A multiscale nonequilibrium model for melting of metal powder bed subjected to constant heat flux

TL;DR

This paper presents a multiscale nonequilibrium numerical model for metal powder bed melting under constant heat flux, accounting for volume shrinkage and analyzing temperature evolution and melting dynamics.

Contribution

It introduces a novel multiscale nonequilibrium model with volume shrinkage effects, solved via an implicit finite difference method, to study melting behavior of metal powder beds.

Findings

Liquid and mushy zones form during melting.

Higher initial porosity or temperature accelerates melting.

Particle size has minimal impact on melting process.

Abstract

A multiscale numerical model based on nonequilibrium thermal effect for melting of metal powder bed subjected to constant heat flux is developed. The volume shrinkage due to density change is taken into account. The nonequilibrium model is discretized by an implicit finite difference method and solved numerically using an iterative tri-diagonal matrix algorithm. The evolutions of powder bed surface temperature and various interfacial locations as well as the melting temperature range during the melting process are investigated. The results show that liquid region, upper and lower parts of mushy zone are formed on the top of unsintered zone as the melting progresses. The duration of the preheating stage shortens and the melting rate accelerates as the initial porosity or initial temperature increases while particle size has much less effect on the melting process. The parametric study shows the melting temperature range of the powder bed widens with increasing initial porosity, decreasing initial temperature or increasing particle size.