Evaluation of fatigue properties under four-point bending and fatigue crack propagation in austenitic stainless steel with a bimodal harmonic structure

Austenitic stainless steel (JIS-SUS304L) with a bimodal harmonic structure, which is defined as a coarse-grained structure surrounded by a network of fine grains, was fabricated using powder metallurgy to improve both the strength and ductility. Four-point bending fatigue tests and K-decreasing test...

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Main Authors: Shoichi Kikuchi, Yuta Nakatsuka, Yoshikazu Nakai, Masashi Natakani, Mie Ota Kawabata, Kei Ameyama
Format: Article
Language:English
Published: Gruppo Italiano Frattura 2019-04-01
Series:Fracture and Structural Integrity
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Online Access:https://www.fracturae.com/index.php/fis/article/view/2256/2461
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author Shoichi Kikuchi
Yuta Nakatsuka
Yoshikazu Nakai
Masashi Natakani
Mie Ota Kawabata
Kei Ameyama
author_facet Shoichi Kikuchi
Yuta Nakatsuka
Yoshikazu Nakai
Masashi Natakani
Mie Ota Kawabata
Kei Ameyama
author_sort Shoichi Kikuchi
collection DOAJ
description Austenitic stainless steel (JIS-SUS304L) with a bimodal harmonic structure, which is defined as a coarse-grained structure surrounded by a network of fine grains, was fabricated using powder metallurgy to improve both the strength and ductility. Four-point bending fatigue tests and K-decreasing tests were conducted in air at room temperature under a stress ratio R of 0.1 to investigate fatigue crack propagation in SUS304L. The fatigue limit of this harmonic-structured material is higher than that of the material with a homogeneous coarse-grained structure. This is attributable to the formation of fine grains by mechanical milling and to the suppression of pore formation. In contrast, the threshold stress intensity range, ?Kth, for the harmonic-structured material is lower than that for the homogeneous coarse-grained material, while the crack growth rates, da/dN, are higher at comparable ?K. These results can be attributed to a reduction in the effective threshold stress intensity range, ?Keff,th, due to the presence of fine grains in the harmonic structure.
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institution Kabale University
issn 1971-8993
language English
publishDate 2019-04-01
publisher Gruppo Italiano Frattura
record_format Article
series Fracture and Structural Integrity
spelling doaj-art-20772fafa9ae4abca0935d7b24ef8c592025-01-03T00:39:31ZengGruppo Italiano FratturaFracture and Structural Integrity1971-89932019-04-01134854555310.3221/IGF-ESIS.48.5210.3221/IGF-ESIS.48.52Evaluation of fatigue properties under four-point bending and fatigue crack propagation in austenitic stainless steel with a bimodal harmonic structureShoichi KikuchiYuta NakatsukaYoshikazu NakaiMasashi NatakaniMie Ota KawabataKei AmeyamaAustenitic stainless steel (JIS-SUS304L) with a bimodal harmonic structure, which is defined as a coarse-grained structure surrounded by a network of fine grains, was fabricated using powder metallurgy to improve both the strength and ductility. Four-point bending fatigue tests and K-decreasing tests were conducted in air at room temperature under a stress ratio R of 0.1 to investigate fatigue crack propagation in SUS304L. The fatigue limit of this harmonic-structured material is higher than that of the material with a homogeneous coarse-grained structure. This is attributable to the formation of fine grains by mechanical milling and to the suppression of pore formation. In contrast, the threshold stress intensity range, ?Kth, for the harmonic-structured material is lower than that for the homogeneous coarse-grained material, while the crack growth rates, da/dN, are higher at comparable ?K. These results can be attributed to a reduction in the effective threshold stress intensity range, ?Keff,th, due to the presence of fine grains in the harmonic structure.https://www.fracturae.com/index.php/fis/article/view/2256/2461FatigueFracture mechanicsCrack closureGrain refinementPowder metallurgyStainless steel
spellingShingle Shoichi Kikuchi
Yuta Nakatsuka
Yoshikazu Nakai
Masashi Natakani
Mie Ota Kawabata
Kei Ameyama
Evaluation of fatigue properties under four-point bending and fatigue crack propagation in austenitic stainless steel with a bimodal harmonic structure
Fracture and Structural Integrity
Fatigue
Fracture mechanics
Crack closure
Grain refinement
Powder metallurgy
Stainless steel
title Evaluation of fatigue properties under four-point bending and fatigue crack propagation in austenitic stainless steel with a bimodal harmonic structure
title_full Evaluation of fatigue properties under four-point bending and fatigue crack propagation in austenitic stainless steel with a bimodal harmonic structure
title_fullStr Evaluation of fatigue properties under four-point bending and fatigue crack propagation in austenitic stainless steel with a bimodal harmonic structure
title_full_unstemmed Evaluation of fatigue properties under four-point bending and fatigue crack propagation in austenitic stainless steel with a bimodal harmonic structure
title_short Evaluation of fatigue properties under four-point bending and fatigue crack propagation in austenitic stainless steel with a bimodal harmonic structure
title_sort evaluation of fatigue properties under four point bending and fatigue crack propagation in austenitic stainless steel with a bimodal harmonic structure
topic Fatigue
Fracture mechanics
Crack closure
Grain refinement
Powder metallurgy
Stainless steel
url https://www.fracturae.com/index.php/fis/article/view/2256/2461
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