Structural transformation in two yttrium oxide powders irradiated with swift molybdenum ions

Abstract Swift molybdenum ions induce a structural transformation in Y 2 O 3 powders: the normal cubic phase is changed into the monoclinic phase. In this paper, it is shown that the initial crystallite size distribution in the grains has an influence on the efficiency of the phase transformation: the smaller the crystallites, the easier the cubic to monoclinic phase transformation. A mechanism is then proposed in order to explain the behaviour of two kinds of Y 2 O 3 powders differing by their crystallite size distribution.