Hot deformation behaviour of sintered cobalt
Hot deformation of sintered cobalt during hot compression testing was investigated in the temperature range of 700–1000 °C and at strain rates ranging from 0.0005 to 0.1 s-1. Cobalt underwent considerable dynamic recrystallization (DRX) during hot deformation, with stress-strain flow curves exhibiti...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/402798 |
| Acceso en línea: | https://hdl.handle.net/2117/402798 https://dx.doi.org/10.1016/j.jmrt.2023.10.291 |
| Access Level: | acceso abierto |
| Palabra clave: | Cobalt Materials at high temperatures Cobalt alloys WC-Co hardmetals Phase transformation Plasticity High temperature properties Deformation mechanism map Materials a altes temperatures Àrees temàtiques de la UPC::Enginyeria dels materials |
| Sumario: | Hot deformation of sintered cobalt during hot compression testing was investigated in the temperature range of 700–1000 °C and at strain rates ranging from 0.0005 to 0.1 s-1. Cobalt underwent considerable dynamic recrystallization (DRX) during hot deformation, with stress-strain flow curves exhibiting one or several peaks followed by significant flow softening and leading to a steady-state stress. Constitutive equations were used to derive the flow stress behaviour. A physically based model to describe the strain rate as a function of stress was suggested for temperatures ranging between 775 and 1000 °C. In this case, a creep exponent (n) of 5 indicated that the deformation mechanism was controlled by the glide and climb of dislocations. The activation energy coinciding with the one for self-diffusion of ferromagnetic cubic cobalt implied a diffusion-controlled mechanism and the presence of face-centered cubic (FCC) cobalt during deformation. Interestingly, the results at 700 °C could not be perfectly fitted to this model and exhibited a higher resistance to deformation. This revealed that the glide and climb deformation mode was close to the transition where glide mode was dominant, and thus mostly glide occurred at 700 °C, especially for the largest strain rates. |
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