Effect of grain size on self -healing behaviour of sensitized S304HCu stainless steel
| Autor: | P. Rajesh Kannan, E. Arthi, C. Sridivya, K. Devakumaran, V. Muthupandi |
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| Rok vydání: | 2018 |
| Předmět: |
Austenite
Materials science 020209 energy Kinetics Oxalic acid 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics Grain size chemistry.chemical_compound chemistry Creep Vacancy defect 0202 electrical engineering electronic engineering information engineering General Materials Science Grain boundary Composite material 0210 nano-technology Chromium carbide |
| Zdroj: | Materials Chemistry and Physics. 207:203-211 |
| ISSN: | 0254-0584 |
| DOI: | 10.1016/j.matchemphys.2017.12.012 |
| Popis: | S304HCu stainless steel is extensively used for superheater and reheater applications in power plants due to its superior creep strength and oxidation resistance which are derived from the coherently dispersed precipitates formed in austenite matrix. In addition to the beneficial precipitates, chromium carbide precipitates can also form. Formation of chromium carbide precipitates during service will lead to sensitization. In this investigation, S304HCu samples were solutionized at 1100 °C and 1200 °C for 1 h, and further aged at 750 °C for upto 400 h to introduce sensitization and subsequent healing. The influence of ageing time and grain size on the degree of sensitization (DOS) was evaluated by using oxalic acid and double loop electrochemical potentiodynamic reactivation (DLEPR) tests. DOS initially increased up to 10 h of ageing and subsequently was reduced due to healing and attained a steady value at 50 h. Faster and higher DOS was observed in coarse grain structure than in the fine grain structure. However, healing was largely delayed in coarse grained structure. The difference in solute and excess vacancy concentration and shifting of the nose in TTP curve were attributed to the difference in the kinetics of sensitization and healing. The extent of the attack on the grain boundary was analyzed using AFM. |
| Databáze: | OpenAIRE |
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