Combining Experiments and Atom Probe Tomography-Informed Simulations on γ′ Precipitation Strengthening in the Polycrystalline Ni-Base Superalloy A718Plus

Kirchmayer A, Lyu H, Pröbstle M, Houlle F, Förner A, Huenert D, Göken M, Felfer P, Bitzek E, Neumeier S (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Advanced Engineering Materials Wiley

DOI: 10.1002/adem.202000149

Abstract

The strength of superalloys is strongly influenced by γ′ precipitates, whose size and volume fraction which can be adjusted by heat treatments. According to classical precipitation strengthening models, an increasing precipitate diameter should lead to a transition from weak to strong coupling of the dislocation pairs that form superdislocations in the γ′ phase. We show that long-term annealing of the Ni-base superalloy A718Plus at 670 and 680 °C increases the alloy's strength without significantly changing the grain size and η fraction. To understand the effect of the slight increase in γ′ size, detailed atom probe tomography (APT) was performed. Here, different field evaporation rates of the phases strongly affect the determination of the volume fraction when using the usual isosurface construction. This can be mitigated by considering the number density of atoms inside and outside the γ′ precipitates. Using an approximation of the precipitate shapes and arrangements from the APT data in atomistic simulations revealed that precipitate shearing by both, weakly and strongly coupled dislocations can occur in the same sample due to the wide distribution of precipitate sizes. These results highlight the need for advanced strengthening models that take into account the γ′ size distribution.

Authors with CRIS profile

Andreas Kirchmayer Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Hao Lyu Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Martin Pröbstle Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Frederic Houlle Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Andreas Förner Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Mathias Göken Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Peter Felfer Professur für Atom Probe Tomography Erik Bitzek Professur für Datenbasierte Materialmodellierung Steffen Neumeier Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)

Additional Organisation(s)

Professur für Datenbasierte Materialmodellierung Professur für Atom Probe Tomography Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)

Related research project(s)

Microscopic Origins of Fracture Toughness (microKlc) Microscopic Origins of Fracture Toughness May 1, 2017 - April 30, 2022 Atomistic simulations of elementary dislocation processes in coherent and semi-coherent y/y'-microstructures (C03) (SFB/TRR 103) TRR 103: Vom Atom zur Turbinenschaufel - wissenschaftliche Grundlagen für eine neue Generation einkristalliner Superlegierungen Jan. 1, 2012 - Dec. 31, 2019 In-situ nanomechanics and FIB tomography of thin films (EXC315 EAM (A2-3)) Exzellenz-Cluster Engineering of Advanced Materials Nov. 1, 2012 - Oct. 31, 2017

Involved external institutions

Rolls-Royce Deutschland Ltd & Co KG DE Germany (DE)

How to cite

APA:

Kirchmayer, A., Lyu, H., Pröbstle, M., Houlle, F., Förner, A., Huenert, D.,... Neumeier, S. (2020). Combining Experiments and Atom Probe Tomography-Informed Simulations on γ′ Precipitation Strengthening in the Polycrystalline Ni-Base Superalloy A718Plus. Advanced Engineering Materials. https://doi.org/10.1002/adem.202000149

MLA:

Kirchmayer, Andreas, et al. "Combining Experiments and Atom Probe Tomography-Informed Simulations on γ′ Precipitation Strengthening in the Polycrystalline Ni-Base Superalloy A718Plus." Advanced Engineering Materials (2020).

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