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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/10873
Title: A study on fatigue behavior of MIG-welded Al-Mg alloy with different filler-wire materials under mean stress
Authors: Gaur V.
Enoki M.
Okada T.
Yomogida S.
Published in: International Journal of Fatigue
Abstract: Cylindrical specimens of Ï•5 mm were cut from the weld bead of 50 mm thick MIG-welded Al-Mg alloy (Al-5083) plates with two different filler materials: Al-5183 (commonly used) and Al-5.8%Mg (special hardened new alloy). Load-controlled fatigue tests were done at different stress-ratios (R=-1,-0.5,0.1,0.5) using sinusoidal wave at 30 Hz and the performance of three popular finite-life empirical models: Gerber's parabola, Smith-Watson-Topper's model and Walker's model, was studied using the experimental data. Fatigue lives and endurance limits of both materials did not differ significantly, but they got reduced when the R-ratio was increased and the endurance limit followed the Gerber's parabola. A non-monotonic trend in the slope of S-N curves was observed: first increases and then decreases. Fracture surface observations revealed majority of surface-initiated failures at lower R-ratios (-1,-0.5), while for higher R-ratios (0.1,0.5), defect-induced failures were predominant. This shift in crack initiation site was attributed to the local cyclic plasticity due to stress-concentration and demonstrated using elastic-plastic finite element (FE) simulations. The detrimental effect of mean-stress on fatigue lives was attributed to combined effects of reduction in crack-nucleation time: due to stress concentration at defects and the crack closure effects. The three fatigue life models predicted monotonic decrease in slopes of S-N curves and thus did not give best results. A new model, based on Walker's model, was proposed which was able to capture the observed non-monotonic trend of the slopes of S-N curves and predicted fatigue lives better than these models. © 2017 Elsevier Ltd
Citation: International Journal of Fatigue (2018), 107(): 119-129
URI: https://doi.org/10.1016/j.ijfatigue.2017.11.001
http://repository.iitr.ac.in/handle/123456789/10873
Issue Date: 2018
Publisher: Elsevier Ltd
Keywords: Aluminum
Fatigue
Mean-stress
Porosity
Weld
ISSN: 1421123
Author Scopus IDs: 56229535200
7004847060
57210526304
57196470996
Author Affiliations: Gaur, V., Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
Enoki, M., Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
Okada, T., Research & Development Division, UACJ Corporation, 3-1-12 Chitose, Minato-ku, Nagoya-city, Aichi Pref. 455-8670, Japan
Yomogida, S., Research & Development Division, UACJ Corporation, 3-1-12 Chitose, Minato-ku, Nagoya-city, Aichi Pref. 455-8670, Japan
Funding Details: The authors are thankful to the Japanese research funding agency (JST) for funding this project through its Cross-ministerial Strategic Innovation Promotion (SIP), “Structural Materials for Innovation†program.
Corresponding Author: Gaur, V.; Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Japan; email: gaur.vidit@gmail.com
Appears in Collections:Journal Publications [ME]

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