The local_nonequlibrium kinetics of growth of stoichiometric compounds under isothermal condition: phase_field approach

[摘要] The presence of line (stoichiometric) compounds in alloys of light metals greatly improves their mechanical and strength properties. The formation of Al2Y and Al3Y line compounds in a highly supercooled Al-Y melt is investigated using the phase field method and numerical modeling of the directional solidification of the melt. The main problem in the phase-field description of phase transitions in line compounds is finding the driving forces of these transitions. One of the possible ways to handle this problem is development of a thermodynamically consistent phase-field approach based on the minimization of the full Gibbs energy of the system, nonequilibrium thermodynamics and separation of diffusion processes in different phases. The resulting equations are analyzed in the equilibrium case. The model dynamics is examined numerically for the case of the one-dimensional problem of directional solidification of the Al-Y melt under isothermal condition. The analysis of the numerical solutions shows that initially the transformation of the melt from liquid to solid happens due to the driving forces of the phase transition, while further formation of the spatially-nonhomogeneous laminated structure is caused by the interfacial barriers.

[发布机构] Udmurt State University, Department of Matematics, Informatics and Physics, Izhevsk; 426034, Russia^1;Physical-Technical Institute of UrB RAS, Izhevsk; 426000, Russia^2

[效力级别] 计算机科学

[关键词] Interfacial barriers;Isothermal conditions;Laminated structures;Non equilibrium thermodynamics;One dimensional problems;Phase field methods;Phase-field approaches;Stoichiometric compound