GCP and TCP phases presented in nickel-base superalloys

The paper gives a short description of intermetallic phases presented in cast and wrought nickel based superalloys. Generally, the intermetallic phases presented in nickel based superalloys can be divided into three main groups: i - primary and secondary carbides; ii - GCP (Geometrically Close-Packed); and iii - TCP (Topologically Close-Packed). Of course, mentioned intermetallic phases have various influences on mechanical properties. Some of them have increasing strength or creep rupture life as well as fatigue properties. On the other hand, some act negatively to mechanical properties. Its influence strongly depends from morphology (shape or orientation in matrix), and quantity (e.g. small amount of delta phase Ni3Nb increases tensile strength and fatigue properties when situated on grain boundary of wrought IN 718 alloy) as well. Most of phases are presented after applied heat treatment, which commonly consist of solution annealing followed by artificial ageing. (C) 2016 Elsevier Ltd. All rights reserved.