PSI - Issue 25

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Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2019) 000 – 000 Structural Integrity Procedia 00 (2019) 000 – 000

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ScienceDirect

Procedia Structural Integrity 25 (2020) 438–444

© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers This paper aims at studying he cyclic pl stic behaviour of the 7075-T651 l minium alloy under fully-reversed strain-controlled conditions. Tests are conducted under strain-control mode, at room temperature, i a conventional servo-hydraulic machine, from smooth samples, using the single step method, with strain amplitudes (  /2) in the range ±0.5 to ±2.75%. This material has exh bited a mix d behaviour, i.e. cyclic strain-hardens a higher strain amplitudes (  /2/>1.1%) a d cyclic strain-softens at lower strain amp tudes (  /2<1.1%). A linear relationship between the degree of cyclic st ain-hardening and the train ampli ude has be n established for higher strain amplitudes. Fatigue-ductility and fatigue-strength properties agree with those found in the open literature for the same loading conditions. © 2020 The Authors. Published by Elsevier B.V. This is an ope acces article under C BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) This paper aims at studying the cyclic plastic behaviour of the 7075-T651 aluminium alloy under fully-reversed strain-controlled conditions. Tests are conducted under strain-control mode, at room temperature, in a conventional servo-hydraulic machine, from smooth samples, using the single step method, with strain amplitudes (  /2) in the range ±0.5 to ±2.75%. This material has exhibited a mixed behaviour, i.e. cyclic strain-hardens at higher strain amplitudes (  /2/>1.1%) and cyclic strain-softens at lower strain amplitudes (  /2<1.1%). A linear relationship between the degree of cyclic strain-hardening and the strain amplitude has been established for higher strain amplitudes. Fatigue-ductility and fatigue-strength properties agree with those found in the open literature for the same loading conditions. 1st Virtual Conference on Structural Integrity - VCSI1 Cyclic plastic behaviour of 7075 aluminium alloy F. Nogueira a *, J. Cunha a , A. Mateus a,b , C. Malça a,c , J.D. Costa d , R. Branco d a Centre for Rapid and Sustainable Product Development, Polytechnic Institute of Leiria, Portugal 1st Virtual Conference on Structural Integrity - VCSI1 Cyclic plastic behaviour of 7075 aluminium alloy F. Nogueira a *, J. Cunha a , A. Mateus a,b , C. Malça a,c , J.D. Costa d , R. Branco d a Centre for Rapid and Sustainable Product Development, Polytech ic Institute of Leiria, Portugal b Department of Mechanical Engineering, ESTG, Polytechnic Institute of Leiria, Portugal c Department of Mechanical Engineering, ISEC, Polytechnic Institutue of Coimbra, Portugal d CEMMPRE, Department of Mechanical Engineering, University of Coimbra, Portugal b Department of Mechanical Engineering, ESTG, Polytechnic Institute of Leiria, Portugal c Department of Mechanical Engineering, IS C, Polytechnic Institutue of Coimbra, Portugal d CEMMPRE, Department of Mechanical Engineering, University of Coimbra, Portugal Abstract Abstract

Peer-review under responsibility of the VCSI1 organizers

Keywords: Low-cycle fatigue; cyclic plastic behaviour, strain-softening, aluminium alloy; 7075-T651 Keywords: Low-cycle fatigue; cyclic plastic behaviour, strain-softening, aluminium alloy; 7075-T651

1. Introduction 1. Introduction

High-strength Al-Zn-Mg-Cu alloys are used in a vast number of structural applications, mainly due to their balance properties, in particular the excellent strength-to-weight ratio, attractive specific stiffness, good corrosion resistance, and high toughness [1]. Although structural applications are usually designed in such a way that materials High- tre gth Al-Zn-Mg-Cu a loys a used in a vast number of structural application , mainly due to their balance properties, in particular the excellent s rength-to-we ght ratio, attractive sp cific stiffness, good corrosion resistance, and high toughness [1]. Although structural applications are usually designed in such a way that materials

* Corresponding author. E-mail address: filipe.t.nogueira@ipleiria.pt * Corresponding author. E-mail address: filipe.t.nogueira@ipleiria.pt

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers 2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an ope access article under t e C BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers 10.1016/j.prostr.2020.04.049