The major trap sites of deuterium in CuCrZr alloy

Abstract

The energy characteristics of the main deuterium (D) traps in CuCrZr alloy samples, which were previously annealed at temperatures of 773, 873, 973 and 1073 K and then exposed to D2 gas at a pressure of 2.5 × 104 Pa and a temperature of 723 K for 10 h, were studied by thermal desorption spectroscopy. Samples of oxygen free copper (OFC) were also investigated in the same way. For OFC, annealing at 773 K could reduce D retention appreciably. It indicates the temperature of 773 K is high enough to reduce the total D amount trapped by intrinsic defects (i.e. vacancies, dislocations and grain boundaries). However, for CuCrZr alloy, heat treatment does not reduce the D retention significantly until the annealing temperature is higher than 1073 K. Scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) observations show that the density of precipitate particles especially the Zr-rich precipitate particles increase for the 1073 K-annealed one. It suggests the dissolved Zr atoms in the substrate are responsible for the D retention in CuCrZr alloy. D detrapping energy from the dissolved Zr atoms in CuCrZr alloy is estimated to be 0.98 eV from the TDS measurements.

Keywords

• Heat treatment
• Hydrogen isotope
• Retention
• CuCrZr alloy