Couples and pairs formation-thermodynamic and kinetic modelling applied to Al-Mg-Si

0506813 - ÚFM 2020 RIV GB eng J - Journal Article
Svoboda, Jiří - Shan, Y. V. - Kozeschnik, E. - Fischer, F D.
Couples and pairs formation-thermodynamic and kinetic modelling applied to Al-Mg-Si.
Modelling and Simulation in Materials Science and Engineering. Roč. 25, č. 6 (2017), č. článku 065011. ISSN 0965-0393. E-ISSN 1361-651X
R&D Projects: GA ČR(CZ) GA15-06390S
Institutional support: RVO:68081723
Keywords : grain-boundary diffusion * self-consistent model * solid-solutions * alloys * precipitation * behavior * 1st-principles * simulation * elements * modelling * thermodynamic extremal principle * bulk diffusion * kinetics * aluminium alloys * cluster-assisted nucleation
OECD category: Thermodynamics
Impact factor: 1.793, year: 2017
Method of publishing: Limited access
https://iopscience.iop.org/article/10.1088/1361-651X/aa76cf

Kinetics of formation of couples (B-C) and pairs (B-B, C-C) is studied in an alloy with B-atoms and C-atoms as dilute solutes and A-atoms as solvent. The trapping concept, allowing division of the system into subsystems, the Bragg-Williams approximation used for the configurational entropy of each subsystem, and the thermodynamic extremal principle are applied in the model. The derived equilibrium conditions provide an extended Oriani-type equation. The kinetics of couples and pairs formation is given by explicit ordinary differential equations for the concentrations of couples and pairs allowing calculation of all relevant state variables. The concept is applied to an Al-Mg-Si system with the bonding energy terms EBB, ECC, EBC taken from ab-initio calculations. The presence of excess vacancies that are eventually frozen in by instant quenching as well as their subsequent annihilation influence the formation kinetics in a decisive way.
Permanent Link: http://hdl.handle.net/11104/0300806