Investigation of damage features of a turbo-disk

A turbo-disk made from GH2036 superalloy was damaged in service. Three damage modes took place on the back face of the disk: radial cracking at the rim slot; severe circumferential wear on the disk and a lot of radial short cracks normal to the wear marks; non-symmetry deformation and cracking of the edges of the bolt holes on the disk-hub. All the cracks on the disk propagated in intergranular mode. Overheating on the back face of disk resulting from the intense friction between the air-seal and the back face of disk was responsible for damage of the turbo-disk, which was reflected by the microstructure features. Most evidence points that the turbo-disk failed by a creep damage promoted by overheating.