11310E500100 College of Engineering Seminar

TOPIC
▸　3th generation of CALPHAD unary phase data – example study of AlZn system

Abstract
❝　During the last decade, there has been renewed interest in the application of physically based models in the thermodynamic modeling of phase equilibria using the CALPHAD method valid down to 0K temperature. The currently selected approach is based on the critical assessment of experimental heat capacity data for pure elements using extended Einstein model description. This included the choice of Einstein temperatures for the stable crystalline phases and the liquid phase and assessed parameters describing additional contributions to the heat capacities. These data have not yet been comprehensively extended to model the thermodynamic properties of binary, ternary and multicomponent systems. This work examines the way in which the parameters of these physical models might vary with composition. This includes a method for defining the Einstein temperature for metastable phases of elements and its relation to the lattice stabilities and the variation of the Einstein temperature with composition to account for the dependence of excess entropy on composition. This approach is demonstrated on the Al-Zn system, which exhibits extensive regions of solid solution and complete miscibility in the liquid phase. The Einstein temperatures are derived for Al in the hcp phase and Zn in the fcc phase, along with parameters describing the variation of Einstein temperature with composition for the hcp, fcc and liquid phases.　❞

SPEAKER
▸　Dr. Ondřej Zobač 
▸　Institute of Physics of Materials, Czech Academy of Sciences, v.v.i., Brno, Czech Republic

HOST
▸　Prof. Sinn-Wen CHEN 
▸　Department of Chemical Engineering, National Tsing Hua University

TIME
▸　2024/10/22 (TUE) 13:20 ~ 15:10

VENUE
▸　Classroom 209, Chemical Engineering Building