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- Title
KINETIC CHARACTERIZATION OF AN AA8011 ALLOY NON-ISOTHERMALLY ANNEALED ABOVE 400°C.
- Authors
Luiggi Agreda, Ney José
- Abstract
Solid state reactions occurring in an Al-Fe-Si alloy are demonstrated through DSC measurements at temperatures above that of recrystallization, where Fe-rich precipitation phases coexist with processes of recrystallized grain growth. These complex reactions are deconvolved for analysis into individual reactions associated to each of the transformation mechanisms involved in the process. Symmetrically distributed Gaussian transfer functions (GTF) and asymmetric Weibull transfer functions (WTF) are used in the deconvolution; and each individual reaction is analyzed through both the Šesták-Berggren (SB) combined kinetic model and the isoconversional scheme, a linear regression determining each of the parameters. The study reflects the drawbacks of kinetic analysis based solely on the fitting of heat flow, as the patent dispersion of kinetic parameters clearly shows. This is corrected by adjusting the activation energy obtained by isoconversion methods. Three reactions are required when using GTF; whereas only two suffice when using WTF. The overall results show that reactions above 400°C occur primarily because of Fe diffusion, and that other reactions occurring in deformed samples have activation energies coinciding with energy diffusion at high-angle grain boundaries.
- Subjects
KIRKENDALL effect; TRANSFER functions; ALLOYS; GAUSSIAN function; ACTIVATION energy; GRAIN growth
- Publication
La Revista Latinoamericana de Metalurgia y Materiales, RLMM, 2019, Vol 39, Issue 1, p16
- ISSN
0255-6952
- Publication type
Article