Vacancy Behavior and Solute Cluster Growth During Natural Aging of an Al-Mg-Si Alloy

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 43; no. 12; pp. 4507 - 4513
• Main Authors: Lay, M. D. H., Zurob, H. S., Hutchinson, C. R., Bastow, T. J., Hill, A. J.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.12.2012; Springer; Springer Nature B.V
• Subjects: Aluminum alloys; Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Exact sciences and technology; Materials Science; Metallic Materials; Metallurgy; Metals. Metallurgy; Microstructure; Nanotechnology; Positrons; Structural Materials; Surfaces and Interfaces; Thin Films; Nuclear Magnetic Resonance; Natural Aging; Artificial Aging; Solute Atom; Solute Cluster; Cluster; Aluminium base alloys; Ageing; Magnesium alloy
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-012-1257-7

The natural aging behavior of an Al-0.46Mg-1.05Si-0.14Fe (wt pct) alloy was studied with positron annihilation lifetime spectroscopy at four temperatures and with 25 Mg solid-state nuclear magnetic resonance. The evolution of positron lifetime is shown to consist of three distinct stages. In an effort to understand the physical processes occurring during natural aging, a phenomenological model was developed for the first two stages and is shown to describe the experimental observations well. The description accounts for the decay in positron lifetime due to diffusion of vacancies to sinks and an increase in positron lifetime attributed to growing solute clusters. NMR measurements of 25 Mg solute partitioning during natural aging support the model.