Extrusions and intrusions in the cyclic plastic zone of the growing fatigue crack in polycrystalline copper

0578316 - ÚFM 2025 RIV GB eng J - Journal Article
Polák, Jaroslav - Jadlovský, Dan - Kruml, Tomáš
Extrusions and intrusions in the cyclic plastic zone of the growing fatigue crack in polycrystalline copper.
International Journal of Fatigue. Roč. 179, Feb (2024), č. článku 108063. ISSN 0142-1123. E-ISSN 1879-3452
R&D Projects: GA MŠMT LM2015069; GA MŠMT(CZ) LQ1601
Institutional support: RVO:68081723
Keywords : Persistent slip markings * Extrusions * Intrusions * Cyclic plastic zone * Intergranular crack path
OECD category: Materials engineering
Impact factor: 6, year: 2022
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S0142112323005649?via%3Dihub

Surface relief in the tip and along the path of a growing fatigue crack in polycrystalline copper has been observed and analyzed. A crack started from a semicircular notch in a prismatic specimen cycled with constant strain amplitude. In the notch tip and along the crack path on both sides of the specimen the surface relief of the grains was characterized by a high density of the PSMs belonging to two, up to three slip systems. Extrusions and intrusions of these PSMs intersect forming specific surface relief. Similar surface relief, corresponding to the grain boundary surface, has arisen on the fracture surface. It means that in the persistent slip bands inside the crystal, the material is pushed towards the neighboring grains or removed from the grain boundary (analogically to extrusions and intrusions on the surface). This mass transfer locally increases stresses on the grain boundaries creates discontinuities and weakens grain boundaries. Such novel mechanism of intergranular fatigue crack growth is discussed. The suggestion of an intergranular crack growth mechanism agrees with the predominantly intergranular crack path of the growing fatigue crack.
Permanent Link: https://hdl.handle.net/11104/0352648