The role of Ta on twinnability in nanocrystalline Cu–Ta alloys

ABSTRACT

Nanostructured Cu–Ta alloys show promise as high-strength materials in part due to their limited grain growth. In the present study, we elucidate the role of Ta on the transition from deformation twinning to dislocation-mediated slip mechanisms in nanocrystalline Cu through atomistic simulations and transmission electron microscopy characterization. In particular, computed generalized stacking fault energy curves show that as Ta content increases there is a shift from twinning to slip-dominated deformation mechanisms. Furthermore, heterogeneous twinnability from microstructural defects decreases with an increase in Ta. The computed effect of Ta on plasticity is consistent with the HRTEM observations.

GRAPHICAL ABSTRACT

IMPACT STATEMENT

We show for the first time using atomistic simulations and TEM that, similar to grain size, the Tanano-particles can be used to tailor the governing deformation mechanisms in NC-alloys.

KEYWORDS:

• Nanocrystalline
• twinning
• dislocation
• TEM

Acknowledgements

M. Rajagopalan and K.N. Solanki gratefully acknowledge the use of facilities within the LeRoy Eyring Center for Solid State Science at Arizona State University.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

This work was supported by U.S. Army Research Laboratory under contract W911NF-15-2-0038.