It had previously been shown that a phase transformation in UO2 was aided by the

presence of high-energy amorphous grain boundaries. Here, the role that the

structure of the grain boundary played in aiding that phase transformation was

studied. By examining three bicrystalline systems with differing types of grain

boundary (amorphous, Σ5 tilt and Σ5 twist), a study was made of the influence

upon the phase transformation behaviour of the critical applied stress required to

induce the phase transformation, of grain size and grain-boundary type. It was

found that there existed a critical applied stress below which the phase

transformation did not occur, and that the phase transformation occurred more

readily in systems with smaller grain sizes. A weak dependence, of the applied

stress required to cause the phase transformation, upon the grain-boundary energy

was observed.

The Role of Grain Boundary Structure in Stress-Induced Phase Transformation in

UO2. T.G.Desai, P.Nerikar, B.P.Uberuaga: Modelling and Simulation in Materials

Science and Engineering, 2009, 17[6], 064001