Dislocation/hydrogen interaction mechanisms in hydrided nanocrystalline palladium films

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• 作者：Behnam Amin-Ahmadi^a ; Damien Conné ; table^b ; Marc Fivel^c ; Dö ; me Tanguy^d ; Renaud Delmelle^e ; Stuart Turner^a ; Loic Malet^f ; Stephane Godet^f ; Thomas Pardoen^e ; Joris Proost^e ; Dominique Schryvers^a ; Hosni Idrissi^a ; ^e ; ^{hosni.idrissi@uantwerpen.be" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Palladium ; Dislocation ; Hydrogen ; Ab-initio calculations ; Thin films
• 刊名：Acta Materialia
• 出版年：2016
• 出版时间：1 June 2016
• 年：2016
• 卷：111
• 期：Complete
• 页码：253-261
• 全文大小：2938 K

文摘

The nanoscale plasticity mechanisms activated during hydriding cycles in sputtered nanocrystalline Pd films have been investigated ex-situ using advanced transmission electron microscopy techniques. The internal stress developing within the films during hydriding has been monitored in-situ. Results showed that in Pd films hydrided to β-phase, local plasticity was mainly controlled by dislocation activity in spite of the small grain size. Changes of the grain size distribution and the crystallographic texture have not been observed. In contrast, significant microstructural changes were not observed in Pd films hydrided to α-phase. Moreover, the effect of hydrogen loading on the nature and density of dislocations has been investigated using aberration-corrected TEM. Surprisingly, a high density of shear type stacking faults has been observed after dehydriding, indicating a significant effect of hydrogen on the nucleation energy barriers of Shockley partial dislocations. Ab-initio calculations of the effect of hydrogen on the intrinsic stable and unstable stacking fault energies of palladium confirm the experimental observations.