Exploitation of thermal gradients for investigation of irradiation temperature effects with charged particles

Chris D Hardie,Marin Vukšić,Andrew J London,Stjepko Fazinić,Tonči Tadić,Joven J H Lim,Rob Bamber

doi:10.1038/s41598-019-49585-0

Abstract

The effects of radiation damage on materials are strongly dependant on temperature, making it arguably the most significant parameter of concern in nuclear engineering. Owing to the challenges and expense of irradiating and testing materials, material property data is often limited to few irradiation conditions and material variants. A new technique has been developed which enables the investigation of radiation damage of samples subject to a thermal gradient, whereby a wealth of data over a range of irradiation temperatures is produced from a single irradiation experiment. The results produced are practically inaccessible by use of multiple conventional isothermal irradiations. We present a precipitation-hardened copper alloy (CuCrZr) case-study irradiated with a linear temperature gradient between 125 and 440 °C. Subsequent micro-scale post irradiation characterisation (nanoindentation, transmission electron microscopy and atom probe tomography) highlight the capability to observe mechanical and microstructural changes over a wide range of irradiation temperatures. We observed irradiation-softening in CuCrZr that did not occur due to irradiation-enhanced aging of the Cr-precipitates. Excellent reproducibility of the new technique was demonstrated and replicated irradiation-hardening data from several isothermal neutron irradiation studies. Our new technique provides this data at a fraction of the time and cost required by conventional irradiation experiments.

Highlights

For a vast range of applications, temperature is a primary factor concerning engineers when considering material performance in service and nuclear applications are exemplar to this
A new technique in which samples subject to a thermal gradient are irradiated with charged particles has been developed
This technique delivers a relatively fast and inexpensive means of investigating the effect of temperature on the radiation response of materials, which is useful for multiple applications from the validation of physics-based modelling and theory to the initial assessment of new/novel materials prior to further R&D investment

Summary

Introduction

For a vast range of applications, temperature is a primary factor concerning engineers when considering material performance in service and nuclear applications are exemplar to this. This paper describes a new approach that utilises subjecting materials with a thermal gradient along the sample length[11,12] to charged particle irradiation within an ion beam accelerator. In comparison with conventional isothermal irradiations[13,14], this technique provides samples for post irradiation experimentation (PIE) that include a large irradiation temperature range of interest from a single irradiation experiment with a fine thermal resolution. Relevant material with high thermal conductivity, where achieving the required thermal gradient is most challenging. This material exhibits a transition from irradiation hardening to irradiation softening at ~290 °C when subject to neutron irradiation[15], the irradiation response should vary substantially in the temperature range of interest

Methods

Results

Discussion

Conclusion