Formation of nanocrystalline ?-ZrH in Zr-Nb alloy: Crystal structure and twinning

In the present work, the lattice parameter and the twins of gamma-ZrH hydride in Zr-2.5Nb-1Si were characterized using high resolution electron microscopy. The lattice parameters of gamma-ZrH (P42/mmc, Zr2H2 unit cell) is determined to be a = 0.336 nm, c = 0.508 nm. Twinning gamma-ZrH hydride ({011}<011> type) is for the first time reported in zirconium alloys, whose orientation relationship with alpha-Zr is [100]gamma-twins // [1210]alpha and (011)gamma-twins // (0002)alpha. The formation process of gamma-ZrH twins is also discussed based on a 'grow-in' mechanism during the transformation from alpha-Zr to gamma-ZrH hydride.

Automated summary

In this study, the lattice parameter and twins of gamma-ZrH hydride in Zr-2.5Nb-1Si were characterized using high resolution electron microscopy. The lattice parameters of gamma-ZrH were determined to be a = 0.336 nm, c = 0.508 nm. Twinning gamma-ZrH hydride ({011}<011> type) was reported for the first time in zirconium alloys, with an orientation relationship with alpha-Zr of [100]gamma-twins // [1210]alpha and (011)gamma-twins // (0002)alpha. The formation process of gamma-ZrH twins was also discussed based on a 'grow-in' mechanism during the transformation from alpha-Zr to gamma-ZrH hydride.