Theoretical investigation of the 70.5° mixed dislocations in body-centered cubic transition metals

Lorenz Romaner, Tapaswani Pradhan, Anastasiia Kholtobina, Ralf Drautz, Matous Mrovec

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

Abstract

The low-temperature plasticity of body-centered cubic (bcc) metals is governed by [Formula presented] screw dislocations due to their compact, non-planar core. It has been proposed that 70.5 ° mixed (M111) dislocations may also exhibit special core structures and comparably large Peierls stresses, but the theoretical and experimental evidence is still incomplete. In this work, we present a detailed comparative study of the M111 dislocation in five bcc transition metals on the basis of atomistic simulations. We employ density functional theory and semi-empirical interatomic potentials to investigate both the core structure and the Peierls barrier of the M111 dislocation. Our calculations demonstrate that reliable prediction of M111 properties presents not only a very stringent test for the reliability of interatomic potentials but is also challenging for first-principles calculations for which careful convergence studies are required. Our study reveals that the Peierls barrier and stress vary significantly for different bcc transition metals. Sizable barriers are found for W and Mo while for Nb, Ta and Fe the barrier is comparably small. Our predictions are consistent with internal friction measurements and provide new insights into the plasticity of bcc metals.

OriginalspracheEnglisch
Aufsatznummer117154
Seitenumfang10
FachzeitschriftActa materialia
Jahrgang217.2021
Ausgabenummer15 September
Frühes Online-Datum13 Juli 2021
DOIs
PublikationsstatusVeröffentlicht - 15 Sept. 2021

Bibliographische Notiz

Funding Information:
This paper is dedicated to the memory of Prof. Gunther Schöck (1928-2015) who initiated our interest in the M111 dislocations. The authors gratefully acknowledge the financial support under the scope of the COMET program within the K2 Center Integrated Computational Material, Process and Product Engineering (IC-MPPE)(Project No 859480). This program is supported by the Austrian Federal Ministries for Climate Action, Environment, Energy, Mobility, Innovation and Technology (BMK) and for Digital and Economic Affairs (BMDW), represented by the Austrian research funding association (FFG), and the federal states of Styria, Upper Austria and Tyrol. TP would also like to acknowledge a scholarship from the International Max Planck Research School for Interface Controlled Materials for Energy Conversion.

Funding Information:
This paper is dedicated to the memory of Prof. Gunther Sch?ck (1928-2015) who initiated our interest in the M111 dislocations. The authors gratefully acknowledge the financial support under the scope of the COMET program within the K2 Center Integrated Computational Material, Process and Product Engineering (IC-MPPE)(Project No 859480). This program is supported by the Austrian Federal Ministries for Climate Action, Environment, Energy, Mobility, Innovation and Technology (BMK) and for Digital and Economic Affairs (BMDW), represented by the Austrian research funding association (FFG), and the federal states of Styria, Upper Austria and Tyrol. TP would also like to acknowledge a scholarship from the International Max Planck Research School for Interface Controlled Materials for Energy Conversion.

Publisher Copyright:
© 2021 Acta Materialia Inc.

Dieses zitieren