Role of interfaces in shock-induced plasticity in Cu/Nb nanolaminates

Abstract

We investigate deformation of pure Cu, pure Nb and 30 nm Cu/30 nm Nb nanolaminates induced by high strain rate shock loading. Abundant dislocation activities are observed in shocked pure Cu and Nb. In addition, a few deformation twins are found in the shocked pure Cu. In contrast, in shocked Cu/Nb nanolaminates, abundant deformation twins are found in the Cu layers, but only dislocations in the Nb layers. High resolution transmission electron microscopy reveals that the deformation twins in the Cu layers preferentially nucleate from the Cu(112)//Nb(112) interface habit planes rather than the predominant Cu(111)//Nb(110) interface planes. Our comparative study on the shock-induced plastic deformation of the pure metals (Cu and Nb) and the Cu/Nb nanolaminates underscores the critical role of heterogeneous phase interfaces in the dynamic deformation of multilayer materials.

Keywords:

• Cu/Nb nanolaminate
• shock loading
• interfaces
• deformation twinning

Acknowledgements

This work is sponsored by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Energy Frontier Research Center (EFRC) under Award No. 2008LANL1026. The authors thank Q.M. Wei, R. Hoagland and M.J. Zhuo for stimulating discussions and technical help.