| Titre : | High-temperature strength of compacted sub-micrometer aluminium powder (2011) |
| Auteurs : | C. Poletti, Auteur ; M. Balog, Auteur ; F. Simancik, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Acta materialia (Vol. 58 N° 10, Juin 2010) |
| Article en page(s) : | pp. 3781–3789 |
| Note générale : | Métallurgie |
| Langues : | Anglais |
| Tags : | Powder consolidation Aluminium Ultrafine-grained microstructure High-temperature deformation Grain boundary structure |
| Résumé : | Aluminium powders with a mean particle size of around 1 μm were compacted by cold isostatic pressing (CIP) and additional forging. The specimens are characterized by hot compression tests, dilatometry and metallography. A 3D interconnected structure of alumina films <5 nm in thickness is observed by transmission electron microscopy and field emission gun scanning electron microscopy; it is associated with the natural oxide skin which covers every aluminium powder and occupies around 3 vol.%. The compression tests are carried out in the range of 350–520 °C at strain rates of 0.003–3 s−1. The compressive strength was 100–150 and 130–180 MPa for the CIPed and forged samples, respectively. The low strain rate sensitivity m (<0.08) suggests that the alumina network forms a barrier, which suppresses any restoration mechanism across the grain boundaries as well as grain boundary sliding during hot deformation. The high strength of such compacted sub-micron Al powder is attributed to the conservation of a 3D alumina closed cell network filled with elastoplastic aluminium. |
| DEWEY : | 669 |
| ISSN : | 1359-6454 |
| En ligne : | http://www.sciencedirect.com/science/article/pii/S1359645410001667 |
