Ab initio and classical atomistic metallic-polymer interfaces and refractory metal grain boundaries
Title: Ab initio and classical atomistic metallic-polymer interfaces and refractory metal grain boundaries
SNIC Project: SNIC 2020/5-523
Project Type: SNIC Medium Compute
Principal Investigator: Pär Olsson <par.olsson@mau.se>
Affiliation: Malmö universitet
Duration: 2020-11-01 – 2021-11-01
Classification: 10304


The purpose of this project is to investigate (i) the strength of polymer interfaces and (ii) the impact of impurities on tungsten grain boundary strength. The former project is performed in collaboration with Tetra Pak. For (i) we will use quantum mechanical (DFT, using quantum espresso and VASP) and classical molecular dynamics (MD, using LAMMPS) modelling to invetigate the bond strength between acetic acids or polyethylene and aluminium oxide films. To this end we will utilize the newly established vdW-cx exchange-correlation functional (developed by Per Hyldgaard et al.) and the reaxFF forcefield for classical modelling. The DFT modelling will be used to investigate the adsorption of individual chains/acid groups onto the surface. We will use classical MD to investigate the adhesion between amorphous polymers and aluminium oxide substrate for different multiaxial deformation modes. The slow strain rate combined with utilization of numerically expensive all-atom reaxFF force fields require large paralellization on multiple (up to 128) cores for about one week per simulation on tetralith. We estimate the need of about 120 000 core-hours per month over a year for this effort at the tetralith system. For the grain boundary modelling of tungsten and Molybdenum we will use both DFT and classical atomistic modelling. Typically we intend to investigate how impurities affect the cohesive strength of grain boundaries. This effort requires the modelling of slip and brittle mechanisms for large supercells. To this end we will use the Kebnekaise system. A typical job would require up to about 112 cores. In total, we estimate the monthly use to 100 000 core hours per month on Kebnekaise. We expect that the group will expand with one new person in the group during early spring of 2021. Thus, we kindly ask for more resources this year.