The effect of dissolved nitrogen on the fatigue behavior of Ti-6Al-4V
| Autor: | David Rugg, C. R. Collins, Felicity F. Dear, David Dye |
|---|---|
| Přispěvatelé: | Engineering & Physical Science Research Council (EPSRC), Engineering & Physical Science Research Council (E, The Royal Society |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Technology
Materials science Alloy Materials Science chemistry.chemical_element Materials Science Multidisciplinary 02 engineering and technology Plasticity engineering.material 01 natural sciences law.invention law Phase (matter) Ductility 0912 Materials Engineering Materials 0306 Physical Chemistry (incl. Structural) Science & Technology 010401 analytical chemistry Metallurgy Metals and Alloys 021001 nanoscience & nanotechnology Condensed Matter Physics Microstructure Nitrogen 0104 chemical sciences chemistry Mechanics of Materials engineering Metallurgy & Metallurgical Engineering Electron microscope 0210 nano-technology Bar (unit) 0913 Mechanical Engineering |
| Popis: | The effect of nitrogen additions on fatigue behavior has been examined in near-equiaxed, rolled Ti-6Al-4V bar. This is the first-time nitrogen content that has been systematically explored with respect to monotonic and cyclic properties in a Ti-6Al-4V alloy base composition. Nitrogen additions were found to increase the $$\beta $$ β -transus temperature and strength, but they decreased ductility, even in microstructures where some $$\beta $$ β phase remained. This carried across into both the low- and high cycle fatigue behavior; even small contents of 240 and 560 ppmwN caused reductions in both low cycle fatigue life and high cycle fatigue strength. In samples containing 240 and 560 ppmwN, a conventional striated fractographic appearance was observed, but a dramatic change to a macroscopically brittle fracture surface was observed at 1800 and 3600 ppmwN, but still with substantial evidence of plasticity at the microscale. Therefore, neither microstructure or fractographic examination, nor EDX-based compositional analysis in the electron microscope are necessarily a reliable indicator of an absence of deleterious nitrogen contamination. This is significant for the investigation of potentially nitrogen-contaminated surface-initiated cracks, either due to service or processing exposures. |
| Databáze: | OpenAIRE |
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