PSI - Issue 77

Valeria Lemkova et al. / Procedia Structural Integrity 77 (2026) 279–291 Valeria Lemkova and Florian Schaefer / Structural Integrity Procedia 00 (2026) 000–000

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Fig. 1. Evolution of the hardness during ex situ isochronal heat increase test for Ni with (a) Si 3 N 4 and (b) with sand, T H denotes the homologous temperature.

Fig. 2. Evolution of the mean grain size determined from SE image analysis during the in situ heat treatment contrasted to the hardness evolution for Ni with (a) Al 2 O 3 and with (b) sand

EBSD grain size estimation su ff ers from the small grain size after HPT as shown in Fig. 5. Therefore, TKD measurements were performed at lamellas after Transmission Electron Microscopy (TEM) lift-outs in the SEM. Even the small grains can be indexed by TKD due to its improved lateral resolution compared to conventional EBSD. In a concave region of the particle the grain size is larger compared to the overall matrix and the convex regions of particle edges.