Kink Band Formation in Graphite under Ion Irradiation at 100 and 298 K

The effects of displacing radiation in graphitic materials are important for technologies including nuclear power, graphitic-based nanocomposites and hybrid graphene–silicon high-speed integrated electronics. These applications expose graphitic materials to displacing irradiation either during manufacture and/or involve the deployment of these materials into irradiating environments. One of the most interesting phenomena in the response of graphite to irradiation is the formation of kink bands on the surface of the material. Here we apply the technique of transmission electron microscopy with in situ ion irradiation to observe the dynamic formation of these features. Kink bands were created at both 100 and 298 K with doming of the samples also observed due to radiation induced dimensional change leading to mechanical deformation. Probably at 298 K, but certainly at 100 K, there should be no point defect mobility in graphite according to the latest theoretical calculations. However, some of the theories of dimensional change in graphite require point defect motion and agglomeration in order to operate. The implications of the experimental results for existing theories and the possibility of thermal effects due to the ion irradiation are discussed.