Fatigue Crack Propagation in Shot Peened al 7475-t7351 Alloy Specimens

Ferreira, N.; Ferreira, J.A.M.; Antunes, P.V.; Costa, J.D.; C. Capela

Publication

Fatigue Crack Propagation in Shot Peened al 7475-t7351 Alloy Specimens

2016Journal article

dc.contributor.author	Ferreira, N.
dc.contributor.author	Ferreira, J.A.M.
dc.contributor.author	Antunes, P.V.
dc.contributor.author	Costa, J.D.
dc.contributor.author	C. Capela
dc.date.accessioned	2025-06-24T09:46:58Z
dc.date.available	2025-06-24T09:46:58Z
dc.date.issued	2016
dc.description.abstract	The approach to engineering design based on the flaws propagation assumption applying the principles of fracture mechanics is commonly used in aluminum structures for aerospace engineering, in which surface shot peening is an attractive method of improving fatigue performance, because it promotes the retardation of the crack initiation and earlier crack growth. The main purpose of present work was to analyze the effect of the surface shot peening on the fatigue crack propagation of the 7475 aluminum alloy with a T7351 heat treatment. Two types of fatigue tests were performed: constant amplitude and variable amplitude loading in which periodic overload blocks of 300 cycles are applied with intervals of Nint cycles. Surface micro shot peened promoted an increasing in micro-hardness only in order or 6% and created negative surface residual stresses in order of -174 MPa, which compare with the positive residual stresses of +291 MPa on the machined specimens. For tests at constant amplitude loading the effect of surface peening on da/dN-ΔK curves is quite limited, particularly for R = 0.4. However, this beneficial effect increases significantly near the threshold. Repeated overload block reduces significantly the fatigue crack propagation rate, being this effect particularly dependent of the intervals between the blocks. The maximum reduction of crack propagation rate and retardation effects were obtained for Nint = 7500 cycles.	eng
dc.description.sponsorship	The authors would like to acknowledge OGMA-Indústria Aeronáutica de Portugal, Alverca, Portugal, and also Dra Ana Guimarães and Eng. João Miranda for the collaboration in the supply of materials and samples used in this project and shot-peening processing. The authors thank also the sponsoring of this research by FEDER funds through the program COMPETE – Programa Operacional Factores de Competitividade – and by national funds through FCT – Fundação para a Ciência e a Tecnologia –, under the project UID/EMS/00285/2013.
dc.identifier.citation	N. Ferreira, J.A.M. Ferreira, P.V. Antunes, J.D. Costa, C. Capela, Fatigue Crack Propagation in Shot Peened al 7475-t7351 Alloy Specimens, Procedia Engineering, Volume 160, 2016, Pages 254-261, ISSN 1877-7058, https://doi.org/10.1016/j.proeng.2016.08.888
dc.identifier.doi	10.1016/j.proeng.2016.08.888
dc.identifier.issn	1877-7058
dc.identifier.uri	http://hdl.handle.net/10400.8/13394
dc.language.iso	eng
dc.peerreviewed	yes
dc.publisher	Elsevier BV
dc.relation	UID/EMS/00285/2013
dc.relation.hasversion	https://www.sciencedirect.com/science/article/pii/S1877705816331368
dc.relation.ispartof	Procedia Engineering
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject	Aluminum alloys
dc.subject	Crack propagation
dc.subject	Overloads
dc.subject	Micro shot peening
dc.title	Fatigue Crack Propagation in Shot Peened al 7475-t7351 Alloy Specimens	eng
dc.type	journal article
dspace.entity.type	Publication
oaire.citation.endPage	261
oaire.citation.startPage	254
oaire.citation.title	Procedia Engineering
oaire.citation.volume	160
oaire.version	http://purl.org/coar/version/c_970fb48d4fbd8a85
person.familyName	Capela
person.givenName	Carlos
person.identifier.ciencia-id	9B1E-6857-3D6B
person.identifier.orcid	0000-0003-3334-4945
person.identifier.rid	G-6395-2016
person.identifier.scopus-author-id	7801358401
relation.isAuthorOfPublication	9b079aa3-b79b-4395-b081-1f23d6a17514
relation.isAuthorOfPublication.latestForDiscovery	9b079aa3-b79b-4395-b081-1f23d6a17514