PSI - Issue 43

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000

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ScienceDirect

Procedia Structural Integrity 43 (2023) 3–8

© 2023 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 the responsibility of MSMF10 organizers. © 20 23 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 the responsibility of MSMF10 organizers. Abstract When the hcp metals are loade along the c axis, the a dislocations ar not activated and th plastic deformation is c rried by c+a dislocations or tw ing. The glide of c+a dislocatio s on different planes is anal sed for three representants f hcp metals: titanium, magnes um and zinc. The values of stacking fault energies alculated by densit functiona th ory are employed for the analysis of l ation behaviour. There is only one type of stable stacking faults on the pyrami al planes II, {2 -1 -1 2}, nd hence only the dissociation into two partials ½(c+a) = 1/6<-2 1 1 3> is considered. On the other hand, there are two types of stable stacking aults on the pyramidal planes I, {1 0 -1 1}, that must be aken into account. It i shown that in titanium the c+a dislocations prefer i l l but can cross-slip into the pyramidal planes II contrary to zinc where these dislocations remain to glide on the pyramidal planes II. © 20 23 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 the responsibility of MSMF10 organizers. 10th International Conference on Materials Structure and Micromechanics of Fracture Slip of c+a Dislocations in hcp Metals Václav Paidar * Institute of Physics, CAS, Na Slovance 2, 182 21 Praha, Czech Republic Abstract When the hcp metals are loaded along the c axis, the a dislocations are not activated and the plastic deformation is carried by c+a dislocations or twining. The glide of c+a dislocations on different planes is analysed for three representants of hcp metals: titanium, magnesium and zinc. The values of stacking fault energies calculated by density functional theory are employed for the analysis of dislocation behaviour. There is only one type of stable stacking faults on the pyramidal planes II, {2 -1 -1 2}, and hence only the dissociation into two partials ½(c+a) = 1/6<-2 1 1 3> is considered. On the other hand, there are two types of stable stacking faults on the pyramidal planes I, {1 0 -1 1}, that must be taken into account. It is shown that in titanium the c+a dislocations prefer to glide on the pyramidal planes I but can cross-slip into the pyramidal planes II contrary to zinc where these dislocations remain to glide on the pyramidal planes II. 10th International Conference on Materials Structure and Micromechanics of Fracture Slip of c+a Dislocations in hcp Metals Václav Paidar * Institute of Physics, CAS, Na Slovance 2, 182 21 Praha, Czech Republic 1. Introduction Plastic deformation of hexagonal metals is controlled by the dislocations with the shortest Burgers vectors 1/3<1 - 2 1 0> only for the loading directions different from the c-axis <0 0 0 1>. Otherwise, the c+a dislocations, with much larger (about twice longer) Burgers vectors 1/3<1 -2 1 3>, are activated or deformation twins can carry plastic strain. The ability to deform the crystals along the c axis is essential for higher ductility or fracture toughness of polycrystals. 1. Introduction Plastic deformati n of hexagonal metals is controlled by the dislocations with the shortest Burgers vectors 1/3<1 - 2 1 0> only for the l ading directions different from the c-axis <0 0 0 1>. Otherwise, the c+a dislocations, with much larger (about twice longer) Burgers vectors 1/3<1 -2 1 3>, are activated or deformation twins can carry plastic strain. The ability to deform the crystals along the c axis is essential for higher ductility or fracture toughness of polycrystals. Keywords: Hexagonal metals, properties of dislocations, glide on pyramidal planes Keywords: Hexagonal metals, properties of dislocations, glide on pyramidal planes

* Corresponding author. Tel.: +420 266052147. E-mail address: paidar@fzu.cz * Correspon ing author. Tel.: +420 266052147. E-mail address: paidar@fzu.cz

2452-3216 © 2023 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 the responsibility of MSMF10 organizers. 2452-3216 © 2023 The Authors. Published by Elsevier B.V. This is an ope access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under the responsibility of MSMF10 organizers.

2452-3216 © 2023 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 the responsibility of MSMF10 organizers. 10.1016/j.prostr.2022.12.226