Characterization of carbides in nickel-base weld metals of 13 %Ni steel and first-principles study of their hydrogen solubility

IF 5.5 2区材料科学 Q1 MATERIALS SCIENCE, CHARACTERIZATION & TESTING

Materials Characterization Pub Date : 2025-10-08 DOI:10.1016/j.matchar.2025.115625

Chenjun Yu, Shohei Uranaka, Eita Tochigi, Taira Okita, Mitsuo Kimura, Tomoya Kawabata

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引用次数: 0

Abstract

The precipitation behavior and hydrogen-related properties of carbides in Ni-based weld metals fabricated by shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), and submerged arc welding (SAW) were systematically investigated. Microstructural characterization using SEM, EBSD, and TEM revealed that NbC is the dominant carbide in SMAW weld metals, while Mo₂C and M₆C prevail in GTAW and SAW weld metals, primarily located in inter-dendritic Nb- or Mo-rich segregation zones. Most carbide–matrix interfaces were found to be incoherent, and high dislocation densities were frequently observed around the precipitates, suggesting a potential for local hydrogen enrichment. First-principles calculations of hydrogen solution energies indicated that all carbide bulk phases exhibit significantly higher hydrogen solution energies than the Ni matrix, implying that they cannot act as effective hydrogen traps. However, non-coherent interfaces and surrounding dislocations may still serve as local hydrogen trapping sites. These findings provide critical insights into the precipitation characteristics and hydrogen–microstructure interactions in Ni-based alloy weld metals, which are relevant to the design and performance optimization of welded structures for hydrogen environment applications.

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13% Ni钢镍基焊缝金属中碳化物的表征及其氢溶解度的第一性原理研究

系统研究了保护金属电弧焊（SMAW）、钨极气体保护焊（GTAW）和埋弧焊（SAW）制备的ni基焊缝金属中碳化物的析出行为和氢相关性能。SEM、EBSD和TEM的显微组织表征表明，SMAW焊缝金属中以NbC为主，而GTAW和SAW焊缝金属中以Mo₂C和M₆C为主，主要分布在树枝晶间富Nb或Mo偏析区。大多数碳化物-基体界面不一致，析出相周围经常观察到高位错密度，表明可能存在局部富氢。氢溶蚀能第一性原理计算表明，所有碳化物体相的氢溶蚀能都明显高于Ni基体，这意味着它们不能作为有效的氢捕集器。然而，非相干界面和周围的位错仍然可以作为局部的氢捕获点。这些发现为ni基合金焊缝金属的析出特征和氢-微观结构相互作用提供了重要见解，这与氢环境下焊接结构的设计和性能优化有关。

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来源期刊

Materials Characterization 工程技术-材料科学：表征与测试

CiteScore

7.60

自引率

8.50%

发文量

746

审稿时长

36 days

期刊介绍： Materials Characterization features original articles and state-of-the-art reviews on theoretical and practical aspects of the structure and behaviour of materials. The Journal focuses on all characterization techniques, including all forms of microscopy (light, electron, acoustic, etc.,) and analysis (especially microanalysis and surface analytical techniques). Developments in both this wide range of techniques and their application to the quantification of the microstructure of materials are essential facets of the Journal. The Journal provides the Materials Scientist/Engineer with up-to-date information on many types of materials with an underlying theme of explaining the behavior of materials using novel approaches. Materials covered by the journal include: Metals & Alloys Ceramics Nanomaterials Biomedical materials Optical materials Composites Natural Materials.