Mechanical behaviour near grain boundaries of He-implanted UO₂ ceramic polycrystals

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• 作者：M. Ibrahim^a ; ^b ; ^{marcelle.ibrahim@cea.fr} ; É ; . Castelier^a ; H. Palancher^a ; M. Bornert^b ; S. Caré ; ^b ; J.-S. Micha^c
• 关键词：Mechanical analysis ; Polycrystal ; Stress singularity ; Light ion implantation ; X-ray micro-diffraction ; 2D strain mapping
• 刊名：Journal of Nuclear Materials
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：483
• 期：Complete
• 页码：13-20
• 全文大小：1291 K
• 卷排序：483

文摘

For studying the micromechanical behaviour of UO2 and characterising the intergranular interaction, polycrystals are implanted with helium ions, inducing strains in a thin surface layer. Laue X-ray micro-diffraction is used to measure the strain field in this implanted layer with a spatial resolution of about 1 μm. It allows a 2D mapping of the strain field in a dozen of grains. These measurements show that the induced strain depends mainly on the crystal orientation, and can be evaluated by a semi-analytical mechanical model. A mechanical interaction of the neighbouring grains has also been evidenced near the grain boundaries, which has been well reproduced by a finite element model. This interaction is shown to increase with the implantation energy (i.e. the implantation depth): it can be neglected at low implantation energy (60 keV), but not at higher energy (500 keV).