Phase-Field Modelling of Bimodal Dendritic Solidification During Al Alloy Die Casting

Tracking the microstructural evolution during high-pressure die casting of Al-Si alloys is challenging due to the rapid solidification, varying thermal conditions, and severe turbulence. The process involves a transition from slower cooling in the shot sleeve to rapid cooling in the die cavity, resu...

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Main Authors: Maryam Torfeh, Zhichao Niu, Hamid Assadi
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Metals
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Online Access:https://www.mdpi.com/2075-4701/15/1/66
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author Maryam Torfeh
Zhichao Niu
Hamid Assadi
author_facet Maryam Torfeh
Zhichao Niu
Hamid Assadi
author_sort Maryam Torfeh
collection DOAJ
description Tracking the microstructural evolution during high-pressure die casting of Al-Si alloys is challenging due to the rapid solidification, varying thermal conditions, and severe turbulence. The process involves a transition from slower cooling in the shot sleeve to rapid cooling in the die cavity, resulting in a bimodal dendritic microstructure and nucleation of new finer dendrite arms on fragmented externally solidified crystals. In this study, a two-dimensional phase-field model was employed to investigate the solidification behaviour of a hypoeutectic Al-7% Si alloy during high-pressure die casting. The model is based on thermodynamic formulations that account for temperature changes due to phase transformation heat, thermal boundary conditions, and solute diffusion in both liquid and solid phases. To replicate the observed bimodal microstructure, solid–liquid interface properties such as thickness, energy, and mobility were systematically varied to reflect the transition from the shot sleeve to the die cavity. The results demonstrated the model’s ability to capture the growth of dendrites under shot sleeve conditions and nucleation and development of new dendrite arms under the rapid cooling conditions of the die cavity.
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spelling doaj-art-9bb1578e14df408a997eb080979c7af92025-01-24T13:41:34ZengMDPI AGMetals2075-47012025-01-011516610.3390/met15010066Phase-Field Modelling of Bimodal Dendritic Solidification During Al Alloy Die CastingMaryam Torfeh0Zhichao Niu1Hamid Assadi2Brunel Centre for Advanced Solidification Technology Brunel University London, Uxbridge UB8 3PH, UKBrunel Centre for Advanced Solidification Technology Brunel University London, Uxbridge UB8 3PH, UKBrunel Centre for Advanced Solidification Technology Brunel University London, Uxbridge UB8 3PH, UKTracking the microstructural evolution during high-pressure die casting of Al-Si alloys is challenging due to the rapid solidification, varying thermal conditions, and severe turbulence. The process involves a transition from slower cooling in the shot sleeve to rapid cooling in the die cavity, resulting in a bimodal dendritic microstructure and nucleation of new finer dendrite arms on fragmented externally solidified crystals. In this study, a two-dimensional phase-field model was employed to investigate the solidification behaviour of a hypoeutectic Al-7% Si alloy during high-pressure die casting. The model is based on thermodynamic formulations that account for temperature changes due to phase transformation heat, thermal boundary conditions, and solute diffusion in both liquid and solid phases. To replicate the observed bimodal microstructure, solid–liquid interface properties such as thickness, energy, and mobility were systematically varied to reflect the transition from the shot sleeve to the die cavity. The results demonstrated the model’s ability to capture the growth of dendrites under shot sleeve conditions and nucleation and development of new dendrite arms under the rapid cooling conditions of the die cavity.https://www.mdpi.com/2075-4701/15/1/66phase-field modellingHPDCinterface behaviour
spellingShingle Maryam Torfeh
Zhichao Niu
Hamid Assadi
Phase-Field Modelling of Bimodal Dendritic Solidification During Al Alloy Die Casting
Metals
phase-field modelling
HPDC
interface behaviour
title Phase-Field Modelling of Bimodal Dendritic Solidification During Al Alloy Die Casting
title_full Phase-Field Modelling of Bimodal Dendritic Solidification During Al Alloy Die Casting
title_fullStr Phase-Field Modelling of Bimodal Dendritic Solidification During Al Alloy Die Casting
title_full_unstemmed Phase-Field Modelling of Bimodal Dendritic Solidification During Al Alloy Die Casting
title_short Phase-Field Modelling of Bimodal Dendritic Solidification During Al Alloy Die Casting
title_sort phase field modelling of bimodal dendritic solidification during al alloy die casting
topic phase-field modelling
HPDC
interface behaviour
url https://www.mdpi.com/2075-4701/15/1/66
work_keys_str_mv AT maryamtorfeh phasefieldmodellingofbimodaldendriticsolidificationduringalalloydiecasting
AT zhichaoniu phasefieldmodellingofbimodaldendriticsolidificationduringalalloydiecasting
AT hamidassadi phasefieldmodellingofbimodaldendriticsolidificationduringalalloydiecasting