A first stage turbine disk section for a gas turbine engine, including a centrally disposed disk hub having an integrally-formed, radially outwardly extending web terminating at an outer end. The disk hub has a convex, curved hub surface exposed to high pressure, high temperature compressor bleed and discharge gases during engine operation, and the convex, curved hub surface acts to reduce the axial constraint at the location of peak axial stress, thereby mitigating the formation of undesirable …