Helium-ion-implantation in tungsten: Progress towards a coherent understanding of the damage formed and its effects on properties

Conference item

Tungsten is a likely material for divertor armour in fusion reactors. We describe recent progress combining multi-technique experiments with atomistic modelling to understand how injected helium interacts with displacement damage and modifies the physical properties of tungsten. Using X-ray micro-diffraction and laser-induced transient grating measurements, we observe both a lattice swelling and modulus change after helium implantation. Surprisingly, a fraction of a percent lattice expansion is associated with an order of magnitude larger reduction in elastic modulus. These observations are interpreted using a combined elasticity and density functional theory model. We also measure a large reduction of thermal diffusivity due to helium implantation. This can be explained in terms of the underlying damage microstructure using a new atomistic kinetic theory model. Together our observations and calculations allow us to begin to form a joined-up picture of helium-implantation-induced damage in tungsten and its diverse effects on microstructure and physical properties.

Authors: Hofmann, F; Nguyen-Manh, D; Mason, DR; Gilbert, MR; Dudarev, SL

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Host title: 2016 IUTAM Symposium on Nanoscale Physical Mechanics
• Journal: 2016 IUTAM Symposium on Nanoscale Physical Mechanics
• Publication date: 2017-06-22
• Acceptance date: 2016-04-24
• DOI: 10.1016/j.piutam.2017.03.040
• EISSN: 2210-9838
• Keywords: tungsten; helium; laue micro-diffraction; thermal transport; ion implantation; surface Acoustic Waves