Abnormal grain growth: a non-equilibrium thermodynamic model for multi-grain binary systems

0434270 - ÚFM 2015 RIV GB eng J - Článek v odborném periodiku
Svoboda, Jiří - Fischer, F. D.
Abnormal grain growth: a non-equilibrium thermodynamic model for multi-grain binary systems.
Modelling and Simulation in Materials Science and Engineering. Roč. 22, č. 1 (2014), Art. No. 015013. ISSN 0965-0393. E-ISSN 1361-651X
Institucionální podpora: RVO:68081723
Klíčová slova: grain boundary segregation * abnormal grain growth * theory * modelling * solute drag
Kód oboru RIV: BJ - Termodynamika
Impakt faktor: 2.167, rok: 2014

Abnormal grain growth as the abrupt growth of a group of the largest grains in a multi-grain system is treated within the context of unequal retardation of grain growth due to the segregation of solute atoms from the bulk of the grains into the grain boundaries. During grain boundary migration, the segregated solute atoms are dragged under a small driving force or left behind the migrating grain boundary under a large driving force. Thus, the solute atoms in the grain boundaries of large grains, exhibiting a large driving force, can be released from the grain boundary. The mobility of these grain boundaries becomes significantly higher and abnormal grain growth is spontaneously provoked. The mean-field model presented here assumes that each grain is described by its grain radius and by its individual segregation parameter. The thermodynamic extremal principle is engaged to obtain explicit evolution equations for the radius and segregation parameter of each grain. Simulations of grain growth kinetics for various conditions of segregation with the same initial setting (100 000 grains with a given radius distribution) are presented. Depending on the diffusion coefficients of the solute in the grain boundaries, abnormal grain growth may be strongly or marginally pronounced.
Trvalý link: http://hdl.handle.net/11104/0238483