Deformation, diffusion and ductility during creep – continuous void nucleation and creep-fatigue damage
| Autor: | R. P. Skelton |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Austenite
Void (astronomy) Materials science Mechanical Engineering Metallurgy Metals and Alloys Nucleation 02 engineering and technology Strain rate Creep fatigue 021001 nanoscience & nanotechnology Condensed Matter Physics 020303 mechanical engineering & transports 0203 mechanical engineering Creep Mechanics of Materials Materials Chemistry Ceramics and Composites Stress relaxation Grain boundary Composite material 0210 nano-technology |
| Zdroj: | Materials at High Temperatures. 34:121-133 |
| ISSN: | 1878-6413 0960-3409 |
| DOI: | 10.1080/09603409.2016.1252888 |
| Popis: | It is shown that the assumption of unit (negative) slope in the well known Monkman–Grant plot of time to failure against minimum creep rate is too restrictive. By acknowledging observed slopes in the range 0.8–1, a ductility–strain-rate relation is deduced where ductility decreases with reducing strain rate. This in turn has implications for the ductility exhaustion method as applied during stress relaxation in the dwell period of low cycle fatigue tests of austenitic steels at elevated temperature. The simple method is used to calculate the cyclic creep damage in typical tests on austenitic steels in the region 550–650 °C and is compared to other calculations as employed in the R5 high temperature assessment procedure. The assumption of a uniform nucleation rate of grain boundary voids with creep strain goes some way to predicting the slope of the ductility–strain-rate relation. Both the ‘unconstrained’ and ‘constrained’ (lower shelf) regions of void growth are discussed. |
| Databáze: | OpenAIRE |
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