The role of the stagnant-film thickness in mesoscopic modeling of equiaxed grain envelopes

4th International Conference on Advances in Solidification Processes

材料科学;物理学

Souhar, Youssef^1 ; De Felice, Valerio F.^1 ; Zalonik, Miha^1 ; Combeau, Hervé^1 ; Beckermann, Christoph^2

Institut Jean Lamour, CNRS, Université de Lorraine, Nancy Cedex

F-54011, France^1

Department of Mechanical and Industrial Engineering, University of Iowa, Iowa City

IA

52242, United States^2

关键词: Dendritic grains;    Envelope models;    Equi-axed grains;    Liquid-solid phase change;    Mesoscopic modeling;    Model parameters;    Phase field methods;    Solute concentration fields;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/117/1/012014/pdf
DOI  :  10.1088/1757-899X/117/1/012014

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The mesoscopic envelope model overcomes the limitations of phase-field methods. It can be applied at larger scales and can include fluid flow at reasonable computing cost. It consists of the description of a dendritic grain by an envelope that links the active dendrite branches. The grain is modelled as an evolving porous medium and the liquid-solid phase change and solute transport are modelled by volume-averaged equations. The velocities of the dendrite tips are determined by the local solute-concentration field in the proximity of the envelope through an analytical stagnant-film model. In this publication, we present our implementation of the model for a binary alloy and we discuss the influence of the stagnant-film thickness, the principal model parameter, on the predicted 3D equiaxed grains by comparisons with the scaling laws for binary-alloy dendrites obtained in recent experiments by Melendez and Beckermann.