Formation mechanism of ⟨111⟩ interstitial dislocation loops from irradiation-induced C15 clusters in tungsten

In this paper, we report a formation mechanism of 1/2 < 111 > interstitial dislocation loops via the collapse of C15 clusters in bulk tungsten. The interstitial atoms formed C15 clusters in only a few picoseconds within a displacement cascade, and the transformation from C15 clusters to < 111 > interstitial loops was observed in both classical molecular dynamics and accelerated molecular dynamics simulations. This transformation was further confirmed under compressive stress, and it was determined to be accelerated once the < 111 > loops reacted with the C15 clusters. Three possible transformation processes were proposed, namely the C15 cluster directly transforming to < 111 > loops/clusters, a partial transformation to a < 111 > cluster with high mobility, thus leaving a shrunken C15 cluster behind, and a partially transformed < 111 > cluster but pinned by the adjacent shrunken C15 cluster. The formation mechanism provides an essential reference for predicting the evolution of microstructures in tungsten-based materials under irradiation.

Automated summary

This study reports a mechanism for the formation of 1/2 <111> interstitial dislocation loops through the collapse of C15 clusters in bulk tungsten. The transformation process is influenced by compressive stress and yields different results under different conditions. Three possible transformation processes have been proposed, providing important insights for predicting the evolution of microstructures in tungsten-based materials under irradiation.