Initiation and growth of short fatigue cracks in austenitic Sanicro 25 steel

0492026 - ÚFM 2019 RIV US eng J - Journal Article
Mazánová, Veronika - Polák, Jaroslav
Initiation and growth of short fatigue cracks in austenitic Sanicro 25 steel.
Fatigue and Fracture of Engineering Materials and Structures. Roč. 41, č. 7 (2018), s. 1529-1545. ISSN 8756-758X. E-ISSN 1460-2695
R&D Projects: GA MŠMT LM2015069; GA MŠMT(CZ) LQ1601; GA MŠMT LM2015069; GA ČR GA15-08826S; GA ČR(CZ) GA13-23652S
Institutional support: RVO:68081723
Keywords : austenitic steel * crack growth * crack growth coefficient * crack initiation * EBSD * equivalent crack
OECD category: Audio engineering, reliability analysis
Impact factor: 2.555, year: 2018

Austenitic heat‐resistant stainless steel Sanicro 25, often used in energy production
installations, was cyclically strained at room temperature, and initiation
and growth of short fatigue cracks have been studied. Cylindrical specimens
with pre‐existing shallow notch were cyclically strained under constant total
strain amplitudes, while the surface relief, crack initiation, and short crack
growth were observed, in‐situ, using optical and electron microscopes.
Persistent slip markings were found to be the principal locations where natural
fatigue cracks initiated. The character of the crack paths of short cracks was
studied using SEM and EBSD techniques. The results exhibit prevailing
transgranular crack growth, ie, along the persistent slip markings within the
grains. The growth of the largest cracks in the central part of the shallow notch
was measured for different applied strain amplitudes. Because the coalescence
of initiated cracks plays a significant role during crack growth, the use of the
“equivalent crack” concept gives adequate results in the description of the crack
growth rate. The crack growth law of short cracks was established and
compared with the Manson‐Coffin law of the material.
Permanent Link: http://hdl.handle.net/11104/0286799