期刊介绍： The Journal of Materials Science publishes reviews, full-length papers, and short Communications recording original research results on, or techniques for studying the relationship between structure, properties, and uses of materials. The subjects are seen from international and interdisciplinary perspectives covering areas including metals, ceramics, glasses, polymers, electrical materials, composite materials, fibers, nanostructured materials, nanocomposites, and biological and biomedical materials. The Journal of Materials Science is now firmly established as the leading source of primary communication for scientists investigating the structure and properties of all engineering materials.