Deformation Twins in Nanocrystalline Body-Centered Cubic Mo as Predicted by Molecular Dynamics Simulations

Journal Article · Mon Oct 01 04:00:00 EDT 2012 · Acta Materialia

OSTI ID:1061016

Tonks, Michael; biner, Bulent; Zhang, Yongfeng; Millett, Paul C

This work studies deformation twins in nanocrystalline body-centered cubic Mo, including the nucleation and growth mechanisms as well as their effects on ductility, through molecular dynamics simulations. The deformation processes of nanocrystalline Mo are simulated using a columnar grain model with three different orientations. The deformation mechanisms identified, including dislocation slip, grain-boundary-mediated plasticity, deformation twins and martensitic transformation, are in agreement with previous studies. In (1 1 0) columnar grains, the deformation is dominated by twinning, which nucleates primarily from the grain boundaries by successive emission of twinning partials and thickens by jog nucleation in the grain interiors. Upon arrest by a grain boundary, the twin may either produce continuous plastic strain across the grain boundary by activating compatible twinning/slip systems or result in intergranular failure in the absence of compatible twinning/slip systems in the neighboring grain. Multiple twinning systems can be activated in the same grain, and the competition between them favors those capable of producing continuous deformation across the grain boundary.

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1061016
• Report Number(s): INL/JOU-12-26380
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 18 Vol. 60
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
grain boundaries
deformation twin
intergranular