TY - JOUR
T1 - Three mechanisms of hydrogen-induced dislocation pinning in tungsten
AU - Li, Y.
AU - Morgan, T.W.
AU - Terentyev, Dmitry
AU - Favache, Audrey
AU - Wirtz, Marius
AU - Hoefnagels, J.P.M.
AU - van Dommelen, J.A.W.
AU - De Temmerman, Gregory
AU - Verbeken, Kim
AU - Geers, M.G.D.
N1 - Score=10
PY - 2020/7/15
Y1 - 2020/7/15
N2 - The high-flux deuterium plasma impinging a divertor degrades the long-term thermo-mechanical performance of its tungsten plasma-facing components. A prime actor in this is hydrogen embrittlement, a degradation mechanism that involves the interactions between hydrogen and dislocations, the primary carriers of plasticity. Measuring such nanoscale interactions is still very challenging, which limits our understanding. Here, we demonstrate an experimental approach that combines thermal desorption spectroscopy (TDS) and nanoindentation, allowing to investigate the effect of hydrogen on the dislocation mobility in tungsten. Dislocation mobility was found to be reduced after deuterium injection, which is manifested as a ‘pop-in’ in the indentation stress-strain curve, with an average activation stress for dislocation mobility that was more than doubled. All experimental results can be confidently explained, in conjunction with experimental and numerical literature findings, by the simultaneous activation of three mechanisms responsible for dislocation pinning:(i) hydrogen trapping at pre-existing dislocations, (ii) hydrogen-induced vacancies, and (iii) hydrogen-stabilized vacancies, contributing respectively 38%, 52%, and 34% to the extra activation stress. These mechanisms are considered to be essential for the proper understanding and modeling of hydrogen embrittlement in tungsten.
AB - The high-flux deuterium plasma impinging a divertor degrades the long-term thermo-mechanical performance of its tungsten plasma-facing components. A prime actor in this is hydrogen embrittlement, a degradation mechanism that involves the interactions between hydrogen and dislocations, the primary carriers of plasticity. Measuring such nanoscale interactions is still very challenging, which limits our understanding. Here, we demonstrate an experimental approach that combines thermal desorption spectroscopy (TDS) and nanoindentation, allowing to investigate the effect of hydrogen on the dislocation mobility in tungsten. Dislocation mobility was found to be reduced after deuterium injection, which is manifested as a ‘pop-in’ in the indentation stress-strain curve, with an average activation stress for dislocation mobility that was more than doubled. All experimental results can be confidently explained, in conjunction with experimental and numerical literature findings, by the simultaneous activation of three mechanisms responsible for dislocation pinning:(i) hydrogen trapping at pre-existing dislocations, (ii) hydrogen-induced vacancies, and (iii) hydrogen-stabilized vacancies, contributing respectively 38%, 52%, and 34% to the extra activation stress. These mechanisms are considered to be essential for the proper understanding and modeling of hydrogen embrittlement in tungsten.
KW - Hydrogen embrittlement
KW - Dislocation mobility
KW - Nanoindentation
KW - Crystal defects
KW - Thermal desorption spectroscopy
KW - TDS
UR - https://ecm.sckcen.be/OTCS/llisapi.dll/open/41682423
U2 - 10.1088/1741-4326/ab98a4
DO - 10.1088/1741-4326/ab98a4
M3 - Article
SN - 0029-5515
VL - 60
SP - 1
EP - 11
JO - Nuclear Fusion
JF - Nuclear Fusion
M1 - 086015
ER -