Effect of Dilute H on Phase Transformations near Hcp Zr Crack Tip

MARGARITA RUDA; GRACIELA BERTOLINO; DIANA FARKAS; PETER EVANS

San Diego, California, USA

Congreso; TMS 2011, 140th Annual Meeting & Exhibition; 2011

TMS

    We present atomistic studies of the deformation mechanisms occurringin the crack tip region during low temperature fracture of hcp Zr. Severalcompeting processes are involved, including the phase transformation to thebcc structure. Other major mechanisms which are responsible for ductilityare twinning and dislocation emission. For the cases in which a phasetransformation to bcc is observed, it results in a considerable improvement inductility. A dilute amount of H impurities placed at different distances fromthe crack tip significantly affects the competition between crack propagation,twin generation and phase transformations in the crack tip region. Inparticular, the presence of H can modify the size of the transformation regionand can lead to an increase in ductility.