Composite turbine disc made by powder metallurgy - where two superalloy powders are successively degassed in vacuo and fed into rotating mould for hot isostatic pressing

摘要

Two metal powders (I, II) are each loaded into a doser. The two dosers are located on top of a hopper (a), into which powder (I) is fed and heated in vacuo for de-gassing before the powder is fed into a storage hopper (b). From hopper (b), powder (I) is fed into an evacuated mould fixed on a rotating table, and the centrifugal force causes powder (I) to form the periphery of a disk made in the mould. Powder (II) is next de-gassed in hopper (a), and is then fed via hopper (b) into the mould to form the hub of the disk. The rotation of the mould is then stopped, and the ould is sealed before being subjected to heat and pressure so a composited disk is obtd. where powder (I) forms the disk periphery surrounding a hub made of powder (II). The powders are degassed, and are not exposed to impurities while being used to fill a mould, which can then be subjected to hot isostatic pressing (HIP) to obtain disks with high densities.