We present theoretical studies of syntectic and monotectic solidification scenarios. Steady-state solidification along the liquid-liquid interface in a syntectic system is considered by means of a boundary-integral technique developed previously. We study the case of small asymmetry of the pattern and extract from the results the scaling relations in terms of the undercooling and the asymmetry ...

Phase change problems form an integral part of several manufacturing and materials processing applications. Such problems are computationally challenging because of the presence of multiple length scales and morphologically complex interfaces. In this work, we address some of those challenges through a generalized algorithm for computational modelling of solidification processes of binary alloy...

Directional solidification of metal-gas eutectic (Gasar) is a novel process for making regular porous metals. This process is based on a solid-gas eutectic reaction involving a gaseous medium and a metal or a ceramic phase, and allows an easy control of the porosity, such as its pore size, pore orientation and morphology in a wide range by properly adjusting its melting and solidification condi...

Here we show theoretically that the history of solid growth during ‘‘rapid’’ solidification must be S-shaped, in accord with the constructal law of design in nature. In the beginning the rate of solidification increases and after reaching amaximum it decreasesmonotonically as the volume of solid tends toward a plateau. The S-history is a consequence of four configurations for the flow of heat f...

In many scientific and engineering problems the solidification of an alloy leads to a highly convoluted crystalline matrix modeled as a thermodynamically controlled reactive porous medium called a mushy layer. We analyze the interaction of an external shear flow with a solidifying mushy layer through a corrugated mush–liquid interface. We find that the external flow can drive forced convective ...

The paper by Karma and Tourret (this volume) in this special issue focuses on multiscale modeling approaches ranging from atoms to microstructure. In the present one, the most recent and significant modeling contributions dealing with the scale of solidification from microstructure to grain structure are briefly reviewed. The paper also covers modeling of defect formation during the last stage ...

A two-dimensional thermal elasto-plastic numerical model is developed by finite element method to analyze and compare the mechanical driving factor for heat affected zone (HAZ) liquation cracking during laser welding and hybrid laser-arc welding techniques. Calculations of transient temperatures and cooling rates are used in conjunction with solidification theory to analyze weld pool characteri...

Microcasting Shape-Deposition-Manufacturing is an approach to Solid-Freeform-Fabrication (SFF) process which is a novel method for rapid automated manufacturing of near-net-shape multi-material parts with complex geometries. By this method, objects are made by sequentially depositing molten metal droplets on a substrate and shaping by a CNC tool, layer by layer. Important issues are concerned w...

Mathematical models and associated numerical techniques have been developed to investigate the complicated transport phenomena in spot hybrid laser-MIG keyhole welding. A continuum formulation is used to handle solid phase, liquid phase, and the mushy zone during the melting and solidification processes. The volume of fluid (VOF) method is employed to handle free surfaces, and the enthalpy meth...