Sumit Ghosh, Bernd M. Schönbauer, Sakari Pallaspuro, Mahesh Somani, Herwig Mayer, Jukka Kömi, Micro-mechanism associated with very high cycle fatigue crack initiation of advanced DQ&P processed steel, Procedia Structural Integrity, Volume 42, 2022, Pages 919-926, ISSN 2452-3216, https://doi.org/10.1016/j.prostr.2022.12.116
Micro-mechanism associated with very high cycle fatigue crack initiation of advanced DQ&P processed steel
|Author:||Ghosh, Sumit1; Schönbauer, Bernd M.1,2; Pallaspuro, Sakari1;|
1Materials and Mechanical Engineering, Centre for Advanced Steels Research, University of Oulu, Oulu 90014, Finland
2Department of Material Sciences and Process Engineering, Institute of Physics and Materials Science, University of Natural Resources and Life Sciences, Vienna (BOKU, Vienna 1190, Austria
|Online Access:||PDF Full Text (PDF, 1.9 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe202301162899
|Publish Date:|| 2023-01-16
In the present study, very high cycle fatigue (VHCF) characteristics and properties of a direct quenched and partitioned (DQ&P) medium carbon (0.4 wt.% C) steel having ultrahigh-strength (UTS > 2 GPa) was investigated using an ultrasonic-fatigue testing technique (∼19 kHz frequency) up to ∼10¹⁰ cycles at the load ratio (R) of −1 (fully reversed tension-compression). The occurrence of crack initiation in the VHCF regime was observed at interior non-metallic inclusions. The microstructural changes following VHCF failure underneath the fracture surfaces near the crack initiation sites were further investigated through transmission electron microscopy. Formation of a clear nanograined subsurface layer adjacent to the crack initiating site at the interior inclusion was noticeably evident. The variation of average grain size (60 − 140 nm) and thickness (300 − 1200 nm) of nanograined layers at different number of cycles to failure were measured in detail. Apparently, localized plastic deformation caused the fragmentation of martensitic laths and hence, the formation of aforesaid ultrafine-grained layers in the microstructures.
Procedia structural integrity
|Pages:||919 - 926|
23 European Conference on Fracture - ECF23
|Host publication editor:||
dos Reis, Luis Filipe Galrao
European Conference on Fracture
|Type of Publication:||
A4 Article in conference proceedings
|Field of Science:||
212 Civil and construction engineering
214 Mechanical engineering
216 Materials engineering
The authors are grateful for the financial support provided by the Jane and Aatos Erkko Foundation of Finland and Academy of Finland (grant No. #311934).
© The Author(s) 2022. Published by Elsevier B.V. This is an open access article under the CC-BY-NC-ND 4.0 license (http://creativecommons.org/licenses/by-nc-nd/4.0/).