A Study of the Lattice Constant of ZrO2 during the Oxidation of Nanocrystalline Zircaloy-4

A nanocrystalline zircaloy-4 was corroded under 673 K/10.3 MPa, and the change of the lattice constant of ZrO2 during the phase transition was studied. The results show that the change of the lattice constant of ZrO2 formed on the nanocrystalline base is very different from that of lattice constant of ZrO2 formed on the coarse grain base. The unit cell volume of the tetragonal ZrO2 and monoclinic ZrO2 formed on the nanocrystalline base is constricted during the oxidation process. However, for the coarse grain base, the unit cell volume of the tetragonal ZrO2 is constricted, and the unit cell volume of the monoclinic ZrO2 is inflated. This phenomenon was discussed.