Nickel-based superalloys are currently the material of choice for use in high-temperature applications due to their excellent high-temperature strength. It is understood that many mechanisms contribute to this property, but debate exists regarding how to model these mechanisms and predict the overall strength. This review covers the different strengthening mechanisms occurring in polycrystalline Ni-based superalloys and how these may be modelled, with the aim of revealing the gaps in the literature. It is found that models for precipitation and coherency strengthening are particularly controversial, and a unified model for the yield strength of superalloys is missing from the literature. This is of commercial importance for the design of new alloys with superior mechanical properties to those currently available.
This review was submitted as part of the 2018 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged.
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precipitating alloys
hardened nickel alloys
hardened nickel-base alloy
(ordered Ni
Ti) precipitates
Nickel-base superalloys
Al with ternary addition of transition metal elements
hardened superalloy Nimonic PE16 in high-voltage electron microscopes
lattice misfit in superalloys—with special reference to the new 
-hardened cobalt-base superalloys
strengthened Co-base superalloys in the Co-W-Al-Ti quaternary system
interface width in a commercial nickel base superalloy studied by three-dimensional atom probe tomography
Al by alloying with zirconium
Al alloyed with iron additions
precipitating nickel-base alloys—II. Experiments
Al (
)
Al by ternary additions
Al
) precipitates in an advanced nickel-based superalloy
precipitating Ni-base alloys. Theoretical concept
precipitates in nickel-base superalloys
precipitate dispersion of polycrystals of a nickel-base superalloy
Al
Al
and AuCu type superlattices
Al: generalized peierls model in combination with ab initio electron theory
, Ni
Al, Ni
Ge and Fe
Ge: Peierls-Nabarro analysis starting from ab-initio GSF energetics calculations
Al
Al
and DO
compounds
-phases of the Ni-Al system
) precipitates formed at different cooling rates in an advanced Ni-based superalloy
O
particulate-reinforced aluminium matrix composites
precipitates