1. Track formation in amorphous Fe$_{0.55}$Zr$_{0.45}$ alloys irradiated by MeV C$_{-60}$ ions: Influence of intrinsic stress on induced surface deformations
- Author
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C. Jaouen, A. Michel, Christophe Tromas, Jules Girard, Serge Della-Negra, Laboratoire de métallurgie physique (LMP), Université de Poitiers-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Nuclear and High Energy Physics ,Materials science ,business.industry ,Ion track ,02 engineering and technology ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,021001 nanoscience & nanotechnology ,01 natural sciences ,7. Clean energy ,Molecular physics ,Amorphous solid ,Stress (mechanics) ,Optics ,0103 physical sciences ,Stress relaxation ,Surface roughness ,Compression (geology) ,Deformation (engineering) ,010306 general physics ,0210 nano-technology ,business ,Instrumentation ,Hillock - Abstract
Amorphous Fe0.55Zr0.45 films, having thickness of 400 nm, were grown on silicon substrates by co-deposition using ion beam sputtering. Limited surface roughness makes this system particularly suitable for fine-scale scanning force microscopy analysis and nano-indentation. The samples were irradiated with MeV C60 clusters, and the surface morphology of single impacts was found to have a “doughnut” shape, i.e. hillocks having a central crater. Quantitative evaluation of the deformation was achieved by measuring their height and diameter. When C60 projectiles deviate from normal incidence, a tail emerges along the direction of the incident beam. The height of the hillock and length of the tail are increasing with the incidence angle, and the magnitude of the deformation indicates that the damage mainly occurs due to a radial coherent mass transport outwards from the track core by a compression shockwave-like mechanism. The residual compressive in-plane stress, ∼−0.4 GPa for the as-deposited films, was found to notably influence the C60 induced plastic deformations. Indeed, stress relaxation results in a marked decrease in height combined with a significant widening of the surface features. This “flat” surface morphology is attributed to an enhanced radial efficiency of the pressure pulse, owing to a significant reduction of the hardness of the amorphous film after stress relaxation. The overall picture outlined from our observations suggests that the surface damage induced by single MeV C60 ions possibly is the signature of plastic deformation induced at large distances by an energetic radial pressure pulse. This unsteady shockwave allows the energy transfer outwards from the localised region along the ion path that experiences a sudden transient heating.
- Published
- 2002
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