Correlation between embrittlement and bubble microstructure in helium-implanted materials

Evolution Law of Helium Bubbles in Hastelloy N Alloy on Post-Irradiation Annealing Conditions

“…In order to ensure the safe operation of MSR, it is of particular importance to clarify the helium bubble evolution caused by the diffusion of helium atoms during irradiation. The origin and mechanisms of the evolution of helium bubbles on reactor structural metal materials—especially their coarsening—were largely apprehended in the last thirty years [ 4 , 5 , 6 , 7 ]. It is worth noting that P. J. Goodhew [ 8 ] predicted that the mechanisms of “Ostwald ripening” and “migration and coalescence” may explain the coarsening of helium bubbles, according to calculations based on a growth rate equation.…”

Surface cracking on Σ3, Σ9 CSL and random grain boundaries in helium implanted 316L austenitic stainless steel

“…This occurs preferentially at the grain boundaries. At elevated temperatures, the helium bubbles grow rapidly resulting in weakening of the grain boundaries [1][2][3]. Under the influence of tensile stress, the formation of helium bubbles leads to intergranular fracture, so-called helium embrittlement [4,5].…”

Study by EELS of helium bubbles in a martensitic steel

“…The initial studies [5][6][7] aimed at understanding the mechanism of He bubble formation. The influence of implantation conditions on bubble size distributions [8] and the effect of implanted He on the mechanical properties [9] have been studied and it has been shown that helium can induce a severe loss of ductility [3,4]. Thus, it is important to understand the mechanisms involved in formation and growth of the bubbles.…”