Molecular dynamics simulations are carried out for describing deposition and annealing processes of AlCoCrCuFeNi high entropy alloy (HEA) thin films. Deposition results in the growth of HEA clusters. Further annealing between 300K and 1500K leads to a coalescence phenomenon, as described by successive jump in the root mean square displacement of atoms. The simulated X-ray diffraction patterns during annealing reproduces the main feature of the experiments: a phase transition of the cluster structure from bcc to fcc .
A protection system for the JET ITER-like wall based on imaging diagnosticsa) Rev. Sci. Instrum. 83, 10D727 (2012); 10.1063/1.4738742Disentangling fluxes of energy and matter in plasma-surface interactions: Effect of process parametersThe knowledge of the effective energy deposited onto a surface by the reactive particles ͑ions, electrons, metastables, photons, etc.͒ in plasma processes such as thin-film deposition, sputtering, etching, etc., is of high interest to understand the basic mechanisms of energy transfer. In this article, a diagnostic is developed to directly measure the global energy transferred to surfaces ͑reactor walls, substrates, material to be modified, etc.͒ immerged in low-pressure plasmas. The diagnostic is based on a commercial HFM7-Vattel® microsensor, confined in a temperature-controlled substrate holder. The manufacturer calibration specifications are only given for atmospheric pressure. They cannot be used in low-pressure plasma conditions ͑typically 0.1-20 Pa͒. Thus, for this particular application, a calibration of the microsensor is required. It is performed at various pressures, between vacuum and the ambient, according to the NIST protocol and using a homemade blackbody ͑BB͒. It is shown that only curves obtained in vacuum or pressures below 0.1 Pa are valuable for a true calibration of the sensor. The others are perturbed by the heating of the gas in the BB surroundings. Measurements carried out in a typical transformer coupled plasma reactor in argon gas are presented. Typically the values are of the order of tens or hundreds of mW/ cm 2 in our experimental conditions. They are consistent with an estimation of the energy transferred by charged particles ͑ions and electrons͒ performed from Langmuir probe characterization of the plasma.
300 eV Helium implantation process into tungsten at 300 K has been studied with molecular dynamic simulations (MD). Predicted retention doses were compared to that obtained from experiments performed in equivalent conditions. A saturation phenomenon of the helium retention was evidenced for a number of impinging He atoms and a retention dose similar in both, experiments and simulations. From MD simulations it is learnt that observed Helium diffusion, formation and coalescence of clusters are the phenomena leading to the flaking of the substrate. These processes could explain the saturation of the Helium retention observed experimentally at low energies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.