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Microstructure evolution and local strengthening mechanisms in CoCrFeMnNi high entropy alloy joints reinforced with Inconel 625

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Resumo:In the fusion-based welding processes, filler materials are commonly used to adjust and improve the composition of the fusion zone with the aim of optimizing both microstructure and mechanical properties. However, in the field of welding high entropy alloys, the influence of different filler materials on the microstructure and mechanical response is still scarce, owing to the yet incipient usage of welding technologies for these novel, advanced engineering alloys. To bridge this knowledge gap, Inconel 625 filler wire was used during gas metal arc welding of the well-known CoCrFeMnNi high entropy alloy. To systematically analyze the microstructure evolution and mechanical properties of the welded joints, multiscale characterization techniques were employed. It is shown that the different regions of the welded joint possess distinct microstructural features due to the weld thermal cycle, which is further compounded in the fusion zone by the introduction of the filler material. The use of Inconel 625 filler promotes a solid solution strengthening effect in the fusion zone and became the main contributor to the yield strength of this region (302 MPa (via solid solution strengthening) vs 478 MPa (yield stress from tensile experiments). Since Hall-Petch strengthening is predominant in both base material and heat affected zone, but not on the fusion zone due to the large grain structure that developed, the addition of Inconel 625 filler demonstrates to be a feasible approach to increase the typically low fusion zone strength. By coupling microstructural characterization with mechanical property analysis, aided by the calculation of the strengthening mechanisms, we unveil processing, microstructure, property relationships, providing a broader basis for the widespread application of gas metal arc welding for high entropy alloys.
Autores principais:Shen, Jiajia
Outros Autores:Yang, Jin; Choi, Yeon Taek; Gonçalves, Rita; Pedro, Rodrigo; Santana, D. A.; Coury, F. G.; Schell, N.; Zeng, Zhi; Kim, Hyoung Seop; Oliveira, J. P.
Assunto:CoCrFeMnNi high entropy alloy Digital image correlation Gas metal arc welding Inconel 625 Mechanical testing Strengthening mechanisms Synchrotron X-ray diffraction Thermodynamic calculations General Materials Science Condensed Matter Physics Mechanics of Materials Mechanical Engineering
Ano:2025
País:Portugal
Tipo de documento:artigo
Tipo de acesso:acesso aberto
Instituição associada:Universidade Nova de Lisboa
Idioma:inglês
Origem:Repositório Institucional da UNL
Descrição
Resumo:In the fusion-based welding processes, filler materials are commonly used to adjust and improve the composition of the fusion zone with the aim of optimizing both microstructure and mechanical properties. However, in the field of welding high entropy alloys, the influence of different filler materials on the microstructure and mechanical response is still scarce, owing to the yet incipient usage of welding technologies for these novel, advanced engineering alloys. To bridge this knowledge gap, Inconel 625 filler wire was used during gas metal arc welding of the well-known CoCrFeMnNi high entropy alloy. To systematically analyze the microstructure evolution and mechanical properties of the welded joints, multiscale characterization techniques were employed. It is shown that the different regions of the welded joint possess distinct microstructural features due to the weld thermal cycle, which is further compounded in the fusion zone by the introduction of the filler material. The use of Inconel 625 filler promotes a solid solution strengthening effect in the fusion zone and became the main contributor to the yield strength of this region (302 MPa (via solid solution strengthening) vs 478 MPa (yield stress from tensile experiments). Since Hall-Petch strengthening is predominant in both base material and heat affected zone, but not on the fusion zone due to the large grain structure that developed, the addition of Inconel 625 filler demonstrates to be a feasible approach to increase the typically low fusion zone strength. By coupling microstructural characterization with mechanical property analysis, aided by the calculation of the strengthening mechanisms, we unveil processing, microstructure, property relationships, providing a broader basis for the widespread application of gas metal arc welding for high entropy alloys.