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MM: Fachverband Metall- und Materialphysik
MM 36: Topical Session: Advanced Nanomechanics – Accelerating Materials Physics from the Bottom II
MM 36.1: Topical Talk
Donnerstag, 12. März 2026, 15:45–16:15, SCH/A251
High-temperature micropillar compression for understanding dislocation-precipitates interactions in Ni-Based superalloys — •Subin Lee1, Sangwon Lee2, Pyuck-Pa Choi2, and Christoph Kirchlechner1 — 1Institute for Applied Materials, Karlsruhe Institute of Technology, Karlsruhe, Germany — 2Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
The mechanical role of plate-like μ phases, topologically close-packed (TCP) precipitates, in Ni-based single-crystal superalloys was investigated using bulk and in situ SEM micropillar compression, supported by electron microscopy and APT. The μ phase showed strong temperature-dependent behavior: it remained rigid at room temperature, enforcing single-slip deformation, but became more compliant at 500 °C through bending and non-basal shearing.
Although acting as local obstacles to slip, μ phases consistently lowered the CRSS of micropillars. This softening resulted from deformation within the μ phase and from microstructural changes in the surrounding γ/γ' matrix. APT revealed Ta enrichment at the μ/γ' interface, enhancing γ' strengthening, while elastic mismatch shifted slip traces away from the interface by tens of nanometers.
Overall, these results highlight the dual role of μ phases. This integrated understanding of μ-phase deformation, interfacial chemistry, and matrix softening provides a fundamental mechanistic understanding for how TCP precipitation shapes the high-temperature mechanical behavior of Ni-based superalloys.
Keywords: Micropillar compression; High temperature deformation; Dislocations; Ni-based superalloy; TCP phase