Development of advanced P/M Ni-base superalloys for turbine disks

Abstract

Abstract. In the process of evolution of powder metallurgy in Russia the task permanently formulated was the following: to improve strength properties of P/M superalloys without application of additional complex HIPed blanks deformation operation. On the other hand development of a turbine disk material structure to ensure an improvement in aircraft engine performance requires the use of special HIP and heat treatment conditions. To ensure maximum strength properties of disk materials it is necessary to form a structure which would have optimum size of solid solution grains, γ -phases and carbides. Along with that heating of the material up to a temperature determined by solvus of an alloy ensures a stable and reproducible level of mechanical properties of the disks. The above-said can be illustrated by successful mastering of new complex-alloyed VVP-class superalloys with the use of powder size −100 µm. Application of special HIP and heat treatment conditions for these superalloys to obtain the desired grain size and the strengthening γ -phase precipitates allowed a noticeable improvement in ultimate tensile strength and yield strength up to ≥1600 MPa and ≥1200 MPa respectively. 100 hrs rupture strength at 650• C and 750• C was improved up to 1140 MPa and 750 MPa respectively. P/M VVP nickel-base superalloys offer higher characteristics in comparison with many superalloys designed for the same purposes. HIPed disc compacts manufactured from PREP-powder have a homogeneous micro-and macrostructure, a stable level of mechanical properties.Advanced disk materials are the base for creation of fifth generation aircraft engines and also form scientific anticipative reserve for development of high technologies in the field of military and civil aircraft. The use of new high-strength high-temperature materials in gas-turbine engines allows one to improve power and service life of the engines and thereby to improve efficiency and reliability of aircraft.From the very outset of the development of the powder metallurgy in Russia the purpose was to produce as-HIP large-size P/M Ni-base superalloy disk blanks (Fig.

Structure Formation and Tribological Properties of Mo-Si-B-Hf Electrospark Coatings Based on Mo2Ni3Si Laves Phase

“…The EP741NP alloy is a powder complex alloy used in aircraft and spacecraft engine building [1]. Due to its high strength characteristics and wear and creep resistance, this high-temperature heat-resistant nickel alloy is applied to manufacture gaskets for the detachable connections in liquid propellant rocket engines, as well as disks, shafts and other heavy-duty components operating at temperatures up to 750 • C [2,3].…”