The invention relates to a blisk segment for a gas turbine, comprising at least one first blade having an airfoil, a leading edge, a trailing edge, a blade root, a suction side and a pressure side, a pedestal, and a first fillet having a device for influencing crack growth. The robustness of the gas turbine is improved in accordance with the invention in that, at the leading edge of the first blade, at least on the first fillet, a first surface structure is arranged and interacts with the crack-influencing device for influencing crack growth and for flow influencing.