Large gas turbine blades made from separate cast segments of superalloys are disclosed. The turbine blade is designed such that bond lines between adjacent segments are placed in low stress regions of the blade. The cast superalloy segments of the blades are aligned and fitted together with specified tolerances. The turbine blade segments are then joined by transient liquid phase bonding, followed by a controlled heat treatment which produces the desired microstructure in the bond region. The method allows for the production of large, high quality turbine blades by joining small, high quality cast superalloy sections, in comparison with prior attempts to cast large turbine blades as single pieces which have produced very low yields and high individual component costs.