simulations of morphological instabilities and dendritic solidification is given first, in order to put our work into perWe present a front-tracking method to simulate time dependent two-dimensional dendritic solidification of pure substances. The spective. method is based on a finite difference approximation of the heat The process of solidification of a pure substance can equation and explici...

Aluminum alloy welding suffers from problems such as solidification cracking and hydrogen-induced porosity, which are sufficiently severe to limit its potential applications. Because mitigated porosity incidence and solidification cracking are observed in aluminum welds using double pulsed gas metal arc welding (DP-GMAW), a comprehensive review of the mechanism is necessary, but absent from the...

The Electroslag Remelting (ESR) process works with a consumable electrode, which is melted through a slag layer into a water-cooled mould applying alternating electric current. The ESR process produces large ingots of high quality, by controlled solidification and chemical refinement. It is important to predict, how certain process parameters affect the structure and chemical composition of the...

This thesis deals with the heat evolution during solidification and its relation to the formation of porosity. It intends to improve the current understanding of the formation of porosity in cast materials with special interest in nodular cast iron and the spray forming process. Two different systems, a Fe-based alloy, Cast iron, and a Ni-based alloy, Inconel 625, are examined. The effect on th...

Borate concentrated wastes generated from liquid waste evaporator of 12 pressurized water reactors (PWRs) have been processed to be dry using concentrated waste drying system (CWDS) in Korea. Borate wastes had been stabilized or solidified using paraffin as a binder since 1995, but the solidification process is stopped and concentrated wastes are just stored in drums and on standby at present b...

In the past 50 years, there has been increasing interest-both theoretically and experimentally-in the problem of pattern formation of a moving boundary, such as a solidification front. One example of pattern formation is that of irregular eutectic solidification, in which the solid-liquid interface is non-isothermal and the interphase spacing varies in ways that are poorly understood. Here, we ...

Dendrite sidebranch detachment is an important fragmentation mechanism during the solidification of alloys. The detachment occurs at the junction between a sidearm and its parent stem. While this pinching process is driven by capillarity, the presence of solidification opposes the instability. Using a simple numerical model of a single sidearm, we are able to capture the essential dynamics of d...

Research involving the interaction of flow with morphological instability during directional solidification of binary alloys is reviewed. In general, flow may arise during the solidification process from thermal and solutal buoyancy, changes in density upon solidification, thermocapillary forces at free boundaries, or external forcing of the system. We focus primarily on the last of these, givi...

Purpose: The casting-mould system is considered. Additionally, it is assumed that part of internal parameters determining the course of thermal processes, e.g. volumetric specific heat of mould, mould thermal conductivity, casting thermal conductivity and the like is unknown. Formulated in this way an inverse problem can be solved using different methods and in this paper the possibility of evo...

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...