Microstructure and Fracture Toughness of Fe–Nb Dissimilar Welded Joints

Qiaoling Chu; Lin Zhang; Tuo Xia; Peng Cheng; Jianming Zheng; Min Zhang; Jihong Li; Fuxue Yan; Cheng Yan

doi:10.3390/met11010086

Metals (Jan 2021)

Microstructure and Fracture Toughness of Fe–Nb Dissimilar Welded Joints

Qiaoling Chu,
Lin Zhang,
Tuo Xia,
Peng Cheng,
Jianming Zheng,
Min Zhang,
Jihong Li,
Fuxue Yan,
Cheng Yan

Affiliations

Qiaoling Chu: School of Materials and Engineering, Xi’an University of Technology, Xi’an 710048, China
Lin Zhang: School of Materials and Engineering, Xi’an University of Technology, Xi’an 710048, China
Tuo Xia: School of Materials and Engineering, Xi’an University of Technology, Xi’an 710048, China
Peng Cheng: CGN Advanced Materials Technology (Suzhou) Co., Ltd., Taicang 215400, China
Jianming Zheng: School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology, Xi’an 710048, China
Min Zhang: School of Materials and Engineering, Xi’an University of Technology, Xi’an 710048, China
Jihong Li: School of Materials and Engineering, Xi’an University of Technology, Xi’an 710048, China
Fuxue Yan: School of Materials and Engineering, Xi’an University of Technology, Xi’an 710048, China
Cheng Yan: School of Mechanical, Medical and Process Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia

DOI: https://doi.org/10.3390/met11010086
Journal volume & issue: Vol. 11, no. 1
p. 86

Abstract

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The relation between the microstructure and mechanical properties of the Fe–Nb dissimilar joint were investigated using nanoindentation. The weld metal consists mainly of Fe2Nb, α-Fe + Fe2Nb, Nb (s,s) and Fe7Nb6 phases. Radial cracks initiate from the corners of the impressions on the Fe2Nb phase (~20.5 GPa) when subjected to a peak load of 300 mN, whereas the fine lamellar structures (α-Fe + Fe2Nb) with an average hardness of 6.5 GPa are free from cracks. The calculated fracture toughness of the Fe2Nb intermetallics is 1.41 ± 0.53 MPam1/2. A simplified scenario of weld formation together with the thermal cycle is proposed to elaborate the way local phase determined the mechanical properties.

Published in Metals

ISSN: 2075-4701 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Mining engineering. Metallurgy
Website: http://www.mdpi.com/journal/metals

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