Abstract: A disk for a BLISK rotary stage of a gas turbine engine includes a stub on the tapered circumferential surface of a turbine disk, the stub defining a weld joint surface on the radially outermost face of the stub. The weld joint surface follows the annulus curvature in axial and circumferential directions while remaining flat in a third direction. A blade is applied radially to the stub and linear friction welding of the blade to the stub is effected by oscillating the blade in said third direction while applying a welding force inwardly along the blade.

Abstract: A method of making a BLISK by linear friction welding, comprises providing a stub on the circumferential surface of a turbine disk and defining a weld joint surface on the radially outermost face of the stub. The weld joint surface follows the annulus curvature in axial and circumferential directions while remaining flat in a third direction. A blade is applied radially to the stub and linear friction welding of the blade to the stub is effected by oscillating the blade in said third direction while applying a welding force inwardly along the blade.

Abstract: A method of making an integrally bladed disc for a gas turbine engine, the disc having at least one blade the radially outermost surface of which is coated with a material harder than that of the blade, the method comprising the steps of: providing a forged disk blank of a first material; friction surfacing at least part of the circumference of the blank with a second material harder than the first material; and machining the blank so as to provide an integrally balded disc wherein the radially outermost surface of at least one blade is coated with said second material.

Abstract: A turbine compressor or turbine bladed disc assembly wherein the blades 6 include root portions 8 provided with opposed converging surfaces 9,10 and the disc 14 includes slots 11 provided with opposed diverging surfaces 12,13. In assembly the root portion 8 of a blade 6 is engaged in a slot 11 with abutting converging and diverging surfaces and the blade 6 is oscillated relative to the disc whilst pressure is applied radially to urge the root into close contact with the slot until melting temperature is reached whereupon the oscillatory motion is arrested and the pressure maintained as the converging and diverging surfaces coalesce. A hole 16 may be drilled through the assembled blade and disc assembly in order that communication may be made with cooling air passages in the blade.