Permeability Measurements of 3D Microstructures Generated by Phase Field Simulation of the Solidification of an Al-Si Alloy during Chill Casting

Metals, vol. 11, pp. 1895

Abstract

The permeability of the semi-solid state is important for the compensation of volume shrinkage during solidification, since insufficient melt feeding can cause casting defects such as hot cracks or pores. Direct measurement of permeability during the dynamical evolution of solidification structures is almost impossible, and numerical simulations are the best way to obtain quantitative values. Equiaxed solidification of the Al-Si-Mg alloy A356 was simulated on the microscopic scale using the phase field method. Simulated 3D solidification structures for different stages along the solidification path were digitally processed and scaled up to generate 3D models by additive manufacturing via fused filament fabrication (FFF). The Darcy permeability of these models was determined by measuring the flow rate and the pressure drop using glycerol as a model fluid. The main focus of this work is a comparison of the measured permeability to results from computational fluid flow simulations in the phase field framework. In particular, the effect of the geometrical constraint due to isolated domain walls in a unit cell with a periodic microstructure is discussed. A novel method to minimize this effect is presented. For permeability values varying by more than two orders of magnitude, the largest deviation between measured and simulated permeabilities is less than a factor of two.

Authors 7

1. Markus Apel Aachen Access e.V

   Access

   Affiliation as printed

   ACCESS e.V, Intzestrasse 5, D-52072 Aachen, Germany

2. Gottfried M. LASCHET Aachen Access e.V

   Access

   Affiliation as printed

   ACCESS e.V, Intzestrasse 5, D-52072 Aachen, Germany

3. Wilhelm Jessen Aachen Institut of Aerodynamics (AIA)

   RWTH Aachen University

   Affiliation as printed

   Institut of Aerodynamics (AIA), RWTH Aachen University, Wüllnerstrasse 5a, D-52062 Aachen, Germany

4. Wolfgang Schröder Aachen Institut of Aerodynamics (AIA)

   RWTH Aachen University

   Affiliation as printed

   Institut of Aerodynamics (AIA), RWTH Aachen University, Wüllnerstrasse 5a, D-52062 Aachen, Germany

5. Jens Wipperfürth Aachen Institute of Plastics Processing

   RWTH Aachen University

   Affiliation as printed

   Institute of Plastics Processing (IKV), RWTH Aachen University, Seffenter Weg 201, D-52064 Aachen, Germany

6. Johannes Austermann Aachen Institute of Plastics Processing

   RWTH Aachen University

   Affiliation as printed

   Institute of Plastics Processing (IKV), RWTH Aachen University, Seffenter Weg 201, D-52064 Aachen, Germany

7. Christian Hopmann Aachen Institute of Plastics Processing

   RWTH Aachen University

   Affiliation as printed

   Institute of Plastics Processing (IKV), RWTH Aachen University, Seffenter Weg 201, D-52064 Aachen, Germany