Twin hopping in nanolayered Zr-2.5Nb

Abstract

Twinning in coarse-grained Zr is ubiquitous but not in nanostructured Zr due to the strong nano-confinement. Here we show that hexagonal close-packed (hcp) twins can proliferate in a nanolayered Zr-Nb as a result of the introduction of ductile body centered cubic (bcc) nanolayers. Both common {1 $\bar{{1}} $02} twins and less common { $\bar{1}\bar{1} $21} twins are found to propagate across the nanolayers by a novel twin hopping mechanism from one hcp layer to another. The fine ductile bcc nanolayers act as buffers that lower the back stress at the hcp/bcc interface far below that which usually constrains twinning.

Keywords

• twinning
• zr-2.5nb
• nanolayer
• interface
• plasticity