Alloying effect on grain-size dependent deformation twinning in nanocrystalline Cu–Zn alloys

Abstract

Grain-size dependency of deformation twinning has been previously reported in nanocrystalline face-centred-cubic metals, which results in an optimum grain-size range for twin formation. Here, we report, for the first time in experiments, the observed optimum grain sizes for deformation twins in nanocrystalline Cu–Zn alloys which slightly increase with increasing Zn content. This result agrees with the reported trend but is much weaker than predicted by stacking-fault-energy based models. Our results indicate that alloying changes the relationship between the stacking-fault and twin-fault energy and therefore affects the optimum grain size for deformation twinning. These observations should be also applicable to other alloy systems.

Keywords:

• deformation twinning
• nanomaterials
• alloys
• grain size
• stacking-fault energy

Acknowledgements

The authors acknowledge the use of Analytical Instrumentation Facility (AIF) at North Carolina State University, which is supported by the State of North Carolina and the National Science Foundation.

Additional information

Funding

This work was supported by the National Science Foundation of the USA [grant number DMR-1104667].