Classical molecular dynamics study of primary damage created by collision cascade in a ZrC matrix

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Classical molecular dynamics simulation of a high energy collision cascade initiated at 50 keV is used to study the primary damage state in a stoichiometric mono crystalline ZrC matrix. Analysis of the dynamics and the morphology of the displacement cascade reveals three distinct, well-defined time frames: collision phase, thermal spike and relaxation phase. On average, most of the atoms migrate over short distances, typically less than 11 Å, leading to numerous collision sequences in each sublattice. No amorphisation is observed, only a few point defects are created at the end of the collision cascades. All the Zr interstitials form a dumbbell structure oriented in the 〈1 1 1〉 direction and C interstitials are either isolated or form a 〈1 1 1〉 dumbbell structure. However, unlike metals, few antisites are created. Clusters of two interstitials of different species have a tendency to form small interstitial dislocation loops in the (1 1 1) plane.