3. Results and analysis
3.1. Influence of deuterium absorption temperature
The deuterium absorption amounts and the expansions in
thickness of Zircaloy-4 samples under the conditions of different
absorption temperatures are shown in Table 1 (second row). It can
be seen that the deuterium absorption amounts at 900 C, 800 C
and 700 C are determined to be 3.31%, 4.05% and 3.99% by weight,
and to be 3.18%, 3.60% and 3.66% by pressure. The deuterium absorption
amounts acquired by weight at each temperature are a
little more than those acquired by pressure. This is because the
samples absorbed more deuterium as they cooled down from the
deuterium absorption temperature to room temperature, as
mentioned in Section 2.2. The deuterium absorption amounts at
800 C and 700 C are nearly the same, but are much greater than
that at 900 C. The deuterium absorption amount at 900 C is only
about 85% of those at 800 C and 700 C. This may be due to the
thermodynamic stability of phase structure at different temperatures
[17,18]. As we know, the d phase (ZrD1.66) is more stable at
900 C, whereas the ε phase (ZrD1.8) is more stable at 800 C and
700 C. So there is higher deuterium absorption at 800 C and
700 C