A unified microscale parameter approach to solidification-transport process-based macrosegregation modeling for dendritic solidification: Part II. Numerical example computations

Abstract

This article, as the second part of the present work, applied the unified Φ-parameter-based micro/macrosegregation modeling, which was proposed and described in the first part, to two groups of alloy solidification systems. The first group is on closed simultaneous solidification systems of an Al-4.5 pct Cu alloy and a Fe-0.5 pct C based plain carbon steel to investigate the microscale solute-redistribution behaviors with different influential factors including the solid phase morphologies. A new solute-redistribution equation was derived from the present microscale unified Φ-parameter-based modeling, which includes more microscale dendrite-solidification features while preserving the simple function form equivalent to the well-known lever rule and the Scheil, Flemings-Brody, Clyne-Kurz, and Ohnaka models. In the second example computation group on a directionally solidified, bladelike casting system, a previous continuum model and the related PC-based codes developed by the present authors were extended and modified by incorporating the present microscale Φ-parameter approach to any extent of solid back-diffusion effects. Numerical simulations on the directional-solidification transport phenomena and micro/macrosegregation formations in a bladelike Al-4.5 pct Cu casting show the feasibility and the efficiency of the present solidification-transport process (STP)-based two-scale segregation model and the numerical methods.