Mechanistic understanding of Mg17Al12 mediated microstructural refinement and strengthening in Mg-Al Alloys – a comprehensive review
5 affiliations
- 1Department of Metallurgical and Materials Engineering, Faculty of Chemical, Metallurgical & Polymer Engineering, University of Engineering & Technology (UET), Lahore, Pakistan
- 2School of Engineering, University of Leicester, Leicester LE1 7RH, UK
- 3Department of Mechanical Engineering, Incheon National University, Incheon 22012, Republic of Korea
- 4School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China
- 5School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
Abstract
This review presents an in-depth mechanistic analysis of the microstructural refinement and strengthening pathways in Mg-Al alloys, with a focus on the influence of Mg 17 Al 12 precipitates. The Hall-Petch relationship, with a slope exceeding 150 MPa·µm 1/2 in most AZ-series Mg alloys, underscores the pivotal role of grain size in dictating yield strength. This high sensitivity to grain size is particularly affected by Al content and crystallographic texture of Mg alloys. This necessitates sophisticated thermomechanical treatments such as severe plastic deformation, twin-induced recrystallization, and rapid solidification for effective grain refinement. The Mg 17 Al 12 phase, characterized by its discontinuous or interconnected morphology in as-cast alloys (e.g., AZ80, AZ91), exerts a strong influence on ductility and fracture resistance. Controlled heat treatments enable modulation of Mg 17 Al 12 morphology, volume fraction, and crystallographic orientation, transitioning from coarse, brittle eutectics to fine, dispersed precipitates with semi-coherent interfaces. These changes fundamentally alter stress accommodation and interaction with dislocations, impacting both precipitation hardening and grain boundary strengthening. However, limited age hardening arises from sluggish solute diffusion and modest precipitation strengthening in the Mg matrix, imposing constraints on high-temperature performance. The review critically evaluates orientation relationships between Mg 17 Al 12 and the α-Mg matrix, detailing their effect on interfacial energies, nucleation sites, and deformation mechanisms. Recent advances in microalloying, process design, and hierarchical microstructure control are discussed to optimize the strength-ductility synergy for automotive applications. Proposed strategies integrate advanced grain refinement, targeted precipitate engineering, and alignment of Mg 17 Al 12 precipitates to achieve application-specific mechanical performance in Mg-Al alloys.
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BibTeX
@article{zubair2026mechanistic,
title = {{Mechanistic understanding of Mg17Al12 mediated microstructural refinement and strengthening in Mg-Al Alloys – a comprehensive review}},
author = {Muhammad Zubair and Umer Masood Chaudry and Khushnuda Nur and Hafiz Muhammad Rehan Tariq and Abdul Malik and Muhammad Asif Rafiq and Mansoor Ali},
journal = {Journal of Magnesium and Alloys},
year = {2026},
month = may,
doi = {10.1016/j.jma.2026.102139},
url = {https://doi.org/10.1016/j.jma.2026.102139},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Mechanistic understanding of Mg17Al12 mediated microstructural refinement and strengthening in Mg-Al Alloys – a comprehensive review
AU - Muhammad Zubair
AU - Umer Masood Chaudry
AU - Khushnuda Nur
AU - Hafiz Muhammad Rehan Tariq
AU - Abdul Malik
AU - Muhammad Asif Rafiq
AU - Mansoor Ali
PY - 2026
DA - 2026/05/28
JO - Journal of Magnesium and Alloys
DO - 10.1016/j.jma.2026.102139
UR - https://doi.org/10.1016/j.jma.2026.102139
AB - This review presents an in-depth mechanistic analysis of the microstructural refinement and strengthening pathways in Mg-Al alloys, with a focus on the influence of Mg 17 Al 12 precipitates. The Hall-Petch relationship, with a slope exceeding 150 MPa·µm 1/2 in most AZ-series Mg alloys, underscores the pivotal role of grain size in dictating yield strength. This high sensitivity to grain size is particularly affected by Al content and crystallographic texture of Mg alloys. This necessitates sophisticated thermomechanical treatments such as severe plastic deformation, twin-induced recrystallization, and rapid solidification for effective grain refinement. The Mg 17 Al 12 phase, characterized by its discontinuous or interconnected morphology in as-cast alloys (e.g., AZ80, AZ91), exerts a strong influence on ductility and fracture resistance. Controlled heat treatments enable modulation of Mg 17 Al 12 morphology, volume fraction, and crystallographic orientation, transitioning from coarse, brittle eutectics to fine, dispersed precipitates with semi-coherent interfaces. These changes fundamentally alter stress accommodation and interaction with dislocations, impacting both precipitation hardening and grain boundary strengthening. However, limited age hardening arises from sluggish solute diffusion and modest precipitation strengthening in the Mg matrix, imposing constraints on high-temperature performance. The review critically evaluates orientation relationships between Mg 17 Al 12 and the α-Mg matrix, detailing their effect on interfacial energies, nucleation sites, and deformation mechanisms. Recent advances in microalloying, process design, and hierarchical microstructure control are discussed to optimize the strength-ductility synergy for automotive applications. Proposed strategies integrate advanced grain refinement, targeted precipitate engineering, and alignment of Mg 17 Al 12 precipitates to achieve application-specific mechanical performance in Mg-Al alloys.
SN - 2213-9567
ER -