PSI - Issue 23

Available online at www.sciencedirect.com Available online at www.sciencedirect.com

ScienceDirect ScienceDirect

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

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

ScienceDirect

Procedia Structural Integrity 23 (2019) 457–462

© 2019 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 scientific committee of the ICMSMF organizers © 201 9 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 scientific committee of the IC MSMF organizers. region compared to the cryog nic temperatur case where deformation twins already are distributed in the microstruct re nd in thi ca will hinder the dislocations to move freely and instead cause stress field build up at the twin boundaries and subsequent microcrack and void formation . © 201 9 The Authors. Published by Elsevier B.V. This is an ope acces article under CC BY-NC-ND lic nse (http://creativecommon org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. 9th International Conference on Materials Structure and Micromechanics of Fracture TWIP and Fracture Behavior in the Superalloy 625 at Room and Cryogenic Temperatures Joakim Nordström a,b, * , Raveendra Siriki a , Mattias Calmunger b , Johan Moverare b and Guocai Chai a,b, a Sandvik Materials Technology, SE-811 81, Sandviken, Sweden b Division of Engineering Materials, Linköping University, SE -58183, Linköping, Sweden Abstract In this study an austenitic nickel base alloy (Alloy 625) with medium to high stacking fault energy was tensile tested at room temperature and at cryogenic temperature, - 196°C, to investigate if twinning was involved in the fracture process. Fracture surfaces and microstructure were characterized using scanning electron microscopy and texture was evaluated with scanning electron microscopy-electron backscatter diffraction at three positions along the tensile test specimens. Features where investigated with electron channelling contrast imaging. At room temperature the predominant deformation mechanism is slip and at cryogenic temperature slip is followed by deformation twinning. At room temperature deformation twinning will make an extra deformation contribution in the localized necking region compared to the cryogenic temperature case where deformation twins already are distributed in the microstructure and in this case will hinder the dislocations to move freely and instead cause stress field build up at the twin boundaries and subsequent microcrack and void formation . 9th International Conference on Materials Structure and Micromechanics of Fracture TWIP and Fracture Behavior in the Superalloy 625 at Room and Cryogenic Temperatures Joakim Nordström a,b, * , Raveendra Siriki a , Mattias Calmunger b , Johan Moverare b and Guocai Chai a,b, a Sandvik Materials Technology, SE-811 81, Sandviken, Sweden b Division of Engineering Materials, Linköping University, SE -58183, Linköping, Sweden Abstract In this study an a stenitic ni kel base alloy (Alloy 625) with medium to h gh stacking f ult energy was t nsile tested at room temperature and at cryogenic temperature, - 196°C, to inve ti ate if twinning was involved in the frac proc ss. Fracture surf ces and micr stru ture were cha acterized using scanning elec ron microscopy a d exture was evaluat d with scanning electron microscopy-electron b ckscatter diff c ion at three positions along th ensile test specimens. Features wh re i vestigated with electr n channelling contrast imaging. At room te perature the pred inant d formation echa ism is slip and at cryog nic tempe ature slip is followed by deformatio twin ing. At r om temp rature deformation winning will make an extra deforma io contribution in the local zed necking

Keywords: Deformation twinning; fracture; texture; Alloy 625; nickel base alloy; superalloy Keywords: Deformation twinning; fracture; texture; Alloy 625; nickel base alloy; superalloy

* Corresponding author. Tel.: +46-70-2613314 E-mail address: joakim.nordstrom@sandvik.com, guocai.chai@sandvik.ocm * Corresponding author. Tel.: +46-70-2613314 E-mail address: joakim.nordstrom@sandvik.com, guocai.chai@sandvik.ocm

2452-3216 © 2019 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 scientific committee of the IC MSMF organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an ope access article under t CC BY-NC-ND lic nse (http://creativecommon .org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers.

2452-3216 © 2019 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 scientific committee of the ICMSMF organizers 10.1016/j.prostr.2020.01.129