This study employs an integrated experimental–numerical approach to assess the microstructural evolution of irradiation-induced defects in tungsten (W), which is being considered for fusion applications. A cluster dynamics (CD) model is utilized, and simulations are performed for irradiated disk-shaped compact tension W specimens. Experimental results indicate that the primary irradiation-induced defects in W at temperatures of 400 °C and 600 °C include dislocation loops (½<111> and <100>) and voids. Both experimental and CD results reveal that, at higher temperatures, the ½<111> loop population surpasses that of <100> loops, primarily due to the higher formation free energy of <100> loops compared to ½<111> loops. Given the high mobility of ½<111> loops in W, in the absence of traps, most ½<111> loops are absorbed by sinks or coalesce with <100> loops, leading to a reduced ½<111> loop population, as supported by the CD model. However, the introduction of traps results in an increased ½<111> loop population. The long-term evolution of loops demonstrates that the interaction between ½<111> and <100> loops facilitates the transfer of self-interstitial atoms between loops with different Burgers vectors, causing shifts in the populations of both loop types. The CD model reliably predicts the irradiation-induced microstructure in neutron-irradiated W, considering loops, voids and C15 clusters, while integrating the current state-of-the-art knowledge on radiation damage evolution and W energetics.
This study investigates how radiation damages the microstructure of tungsten, a material considered for fusion reactors. It uses experiments and computer simulations to understand the formation and behavior of defects like dislocation loops and voids in tungsten under different temperatures. The results show that the type and population of these defects depend on temperature, and the model can reliably predict the microstructural changes in irradiated tungsten.