where Va-Zr, Vb-Zr, Vd-ZrD1.66, Vε-ZrD1.8 are the atom volumes in the phase structures of a-Zr, b-Zr, d-ZrD1.66 and ε-ZrD1.8, and a and c are
lattice constants. By substituting the lattice constants (a or/and c)
into the formula above, we get the atom volume strain after phase
transformations (see Table 2). It can be seen that the atom volumetric
strains of a/ε-ZrD1.8 and b/ε-ZrD1.8 are quite large,
reaching 17.98% and 10.24% respectively. This implies that there
exist large strains as a result of the transformation of the
deuterides.