Nanoindentation for subminiaturized testing of irradiated materials FEM

Nanoindentation for sub-miniaturized testing of irradiated materials: FEM and experiments Khvan Tymofii SCK • CEN Mentor: Dmitry Terentyev SCK • CEN Co-mentor: Giovanni Bonny University of Liège Promoter: Ludovic Noels 1 © SCK CEN, 2018

Me Mol Belgian Nuclear Research Centre SCK • CEN Kharkiv V. N. Karazin Kharkiv National University 2 © SCK CEN, 2018

Nanoindentation and finite element modeling X. Xiao, D. Terentyev. Materials Science & Engineering A 743 (2019), 106 -113 A. Karimzadeh. Computational Material Science, 81 (2014), 595 -600 3 © SCK CEN, 2018

Modeling steps for microstructure Plastically deformed BCC Fe Pure BCC Fe Ferritic-martensitic steel Fe. Cr. C solid solution 4 © SCK CEN, 2018

Modeling steps for conditions Nanoindentation at room temperature Nanoindentation at elevated temperature Validation experiments are being performed in Université catholique de Louvain, Louvain-la-Neuve, Belgium Nanoindentation with effect of irradiation included Validation experiments will be performed in Research Centre Řež, Prague, Czech Republic 5 © SCK CEN, 2018

General application NI test data Constitutive laws from tensile test/reverse FEM NI FEM model Prediction Irradiated stress-strain curve Irradiation effect 6 © SCK CEN, 2018

Other useful applications of nanoindentation Strain softening after a dose of 1. 5 dpa Material can become brittle at room temperature after irradiation E. Gaganidze. Journal of Nuclear Materials 355 (2006) 83 -88 R. Chaouadi. Journal of Nuclear Materials 372 (2008) 379 -390 Damage peak Xue Bai. Metals 7, (2017), 25 A. Leitner. Nanomaterials 2018, 8(6), 366 7 © SCK CEN, 2018

Imperfection of indenter implementation A. Karimzadeh, Computational Materials Science 81 (2014) 595 -600 © SCK CEN, 2018

Pile-ups and sink-ins consideration M. Hardiman, Polymer testing 52 (2016) 157 -166 M. Hardiman. Polymer Testing 52 (2016) D. Mercier. Matériaux & Techniques 99 (2011), 169 -178 © SCK CEN, 2018

Size effect implementation Indentation size effect George Z. Voyiadjis, Polymer 55 (16) 5 2014, 4182 -4198 10 © SCK CEN, 2018

FEM code of Prof. Ludovic Noels Features: • Solver is based on discontinuous Galerkin method • Simulation geometry is described using Gmsh 3 D mesh generator • Open source, therefore allows user improvements • Free to use Application examples: Compact tension specimen Blast loaded cylinder Detonated pipe 11 Tensile test © SCK CEN, 2018

Small animated example 12 © SCK CEN, 2018

Short summary of performed work Experimental • Nanoindentation machine and testing process were studied as well as other important experimental setups (3 -point bending test bench, tensile deformation machine, Vickers hardness tester) • A set of nanoindentation tests were made for ion irradiated and non-irradiated, deformed and non-deformed steels and pure iron as a future reference data for model input and validation • FEM Just started… Some of the nanoindentation hardness curves were mathematically described by using A. Karrer’s* approach for irradiated nanoindentation hardness ΔHirr extrusion *A. Kareer, P. Hosemann. Journal of Nuclear Materials 498 (2018), 274 -281 13 © SCK CEN, 2018

Nanoindentation results 14 © SCK CEN, 2018

Irradiated hardness extrusion J 362 steel 9%Cr steel Specimen ID Dose, DPA h*, µm H 0 , GPa J 362 ~1 0, 05 2, 58 9%Cr ~1 0, 1 1, 94 D. Nix, H. Gao, J. Mech. Phys. Solids, Vol. 47, No. 3, 411 -425, 1998 15 © SCK CEN, 2018

Short summary of close future work (0. 5 – 1 year) Experimental FEM • A set of tests has to be done on differently oriented grains of pure iron sample, to see the dependence between grain orientation and an output • To get used into the FEM code we are going to use and understand how it works inside • Gradual filling of the experimental data list for unirradiated irons at room temperature for the first step model input • To decide which elastoplasticity model we are going to use to perform numerical simulations and how we should implement it in the code • To start the first numerical simulations to see and estimate which problems we can face in a future 16 © SCK CEN, 2018

Thank you for your attention! 17 © SCK CEN, 2018

Single grain crystal plasticity model Lattice friction effect Dislocation-dislocation interaction 18 Dislocation-grain boundary interaction (Hall-Petch effect) © SCK CEN, 2018