A model for free growth of a lamellar eutectic dendrite with an incident flow

Abstract

A model for free growth of a lamellar eutectic dendrite with an incident flow was proposed for the breakdown of a planar solid/liquid interface into a dendritic contour due to a negative thermal gradient in an undercooled liquid. The model was used to predict the growth kinetics of an -Ni/NiSn eutectic dendrite with and without an incident flow in the growth direction. The modelling showed that free eutectic growth is not sensitive to the tip selection parameter of the eutectic dendrite, but is sensitive to incident flow of magnitude larger than eutectic growth velocities. While the larger incident flow increases the eutectic growth velocities generally, it has opposing effects on the interlamellar spacings depending on undercooling. The prediction of the model awaits experimental validation.This article is part of the theme issue 'From atomistic interfaces to dendritic patterns'.

The boundary integral theory for slow and rapid curved solid/liquid interfaces propagating into binary systems

“…The phase interface in such problems is assumed to be atomically rough with thickness of the order of several interatomic distances. Not discussing this problem in detail (see works on phase-field modelling [13][14][15][16][17][18][19][20][21][22][23][24][25][26]) we shall neglect this atomic roughness and assume a sharp interface on the macroscopic length scale. Methods of analytical and numerical description of the Stefan-type moving boundary problems can be classified as two problem-solving approaches: (i) to find the bulk temperature and solute concentration fields taking into account the phase interface conditions [9][10][11] and (ii) to formulate and solve the free-boundary problem for the phase interface function (deformation of the interfacial surface) [27][28][29][30][31][32].…”

Off-Eutectic Growth Model for Solidifying Alloy from an Undercooled State

“…In what follows, the concentration effect on the off-eutectic alloy is measured by taking the diffusion coefficient change into account. In the present study, we consider the influence of the existence of primary phases, combining the theory of diffusion-controlled and diffusionless transformation [28] with using similar hypotheses as the classical theory [17][18][19][20][21][22]. Thus, considering the effect of the primary phase, a model for off-eutectic growth is derived and solved in comparison with the accessible experimental data.…”

“…Li et al [21] neglected solute trapping but incorporated kinetic and thermal undercooling into eutectic growth in the analysis of solidification in the bulk undercooled melt (LZ model). Gao [22] studied the growth kinetics of the eutectic dendrite in the presence of an incident flow based on the LZ model. Using the same hypotheses as the JH model, Senninger and Voorhees [23] proposed a model for eutectic growth in two-phase multicomponent alloys.…”

Modeling and simulation of heat/mass transport, nucleation and growth kinetics in phase transformations

“…It is well-known that phase and structural transformations occurring in metastable and heterogeneous materials attract the attention of researchers working in a broad range of theoretical and applied science varying from materials and condensed matter physics to biophysics and life science (see, among others, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]). This is explained by the fact that such transformations completely determine the concluding state of obtained materials, their structure, and properties.…”