Non-Contact Measurement of Thermal Diffusivity in Ion-Implanted Nuclear Materials

TL;DR

This paper introduces a non-contact method to measure thermal diffusivity in ion-implanted nuclear materials, revealing significant property changes relevant for fusion reactor design.

Contribution

It presents a novel non-contact measurement technique for thermal diffusivity in thin ion-implanted layers, addressing a key gap in nuclear materials research.

Findings

Ion-implantation reduces thermal diffusivity in tungsten

Alloying and gas retention further decrease thermal transport

Modeling accurately captures observed property changes

Abstract

Knowledge of mechanical and physical property evolution due to irradiation damage is essential for the development of future fission and fusion reactors. Ion-irradiation provides an excellent proxy for studying irradiation damage, allowing high damage doses without sample activation. Limited ion-penetration-depth means that only few-micron-thick damaged layers are produced. Substantial effort has been devoted to probing the mechanical properties of these thin implanted layers. Yet, whilst key to reactor design, their thermal transport properties remain largely unexplored due to a lack of suitable measurement techniques. Here we demonstrate non-contact thermal diffusivity measurements in ion-implanted tungsten for nuclear fusion armour. Alloying with transmutation elements and the interaction of retained gas with implantation-induced defects both lead to dramatic reductions in thermal diffusivity. These changes are well captured by our modelling approaches. Our observations have important implications for the design of future fusion power plants.