Fatigue Response of Additive-Manufactured 316L Stainless Steel

This study investigated the fatigue performance of 316L stainless steel fabricated via laser powder bed fusion (LPBF). Stress-controlled fatigue tests were performed at different stress amplitudes on vertically built samples using a frequency of 15 Hz and a stress ratio of 0.1. The stress amplitudes...

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Bibliographic Details
Published in:Metals (Basel ) 2024-09, Vol.14 (9), p.988
Main Authors: Chepkoech, Melody, Omoniyi, Peter, Owolabi, Gbadebo
Format: Article
Language:English
Subjects:
316L stainless steel
Amplitudes
Austenitic stainless steels
Crack initiation
Crack propagation
Crystal defects
Crystallography
Dimpling
Ductile fracture
Electron back scatter
Energy consumption
Failure modes
fatigue behavior
Fatigue failure
Fatigue strength
Fatigue tests
Fracture surfaces
Grain size
laser powder bed fusion
Manufacturing
Mechanical properties
Metal fatigue
Microscopy
Microstructure
Misalignment
Powder beds
Propagation modes
Residual stress
Stainless steel
Stress ratio
Striations
Tensile strength
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Summary:This study investigated the fatigue performance of 316L stainless steel fabricated via laser powder bed fusion (LPBF). Stress-controlled fatigue tests were performed at different stress amplitudes on vertically built samples using a frequency of 15 Hz and a stress ratio of 0.1. The stress amplitudes were varied to provide the cyclic response of the materials under a range of loading conditions. The average fatigue strength was determined to be 92.94 MPa, corresponding to a maximum stress of 185.87 MPa. The microstructures were observed through scanning electron microscopy (SEM) with the aid of electron backscattered diffraction (EBSD), and the average grain size of the as-built samples was determined to be 15.6 µm, with most grains having a preferred crystallographic orientation. A higher kernel average misorientation value was measured on the deformed surfaces, revealing the increased misorientation of the grains. Defects were observed on the fractured surfaces acting as crack initiators while deflecting the crack propagation paths. The fatigue failure mode for the LPBF 316L samples was ductile, as illustrated by the numerous dimples on fracture surfaces and fatigue striations.
ISSN:2075-4701
2075-4701
DOI:10.3390/met14090988