The controllable nuclear fusion, often described as "artificial sun," is a crucial frontier technology for achieving low-carbon emission in China. Tungsten (W), as a promising plasma-facing material for fusion reactors, exhibits outstanding properties, such as high melting point, high thermal conductivity, excellent sputtering erosion. However, the susceptibility to brittleness below a critical temperature, characterized as ductile-to-brittle transition (DBT), poses a serious challenge to their workability and performance in extreme environments.

Fig. 1. The DBT behavior of W/W-Re alloys

Historically, rhenium (Re) has been considered the most industrially relevant alloying element for improving the ductility of W by enhancing screw dislocation mobility. However, our researches indicate that Re alloying cannot be relied upon to toughen W. The Re-induced spatial debris at elevated temperature significantly hampers the mobility of dislocations, which gradually increases the DBT temperatures of W-Re alloys. This discovery provides essential knowledge for optimizing the design and performance of refractory metals across a diverse range of applications.

This work has been published online in Acta Materialia with the title “Unveiling the Intrinsic Rhenium Effect in Tungsten”. Dr. Yu-Heng Zhang from the School of Materials, Xi'an Jiaotong University, is the first author of the paper, and Prof. Wei-Zhong Han is the corresponding author. This research was supported by the National Natural Science Foundation of China and the Shaanxi Science & Technology Innovation Project.

Paper Link: https://doi.org/10.1016/j.actamat.2023.119586