Peridynamic simulations of the tetragonal to monoclinic phase transformation in zirconium dioxide

Abstract

Whether present as a manufactured stabilised ceramic, or as an oxide layer on zirconium alloys, mechanical degradation in zirconia is influenced by the tetragonal to monoclinic phase transformation.Peridynamic theory was implemented within the Abaqus finite element framework to understand how the tetragonal to monoclinic phase transformation can itself cause fracture in zirconia. In 2D these simulations represent a single grain, transforming via an isometric dilational expansion, surrounded by a homogenous monoclinic oxide. The effect of transformation time, applied bi-axial pressure, and the fracture strain were assessed using the change in strain energy and the amount of damage in the oxide surrounding the transformed grain. Reducing the applied compressive stress or applying a tensile stress reduces the transformation strain energy. The introduction of a fracture strain leads to damage in the surrounding oxide region largely in the form of cracks, and reduces the transformation strain energy further by reducing the constraint on the transforming grain. The extent of the fracture, and reduction in constraint on the transformed grain, is more significant with the application of a biaxial tensile pressure.

Modelling and experimental analysis of the effect of solute iron in thermally grown Zircaloy-4 oxides

“…This decreases the overall electrical potential gradient across the oxide, which should decrease the ingress of hydrogen into the metal [32,33]. An increased oxygen vacancy concentration could also affect the corrosion rate via its stabilizing effect on tetragonal ZrO 2 [34] as some studies [35][36][37] suggest that the tetragonal-to-monoclinic phase change induces the transition from low to high corrosion rates. If so, suppressing the phase change would extend times between transitions and hence reduce the overall corrosion rate.…”

Unraveling different influences of the fraction of the tetragonal phase in oxide films on the corrosion resistance of Zr alloys from the phase transition mechanism

“…They also studied the formation of micro-cracks in oxide films by using the FE method. 72 Now, from the calculated results of strains (Table 4) in phase transitions along different crystal orientations, we find that the strains in phase transition are anisotropy, and in some crystal directions, the lattice is compressed after the t-m transition, which induces tensile stress in these directions at the place that the t-m phase transition occurs. Therefore, here, we propose a new mechanism from atomic level simulation that how the t-m transition produces the tensile stress inducing the formation of micro-cracks.…”

“…Since the micro-cracks usually accompany the t-m transition, how the tensile stress produced by a phase transition with the total expansion of volume from the t to m phase attracts much attention. [69][70][71][72] Using the finite element (FE) method, Plat et al 69 demonstrated that shear tensile stress can be produced in such a transition by supposing that the expansion in the lattice volume from the t-m phase is microscopic isotropy. They also studied the formation of micro-cracks in oxide films by using the FE method.…”

Peri-Net: Analysis of Crack Patterns Using Deep Neural Networks

“…Peridynamics can be of particular use in understanding the damage in membranes and nanofiber [5], composites and brittle materials [6], brazed single-lap joints [7], fuel pellet [8], and biomembranes [9]. Peridynamics can be applied not only to damage studies, but also to technologically important areas such as prediction of viscoelastic materials [10], piezoresistive response of carbon nanotube nanocomposites [11], phase transformation in zirconium dioxide [12], shock and vibration [13], and indentation of thin copper film [14].…”