Insights into the effect of ?'- or ??-precipitated phase types on resistance against harmful atoms of heterogeneous interface in nickel-based superalloys

To improve the service performances of nickel-based superalloys by controlling the type and proportion of precipitate phases, the resistances against harmful atoms (weakening effect caused by harmful atoms and capacity for hindering intrusion of harmful atoms) of the representative y-matrix/y0- or y00-precipitated phase heterogeneous interfaces (y-Ni/y0- Ni3Al, y-Ni/y0-Ni3Ti, and y-Ni/y00-Ni3Nb interfaces) was investigated. The results show that, the harmful atoms (H, O, and S atoms) can be stable adsorbed on heterogeneous interfaces and weaken the interfacial bonding strength, resulting in the fracture position change from y0- or y00 slab to interface during tensile deformation. Because of the minimum changes on interfacial bonding characteristics after the intrusion of harmful atoms, y-Ni/y00-Ni3Nb heterogeneous interface (HIy00 Ni3Nb) demonstrates the strongest resistance against weakening effect, presented as the smallest deterioration of interfacial ideal work of adhesion and tensile strength. Meanwhile, the energy barrier of harmful atoms diffusing along HIy00 Ni3Nb is much larger than those along HIy00 Ni3Al and HIy00 Ni3Ti, leading to a smallest diffusion coefficient for harmful atoms diffusing along HIy00 Ni3Nb. The result indicates HIy00 Ni3Nb also shows the strongest capacity for hindering the intrusion of harmful atoms. This phenomenon is attributed to the strongest interaction between harmful atoms on saddle point and the neighboring atoms on HIy00 Ni3Nb during the diffusion process. To summary, the Ni-based superalloys with y00-Ni3Nb as the main precipitated phase demonstrate the most promising properties in resistance against harmful atoms. This work not only contributes to the further improvement of Ni-based superalloys, but also provides the creative ideas for the research of other superalloys. & COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).