Hydrogenated vacancies lock dislocations in aluminium.
Due to its high diffusivity, hydrogen is often considered a weak inhibitor or even a promoter of dislocation movements in metals and alloys. By quantitative mechanical tests in an environmental transmission electron microscope, here we demonstrate that after exposing aluminium to hydrogen, mobile dislocations can lose mobility, with activating stress more than doubled. On degassing, the locked dislocations can be reactivated under cyclic loading to move in a stick-slip manner. However, relocking the dislocations thereafter requires a surprisingly long waiting time of ∼103s, much longer than that expected from hydrogen interstitial diffusion. Both the observed slow relocking and strong locking strength can be attributed to superabundant hydrogenated vacancies, verified by our atomistic calculations. Vacancies therefore could be a key plastic flow localization agent as well as damage agent in hydrogen environment.
Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
Degang
D
Xie
Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
Suzhi
S
Li
Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
Meng
M
Li
Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
Zhangjie
Z
Wang
Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.|Fraunhofer-Institut für Werkstoffmechanik IWM, 79108 Freiburg, Germany.
Peter
P
Gumbsch
Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
Jun
J
Sun
Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.|Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Evan
E
Ma
Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.|Department of Nuclear Science and Engineering and Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Ju
0000-0002-7841-8058
J
Li
Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) &Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
Zhiwei
Z
Shan