PSI - Issue 60

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2023) 000 – 000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2023) 000 – 000

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 60 (2024) 433–443

© 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers Abstract Creep forming experiments were conducted on 1.6 mm thick sheets of 5024 alloy at an initial stress of 210 MPa in the temperature range 120 to 320°C for 2 hrs. The effect of forming temperature on the spring back behaviour and the mechanical properties of the material was studied. Results showed that spring back is high in the lower temperature range. Exposure to creep forming temperature had a marginal effect on the ultimate tensile strength and yield strength. At the same time, there was significant reduction in the ductility as a result of exposure to creep forming temperature in the range of 200-280°C. The fatigue strength of the alloy for 10 6 cycles was found to have increased from 250 to 290 MPa after exposure of the material to creep forming temperature of 200°C. Exposure to 300°C, however, did not exhibit a similar trend. Fractography studies on fatigue tested specimens showed delamination along the planes perpendicular to the fatigue crack propagation plane within the fatigue crack initiation zone. Analysis suggests that precipitation of β (Al 3 Mg 2 ) due to exposure to creep forming temperature regime appears to have been responsible for the observed change in the mechanical properties. Detailed analysis suggests the optimum creep forming temperature for 5024 alloy is 300°C for 2 hours, wherein the alloy shows the least spring back with desirable mechanical properties. © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers Keywords: Al-Mg-Sc alloy; creep forming; fatigue; fracture Abstract Creep forming experiments were conducted on 1.6 mm thick sheets of 5024 alloy at an initial stress of 210 MPa in the temperature range 120 to 320°C for 2 hrs. The effect of forming temperature on the spring back behaviour and the mechanical properties of the material was studied. Results showed that spring back is high in the lower temperature range. Exposure to creep forming temperature had a marginal effect on the ultimate tensile strength and yield strength. At the same time, there was significant reduction in the ductility as a result of exposure to creep forming temperature in the range of 200-280°C. The fatigue strength of the alloy for 10 6 cycles was found to have increased from 250 to 290 MPa after exposure of the material to creep forming temperature of 200°C. Exposure to 300°C, however, did not perpendicular to the fatigue crack propagation plane within the fatigue crack initiation zone. Analysis suggests that precipitation of β 3 2 ) due to exposure to creep forming temperature regime appears to have been responsible for the observed change in the mechanical properties. Detailed analysis suggests the optimum creep forming temperature for 5024 alloy is 300°C for 2 hours, wherein the alloy shows the least spring back with desirable mechanical properties. © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers Keywords: Al-Mg-Sc alloy; creep forming; fatigue; fracture Third International Conference on Structural Integrity 2023 (ICONS 2023) Influence of creep forming temperature on the mechanical properties and high cycle fatigue strength of Al-Mg-Sc-Zr alloy M. Suresh Kumar a *, N. Jagannathan b , Ramesh Bojja b , M. Sujata a , C.M. Manjunatha b a Materials Science Division, b Structural Integrity Division CSIR-National Aerospace Laboratories, Bangalore-560017 (INDIA) a a a Materials Science Division, b Structural Integrity Division CSIR-National Aerospace Laboratories, Bangalore-560017 (INDIA)

* Corresponding author: E-mail address: mskumar@nal.res.in * Corresponding author: E-mail address: mskumar@nal.res.in

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers 2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the ICONS 2023 Organizers 10.1016/j.prostr.2024.05.064