Solute co-segregation mechanisms at low-angle grain boundaries in magnesium: A combined atomic-scale experimental and modeling study
Published in Acta Materialia, 2026
Solute co-segregation mechanisms at low-angle grain boundaries in magnesium: A combined atomic-scale experimental and modeling study.
Abstract
Solute segregation at low-angle grain boundaries (LAGBs) critically affects the microstructure and mechanical properties of magnesium (Mg) alloys. In modern alloys containing multiple substitutional elements, understanding solute-solute interactions at microstructural defects becomes essential for alloy design. This study investigates the co-segregation mechanisms of calcium (Ca), zinc (Zn), and aluminum (Al) at a LAGB in a dilute Mg-0.23Al-1.00Zn-0.38Ca (AZX010) alloy by combining atomic-scale experimental and modeling techniques. Three-dimensional atom probe tomography (3D-APT) revealed significant segregation of Ca, Zn, and Al at the LAGB, with Ca forming linear segregation patterns along dislocation arrays characteristic of the LAGB. Clustering analysis showed increased Ca–Ca pairs at the boundary, indicating synergistic solute interactions. Atomistic simulations and elastic dipole calculations demonstrated that larger Ca atoms prefer tensile regions around dislocations, while smaller Zn and Al atoms favor compressive areas. These simulations also found that Ca–Ca co-segregation near dislocation cores is energetically more favorable than other solute pairings, explaining the enhanced Ca clustering observed experimentally. Thermodynamic modeling incorporating calculated segregation energies and solute-solute interactions accurately predicted solute concentrations at the LAGB, aligning with experimental data. The findings emphasize the importance of solute interactions at dislocation cores in Mg alloys, offering insights for improving mechanical performance through targeted alloying and grain boundary engineering.
Recommended citation: R. Pei, J. Petrazoller, A. Atila, S. Arnoldi, L. Xiao, X. Liu, H. Wang, S. Korte-Kerzel, S. Berbenni, T. Richeton, J. Guénolé, Z. Xie, T. Al-Samman. "Solute co-segregation mechanisms at low-angle grain boundaries in magnesium: A combined atomic-scale experimental and modeling study." Acta Materialia. (121947).
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Plain Language Summary
🇬🇧 English
This study investigates how different elements (calcium, zinc, and aluminum) interact and cluster together at tiny imperfections, called low-angle grain boundaries, within magnesium alloys. These imperfections are crucial because they significantly influence the metal's overall strength and behavior. Using advanced techniques like atom probe tomography and computer simulations, the researchers observed that calcium atoms tend to gather in specific areas of these boundaries, while zinc and aluminum atoms occupy different spots. This detailed atomic-level understanding is vital for designing stronger and more durable magnesium alloys for various applications, from lightweight vehicles to aerospace components.
🇸🇦 العربية
تدرس هذه الدراسة كيف تتفاعل العناصر المختلفة (الكالسيوم والزنك والألمنيوم) وتتجمع معًا عند العيوب الصغيرة، التي تسمى حدود الحبوب منخفضة الزاوية، داخل سبائك المغنيسيوم. هذه العيوب مهمة لأنها تؤثر بشكل كبير على القوة والسلوك العام للمعدن. باستخدام تقنيات متقدمة مثل التصوير المقطعي الذري بالمسبار والمحاكاة الحاسوبية، لاحظ الباحثون أن ذرات الكالسيوم تميل إلى التجمع في مناطق محددة من هذه الحدود، بينما تشغل ذرات الزنك والألمنيوم أماكن مختلفة. هذا الفهم التفصيلي على المستوى الذري ضروري لتصميم سبائك مغنيسيوم أقوى وأكثر متانة لمختلف التطبيقات، من المركبات خفيفة الوزن إلى مكونات الطيران والفضاء.
🇫🇷 Français
Cette étude examine comment différents éléments (calcium, zinc et aluminium) interagissent et s'agrègent au niveau de minuscules imperfections, appelées joints de grains de faible angle, au sein des alliages de magnésium. Ces imperfections sont cruciales car elles influencent considérablement la résistance globale et le comportement du métal. En utilisant des techniques avancées telles que la tomographie par sonde atomique et des simulations informatiques, les chercheurs ont observé que les atomes de calcium ont tendance à se rassembler dans des zones spécifiques de ces joints, tandis que les atomes de zinc et d'aluminium occupent des endroits différents. Cette compréhension détaillée au niveau atomique est essentielle pour concevoir des alliages de magnésium plus résistants et plus durables pour diverses applications, des véhicules légers aux composants aérospatiaux.
🇩🇪 Deutsch
Diese Studie untersucht, wie verschiedene Elemente (Kalzium, Zink und Aluminium) an winzigen Unvollkommenheiten, sogenannten niedrigwinkeligen Korngrenzen, in Magnesiumlegierungen interagieren und sich dort anreichern. Diese Unvollkommenheiten sind entscheidend, da sie die allgemeine Festigkeit und das Verhalten des Metalls maßgeblich beeinflussen. Mithilfe fortschrittlicher Techniken wie der Atomprobentomographie und Computersimulationen beobachteten die Forscher, dass sich Kalziumatome in bestimmten Bereichen dieser Grenzen ansammeln, während Zink- und Aluminiumatome andere Stellen besetzen. Dieses detaillierte Verständnis auf atomarer Ebene ist entscheidend für die Entwicklung stärkerer und langlebigerer Magnesiumlegierungen für verschiedene Anwendungen, von leichten Fahrzeugen bis hin zu Komponenten in der Luft- und Raumfahrt.