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Embrittlement of an elasto-plastic medium by an inclusion
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Cimbaro2019_Article_EmbrittlementOfAnElasto-plasti.pdf | Published version | 1.01 MB | Adobe PDF | View/Open |
Title: | Embrittlement of an elasto-plastic medium by an inclusion |
Authors: | Cimbaro, L Sutton, A Balint, D Paxton, A Hardy, M |
Item Type: | Journal Article |
Abstract: | A mathematical model for the embrittlement of a long elastic-plastic crack by a relatively small, misfitting inclusion is presented. The model makes direct contact with the Dugdale–Bilby–Cottrell–Swinden model as a limiting case. The particular case of an oxide inclusion with a triangular cross-section at the tip of an intergranular crack in the Ni-based superalloy RR1000 at 650∘C is considered. The positive misfit of the intrusion provides an additional tensile load on the crack tip and on the plastic zone, raising the local stress intensity factor kI and the crack tip opening displacement Δu above those when the inclusion is replaced by a dislocation-free zone of the same length. It is shown that for a given misfit strain and inclusion shape, the enhancement of kI and Δu is controlled by a dimensionless parameter ω=(σ/σ1)c/(2l)−−−−−√ where σ is the applied stress, σ1 is the yield stress, c is the crack length and l is the length of the inclusion. The anti-shielding effect of the intrusion is significant only when ω≲6. As a result of the anti-shielding effect of the intrusion, the stress singularity at the crack tip always exceeds the compressive normal stress that exists within the thickest part of the intrusion when it is isolated. It is also shown that the gradient of the hydrostatic stress within the intrusion subjected to different applied stresses drives the oxygen diffusion and, hence, assists the oxidation at the grain boundary. The fracture toughness is considerably greater than that of a bulk sample of the oxide particle, which we attribute to the plastic zone. |
Issue Date: | Mar-2019 |
Date of Acceptance: | 11-Jan-2019 |
URI: | http://hdl.handle.net/10044/1/67104 |
DOI: | https://doi.org/10.1007/s10704-019-00344-2 |
ISSN: | 0376-9429 |
Publisher: | Springer Verlag |
Start Page: | 87 |
End Page: | 100 |
Journal / Book Title: | International Journal of Fracture |
Volume: | 216 |
Issue: | 1 |
Copyright Statement: | © The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. |
Sponsor/Funder: | Engineering and Physical Sciences Research Council Rolls Royce Plc |
Funder's Grant Number: | EP/L015579/1 2200-00074140 |
Keywords: | Science & Technology Technology Materials Science, Multidisciplinary Mechanics Materials Science Fracture Inclusion Embrittlement Dugdale-Bilby-Cottrell-Swinden model Ni-based superalloys FATIGUE-CRACK-GROWTH FREE ZONE MODEL GRAIN-BOUNDARY OXIDATION HIGH-TEMPERATURE TIP OXIDATION CYCLE FATIGUE SUPERALLOY MECHANISM FRACTURE STRESS Mechanical Engineering & Transports 0905 Civil Engineering 0912 Materials Engineering 0913 Mechanical Engineering |
Publication Status: | Published |
Online Publication Date: | 2019-02-19 |
Appears in Collections: | Condensed Matter Theory Mechanical Engineering Physics Faculty of Natural Sciences Faculty of Engineering |