NOMATEN's new scientific paper: Nanoindentation of single crystalline Mo: Atomistic defect nucleation and thermomechanical stability

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NOMATEN released new paper within the journal Materials Science and Engineering: A - "Nanoindentation of single crystalline Mo: Atomistic defect nucleation and thermomechanical stability". The authors team consist of Javier Dominguez PhD, Stefanos Papanikolaou PhD (Research Goup Leader - Materials informatics Structure and Function), Amin Esfandiarpour PhD, prof. Paweł Sobkowicz PhD DSc (Director for Scientific Operations) and prof. Mikko Alava PhD (NOMATEN CoE Director and Research Group Leader - Complexity in Materials).

The paper is available here: https://doi.org/10.1016/j.msea.2021.141912

Abstract: the mechanical responses of single crystalline Body-Centered Cubic (BCC) metals, such as molybdenum (Mo), outperform other metals at high temperatures, so much so that they are considered as excellent candidates for applications under extreme conditions, such as the divertor of fusion reactors. The excellent thermomechanical stability of molybdenum at high temperatures (400–1000 oC) has also been detected through nanoindentation, pointing towards connections to emergent local dislocation mechanisms related to defect nucleation. In this work, we carry out a computational study of the effects of high temperature on the mechanical deformation properties of single crystalline Mo under nanoindentation. Molecular dynamics (MD) simulations of spherical nanoindentation are performed at two indenter tip diameters and crystalline sample orientations, for the temperature range of 10–1000 K. We investigate how the increase of temperature influences the nanoindentation process, modifying dislocation densities, mechanisms, atomic displacements and also, hardness, in agreement with reported experimental measurements. Our results suggest that the characteristic formation and high-temperature stability of dislocation junctions in Mo during nanoindentation, in contrast to other BCC metals, may be the cause of the persistent thermomechanical stability of Mo.

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This project has received funding from the European Union Horizon 2020 research and innovation
programme under grant agreement No 857470 and from European Regional Development Fund
via Foundation for Polish Science International Research Agenda PLUS programme grant
No MAB PLUS/2018/8.
Poland
The project is co-financed from the state budget within the framework of the undertaking of the Minister of Science and Higher Education "Support for the activities of Centers of Excellence established under Horizon 2020".

Grant: 5 143 237,70 EUR
Total value: 29 971 365,00 EUR
Date of signing the funding agreement: December 2023

The purpose of the undertaking is to support entities of the higher education and science system that have received funding from the European Union budget in the competition H2020-WIDESPREAD-2018-2020/WIDESPREAD-01-2018-2019: Teaming Phase 2. in the preparation, implementation and updating of activities, maintenance of material resources necessary for carrying out activities, acquisition and modernization of scientific and research apparatus, maintenance and development of personnel potential necessary for the implementation of activities, and dissemination of the results of scientific activities.