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. 6. (a) survey image of FIB milled micro bending beam to measure the interface stability between Si 3 N 4 ceramic particle and matrix after 50T + 5R HPT, (b) detail of the interface to test, a porosity in the particle is visible, (c) after testing the porosity in the particle was identified to a pre-fracturing. The crack entered the particle during the in situ bending test. The matrix proved to be bonded very well to the particle.

Pragnell et al. Prangnell et al. (1996) came to the conclusion that the high hydrostatic stresses during HPT suppress any plastic flow in highly dense particle clusters up to very high plastic strain levels. The denser particle clusters behaved like a single hard unit. These particle-like clusters were eroded by the matrix during HPT.