“…In Joly et al [27], the characterization was done with 25 mm thick C(T) specimens, whereas in this study the characterization was done with 5 mm thick SE(B) specimens. The larger specimen size yields a larger plastic deformation zone, compared to the smaller specimen, and proportionally, a larger part of the plastic deformation zone is in the weld metal, which can alter the stress response ahead of the crack [56,57]. The differences in the stress response can cause some variation in the obtained fracture toughness and be a reason why the brittle fracture initiation did not occur in all cases at the fusion boundary of the larger specimens.…”