Evaluation of hydrogen embrittlement in ODS-Cu, Cu–Cr–Zr, and Cu–Cr alloys using slow strain rate technique test

Precipitation-hardened Cu–Cr–Zr alloy is proposed as a heat sink material for various components of the ITER owing to its high strength, high conductivity, and superior resistance against neutron irradiation. Oxide-dispersion-strengthened copper (ODS-Cu) was selected as the candidate material. Hydrogen embrittlement of Cu–Cr–Zr, Cu–Cr, and ODS-Cu (GlidCop® CuAl60) alloys was evaluated using the slow strain rate technique (SSRT) in 0.1 M sodium sulfate (Na₂SO₄) solutions under cathodic hydrogen charging or after D₂ gas exposure. Thermal desorption spectroscopy (TDS) measurements were performed to estimate the differences in the hydrogen-trapping sites using hydrogen charging methods. According to the TDS results, the quantity of hydrogen retained in ODS-Cu exceeded that in the other alloys by an order of magnitude because of hydrogen trapping at the grain boundaries and the particle/matrix interface. Cu–Cr–Zr alloys tend to trap more hydrogen than Cu–Cr alloys because of the addition of Zr. As a result of the SSRT, no hydrogen embrittlement was observed in any alloy, regardless of the hydrogen charging method. All alloys exhibited excellent hydrogen embrittlement resistance under the conditions adopted in this study.