Coolable rotor blade assembly for an axial flow rotary machine

For a gas turbine engine, a coolable rotor blade assembly of the type formed of a hollow rotor blade having an inwardly facing wall and having a base which is adapted by an opening in the base surrounded by an inwardly facing seat to receive an impingement tube, the impingement tube being adapted by a face to conform to the seat, being spaced from the blade to form a cavity therebetween, and in fluid communication at a second pressure with a source for cooling fluid at a first pressure and with the wall of the blade through a plurality of holes and the cavity at a third pressure, the improvement which comprises:

• a fiber metal seal disposed between the seat of the blade and the face of the tube wherein the seal blocks the leakage of the cooling fluid between the tube and the blade to maintain the requisite pressure gradient across the tube to the wall for impingement cooling.