Formation of helium platelets in molybdenum

Microstructural evolution of irradiated tungsten: Ab initio parameterisation of an OKMC model

“…3 indicate also that the formation of He clusters without pre-existing damage is possible as was observed by Nicholson and Walls [80]. The most stable configuration for He atoms all in interstitial position is in a form of a platelet at least for clusters containing less than 10 He atoms at 0 K. The formation of He platelets was indeed observed in Mo by Evans [3] and in tungsten by Iwakiri et al [81]. For larger size clusters, platelets are also stable, however more work is necessary to determine the most stable configurations and in particular to find out when trap mutation (the emission of a SIA leaving a vacant site, i.e.…”

“…It can emit single entities, a vacancy, a SIA or a FIA, if the object contains this entity. Within this scheme, the emission of one or more than one SIA and vacancies from a pure FIA cluster which has been observed in Mo for instance [3] is not allowed. The object properties are: the types of objects (for example, a single vacancy v, a He atom, a di-vacancy, 2v, a single self-interstitial atom (SIA), etc.…”

Evolution of Helium Platelets and Associated Dislocation Loops inα-SiC

“…1). These are similar but more pronounced than in Si [11], B 4 C [12,13], Mo [14], Ti [15], and Ni [16]. The defects in the grain interior are separated by defect-free zones of about a 0.5 mm width from the boundaries.…”

Influence of dose rate on bubble formation by high energy He implantation in silicon

“…13 Helium platelets and planar groups of small helium bubbles have been first observed in molybdenum. 22 These platelets were lying in ͕110͖ planes. For an annealing temperature between 600 and 800°C, they were found to transform into a planar group of helium bubbles, but still lying on the ͕110͖ planes.…”