Work

Influence of Sc and Zr on Mg precipitation and sensitization resistance in Al-Mg-(Sc-Zr) alloys

Year: 2025

Type: article

Abstract: Precipitation kinetics of Al3Mg2 in Al-Mg binaries and Al-Mg-Sc-Zr alloys were studied during artificial ageing in the range 170°C-250°C, with the aim to determine the influence of Al3(Sc,Zr) dispersoids on Mg precipitation and resistance to corrosion. A calibration with model alloys enabled a quantitative determination of the evolution of Mg content in solid solution which was coupled with APT measurements performed on samples aged for a long time. Precipitate morphology and distribution were analyzed via SEM and TEM techniques, identifying two phases, β' and β. The β phase is known to form a continuous network of precipitates on grain boundaries, making it sensitive to corrosion. Corrosion tests using nitric acid mass loss on aged samples demonstrated the role of Al3(Sc,Zr) dispersoids in enhancing intergranular corrosion resistance. To illustrate the contribution of different nucleation sites and thus their role in corrosion resistance, the competition between homogeneous and heterogeneous nucleation of Al3Mg2 was modeled based on Classical Nucleation and Growth Theories (CNGTs). Overall, this study, shows that Al3(Sc,Zr) accelerate the precipitation kinetics of Al3Mg2 by lowering the nucleation energy barrier, thereby improving the sensitization resistance of Al-Mg alloys.

Source: Journal of Alloys and Compounds

DOI: 10.1016/j.jallcom.2025.179555

Authors: Maureen Puybras, Véronique Massardier, Damien Fabregue, Michel Perez, Thomas Dorin

Institutions: Centre National de la Recherche Scientifique, Deakin University, Matériaux Ingénierie et Science, Institut National des Sciences Appliquées de Lyon

Language: English

Topic: Aluminum Alloy Microstructure Properties

Subfield: Aerospace Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,660