treatment or electron beam methods an exemplary apparatus is schematically represented in fig4 an exemplary apparatus includes a hollow ceramic vessel 48 adapted for insertion of the unfinished dovetail 44 in this embodiment induction heating coils 50 are utilized to provide the requisite heat treatment alternate heating methods may be utilized for example it is contemplated that laser beams may be utilized to heat pre selected regions of the unfinished dovetail 44 alternately electron beam radiation may be utilized an important consideration is the rapidity with which the water quench can occur after heating those with skill in the art will appreciate that induction heating laser treatment or electron beam methods can provide a rapid controlled heating environment the temperature and duration of the heat treatment followed by adequate water quench impacts the resulting microstructure within the dovetail for example heat treatment below the beta solvus temperature followed by immediate quenching is a prerequisite for a bimodal microstructure heat treatment above the beta solvus temperature followed by immediate quenching results in martensitic microstructure the depth of the modified microstructure i e skin depth may be dependent on the duration of the heat treatment in general only the unfinished dovetail 44 is subjected to the additional heat treatment thus preserving the alpha beta structure of the airfoil 42 shown in fig5 fig6 and 7 respectively show the martensitic microstructure and the bimodal structure achieved in.