Crack Initiation in Austenitic Stainless Steel Sanicro 25 Subjected to Thermomechanical Fatigue
| Autor: | Roman Petráš, Viktor Škorík, Jaroslav Polák |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Austenite
0209 industrial biotechnology Materials science Scanning electron microscope Metallurgy Oxide 02 engineering and technology engineering.material Condensed Matter Physics Atomic and Molecular Physics and Optics chemistry.chemical_compound Cracking 020303 mechanical engineering & transports 020901 industrial engineering & automation 0203 mechanical engineering chemistry mental disorders Crack initiation engineering General Materials Science Grain boundary Austenitic stainless steel Layer (electronics) |
| Zdroj: | Solid State Phenomena. 258:273-276 |
| ISSN: | 1662-9779 |
| DOI: | 10.4028/www.scientific.net/ssp.258.273 |
| Popis: | Thermomechanical fatigue experiments were performed with austenitic stainless Sanicro 25 steel. Several amplitudes of mechanical strain in a wide temperature interval (250-700 °C) were applied to the specimens. Mechanical response was recorded and fatigue lives were obtained. Scanning electron microscopy combined with FIB technique was used to study the mechanism of crack initiation in in-phase and in out-of-phase thermomechanical cycling. Different mechanisms of the crack initiation were found in these two types of loading. During in-phase loading fatigue cracks start in grain boundaries by cracking of the oxide. Cracks grew preferentially along grain boundaries which resulted in rapid crack initiation and low fatigue life. In out-of-phase loading multiple cracks perpendicular to the stress axis developed only after sufficiently thick oxide layer was formed and cracked in low temperature loading half-cycle. The cracks in oxide allowed localized repeated oxidation and finally also cracking. The cracks grow transgranularly and result in longer fatigue life. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|