Combinatorial analysis of model superalloys with varying Co/Ni ratio and γ′-content

Combinatorial methods using composition gradients are valuable tools for the accelerated development of novel alloys. A key challenge for structural metals is ensuring specimens are large enough for representative microstructure and property development. Surface-laser-intermixing is a novel method that allows the synthesis of such specimens on the mm-cm scale while requiring only arc-melted feedstock. Herein, this method is applied for the investigation of a model superalloy system between Ni- and Co-based compositions with varying γ′-fractions. The high energy input during remelting facilitates a melt pool depth of > 1 mm with only minor deviations of the compositions from the designed path through the system. The observed microstructure is in agreement with the literature-known phase stability. Microhardness measurements indicate the highest mechanical strengths in Ni-rich two-phase γ/γ′ compositions with medium to high γ′-fractions. This study focuses on the methodological development of surface-laser-intermixing, limiting mechanical property assessment to microhardness. The results establish a basis for more comprehensive material library characterization in future work. A unique feature of this method is the inexpensive and time-efficient creation of large composition gradients and the large amount of data that can be obtained from the resulting materials libraries. The data supporting the findings of this study are openly available in Zenodo at https://doi.org/10.5281/zenodo.17417500 . • Surface-laser-intermixing enables fast synthesis of compositionally graded alloys. • Crack-free superalloy gradients created despite complex multi-element system. • Microstructure–hardness correlations revealed across Co/Ni compositional paths. • Method-focused study establishes surface-laser-intermixing for structural alloys. • Laser-intermixed libraries support bulk-scale, high-throughput alloy screening.