A molecular dynamics study on the influence of defects on tungsten material properties
(2022) In ISRN LUTFD2/TFME-22/5044-SE(1-80) FMEM01 20212Mechanics
- Abstract
- This masters thesis work has been carried out at the divisions of mechanics at Lund university. The purpose has been to find out more about tungsten and how its material properties are affected by crystal structure defects. This is of interest as tungsten at the research facility ESS will be used in an environment that leads to defects in the material.
Molecular Dynamics (MD), which is a simulation method, will be used in this work for simulating tungsten with different defects. The reason to why these simulations will be performed is that it will increase the understanding of the mechanical behaviour of tungsten.
The simulations starts with observing which influence varied variables of sample size, temperature, crystal orientation,... (More) - This masters thesis work has been carried out at the divisions of mechanics at Lund university. The purpose has been to find out more about tungsten and how its material properties are affected by crystal structure defects. This is of interest as tungsten at the research facility ESS will be used in an environment that leads to defects in the material.
Molecular Dynamics (MD), which is a simulation method, will be used in this work for simulating tungsten with different defects. The reason to why these simulations will be performed is that it will increase the understanding of the mechanical behaviour of tungsten.
The simulations starts with observing which influence varied variables of sample size, temperature, crystal orientation, potential function, strain rate and boundary condition have on the material properties. This is done in order to choose suitable data input for the final simulations which explores the effect defects like vacancies, vacancy clusters and helium atoms can have on the material properties of tungsten.
From the simulations it emerges that vacancies in a tungsten sample will not affect Young's modulus, but the peak stress and the strain at peak stress will decrease a bit. For this defect the position of the vacancy matters. If this is positioned on a surface, this is worse for the mechanical properties, compared to if it is inside the sample.
Neither vacancy clusters will contribute to a change in Young's modulus. The larger the vacancy cluster, the larger the decrease in the strain at peak stress. The peak stress will not differ this much.
Regarding helium blisters, no risk exists for formation of such on the surface at these temperatures.
Smaller helium clusters inside tungsten can be formed in the environment at ESS, the deterioration of mechanical properties can be quite large due to this.
The risk of larger helium cluster forming in tungsten are small at these temperatures. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9079628
- author
- Fredriksson, Allan LU
- supervisor
-
- Per Hansson LU
- Leon Petersson LU
- organization
- course
- FMEM01 20212
- year
- 2022
- type
- H3 - Professional qualifications (4 Years - )
- subject
- keywords
- Molecular dynamics
- publication/series
- ISRN LUTFD2/TFME-22/5044-SE(1-80)
- report number
- TFME-5044
- other publication id
- ISRN
- language
- English
- id
- 9079628
- date added to LUP
- 2022-11-02 08:39:34
- date last changed
- 2022-11-02 08:39:34
@misc{9079628,
abstract = {{This masters thesis work has been carried out at the divisions of mechanics at Lund university. The purpose has been to find out more about tungsten and how its material properties are affected by crystal structure defects. This is of interest as tungsten at the research facility ESS will be used in an environment that leads to defects in the material.
Molecular Dynamics (MD), which is a simulation method, will be used in this work for simulating tungsten with different defects. The reason to why these simulations will be performed is that it will increase the understanding of the mechanical behaviour of tungsten.
The simulations starts with observing which influence varied variables of sample size, temperature, crystal orientation, potential function, strain rate and boundary condition have on the material properties. This is done in order to choose suitable data input for the final simulations which explores the effect defects like vacancies, vacancy clusters and helium atoms can have on the material properties of tungsten.
From the simulations it emerges that vacancies in a tungsten sample will not affect Young's modulus, but the peak stress and the strain at peak stress will decrease a bit. For this defect the position of the vacancy matters. If this is positioned on a surface, this is worse for the mechanical properties, compared to if it is inside the sample.
Neither vacancy clusters will contribute to a change in Young's modulus. The larger the vacancy cluster, the larger the decrease in the strain at peak stress. The peak stress will not differ this much.
Regarding helium blisters, no risk exists for formation of such on the surface at these temperatures.
Smaller helium clusters inside tungsten can be formed in the environment at ESS, the deterioration of mechanical properties can be quite large due to this.
The risk of larger helium cluster forming in tungsten are small at these temperatures.}},
author = {{Fredriksson, Allan}},
language = {{eng}},
note = {{Student Paper}},
series = {{ISRN LUTFD2/TFME-22/5044-SE(1-80)}},
title = {{A molecular dynamics study on the influence of defects on tungsten material properties}},
year = {{2022}},
}