NOMATEN JUNIOR SEMINAR: Dislocations and nanomechanics in alumina using atomistic simulations

Date
Date 2
NOMATEN JUNIOR SEMINAR
 
Tuesday, April 26 2022 13:00 (1.00PM CET)
 
https://www.gotomeet.me/NCBJmeetings/junior-nomaten-seminar
  
 
Dislocations and nanomechanics in alumina using atomistic simulations
 
 
Qinqin Xu PhD, NOMATEN CoE, NCBJ
 


Abstract:
The study of nano-objects is of particular interest due to their outstanding mechanical properties. While metal nanocrystals are generally characterized by high yield strength and ductility under extreme compressive stress, very few is known about other classes of materials including ceramic or semi-conductors. Recently, it was shown that ceramic nano-particles such as aluminum or magnesium oxides could plastically deform under high stress without cracking what might have significant implications for the sintering and compaction of nanocrystalline ceramics. However, only few evidences of the elementary deformation processes were addressed so far, especially in the case of α-Al2O3 nanocrystals.

In this study, we propose to investigate α-Al2O3 nanoparticle mechanics using molecular dynamics simulations. Firstly, several α-Al2O3 bulk properties as lattice and elastic constants, stacking-fault and surface energies as well as basal edge dislocation features as compared to existing experimental/numerical literature are investigated to test the transferability of various interatomic force fields to the nanomechanical field. Among all the tested parameterizations, the 2/3-body Vashishta interatomic potential has shown to be particularly adapted to the overall study. Secondly, nanoparticle compression tests are modeled as function of orientation and temperature including a detailed analysis of dislocation-based mechanisms for several sizes of α-Al2O3 nanoparticles. Results are discussed in the context of recent nanomechanics experiments as well as pioneer works performed on bulk alumina.

Bio:
Qinqin Xu had earnd his Doctor degree at the MATEIS lab, INSA de Lyon, France. His project was funded by the Chinese Scholarship Council (CSC). Recently he is emlpoyed as assistant professor at NOMATEN Centre of Excellence at the National Centre for Nuclear Research, Poland.
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JUNIOR NOMATEN Seminar

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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.