Numéro |
J. Phys. IV France
Volume 12, Numéro 8, September 2002
|
|
---|---|---|
Page(s) | 249 - 261 | |
DOI | https://doi.org/10.1051/jp4:20020338 |
J. Phys. IV France 12 (2002) Pr8-249
DOI: 10.1051/jp4:20020338
Liquid metal embrittlement studies on model systems to the spallation target technology: The importance of nanometre-thick films
K. Wolski, V. Laporte, N. Marie and M. BiscondiCentre SMS, École des Mines de Saint-Etienne, 158 cours Fauriel, 42023 Saint-Etienne, France
Abstract
Liquid metal embrittlement (LME) is illustrated on the Cu-Bi and Cu-PbBi systems
at
300°C using either constant strain-rate tests at 10
-4 s
-1 or constant load tests at 25% of yield stress.
Intergranular penetration was studied in the Ni-Bi system at 700°C and was shown to result in
the
formation of slowly growing micrometre-thick and rapidly growing nanometre-thick films. Both
induce very strong intergranular brittleness but only micrometre-thick films are. visible by SEM
on
polished cross-sections. Nanometre-thick films were analysed by Auger electron spectroscopy
after
"in situ" fractures within the spectrometer; in particular, a series of analyses on an Ni bicrystal
proved the constant thickness of this film over several hundreds of microns. The severity of
embrittlement due to bismuth penetration was confirmed in the analysis of the Ni-PbBi system.
Based on these results, it is underlined that technological systems like T 91 steel / Pb or T91 /
PbBi
should work at temperatures below the wetting transition temperature (T
w), i.e. in the
temperature
range where intergranular films can't form. If it is not the case, nanometre-thick films should be
taken into account, both in the evaluation of the kinetics of embrittlement and in the modelling of
intergranular penetration and LME.
© EDP Sciences 2002