0531691 - ÚFM 2021 RIV CH eng C - Konferenční příspěvek (zahraniční konf.)
Polák, Jaroslav
Initiation and Early Growth of Fatigue
Cracks.
TMS 2019 148th Annual. Cham: Springer, 2019, s. 1125-1135. The Minerals, Metals & Materials Series. ISBN 978-3-030-05861-6. ISSN 2367-1181.
[TMS 2019 - Annual Meeting and Exhibition of The Minerals, Metals and Materials Society /148./. San Antonio (US), 10.03.2019-14.03.2019]
Grant CEP: GA MŠMT LM2015069; GA MŠMT(CZ) LQ1601
Institucionální podpora: RVO:68081723
Klíčová slova: Crack initiation * Crack growth * Damage mechanism
Obor OECD: Materials engineering
DOI: https://doi.org/10.1007/978-3-030-05861-6_109

Experimental evidence concerning the mechanism of initiation and early
growth of short cracks are studied using FESEM, FIB and STEM observations of the
surface of fatigued specimens of several f.c.c.metals. The true shape of persistent slip
markings with high resolution is obtained on FIB cuts and using lamella milled on the
surface. Thick extrusions and parallel thin crack-like intrusions are typical feature
before crack initiates from the tip of the intrusion. STEM also reveals the relation of
the surface relief and internal structure of the material showing in copper ladder-like
dislocation structure. The shape of the persistent slip markings is confronted with the
predictions of the recent theoretical models. Study of the short crack growth and its
kinetics shows high density of initiated surface cracks and proves the acceleration of
the crack growth rate due to linkage of principal crack with initiated surface cracks.
Fatigue life is determined by the growth of short cracks and short crack growth law
is equivalent to the Manson–Coffin law.

Trvalý link: http://hdl.handle.net/11104/0311462