Nickel- and Cobalt-base Superalloys

Creep of single-crystal superalloys is governed by dislocation glide, climb, reactions and annihilation. Discrete three-dimensional (3D) dislocation dynamics (DDD) simulations are used to study the evolution of the dislocation substructure in a gamma/ gamma’ microstructure of a single-crystal superalloy for different climb rates and loading conditions. [more]
The precipitation of topologically close packed (TCP) phases is detrimental for the high temperature strength of high refractory Ni-based superalloys. The beneficial influence of Ru with respect to this so called instability is nowadays well accepted. [more]
This project deals with the origin of creep dislocations in a Ni-base, single crystal superalloy subject to creep at an intermediate stress and temperature. [more]
In this project we investigate the hydrogen distribution and desorption behavior in an electrochemically hydrogen-charged binary Ni-Nb model alloy. The aim is to study the role of the delta phase in hydrogen embrittlement of the Ni-base alloy 718. [more]
Ni-based superalloys are high-temperature materials employed e.g. in turbines. They gain their high strength by precipitation hardening. The unique thermal history encountered by the material during LAM, which includes rapid cooling from the melt, cyclical re-heating and/or an elevated processing temperature due to preheating, influences the number density and size distribution of the precipitates. For the same reason, unwanted defects, such as hot cracks, can occur in the material. [more]
In this project an integrated simulation strategy for studying primary static recrystallization was developed and applied to a single-crystal nickel-base superalloy. By using a crystal plasticity finite element approach, the driving force for nucleation and grain growth around a Brinell-type indent was modeled. [more]
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