Transformations and structures in the Al–Zn–Mg alloy system: A diffraction study using synchrotron radiation and electron precession

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2011-01, Vol.528 (3), p.880-887
• Main Authors: Kverneland, A., Hansen, V., Thorkildsen, G., Larsen, H.B., Pattison, P., Li, X.Z., Gjønnes, J.
• Format: Article
• Language: English
• Subjects: Age-hardening aluminum alloys; Alloy systems; Aluminum base alloys; Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder; Cross-disciplinary physics: materials science; rheology; Diffraction; Electron diffraction; Exact sciences and technology; Materials science; Metastable phases; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Precession; Precipitates; Precipitation; Solid solution, precipitation, and dispersion hardening; aging; Synchrotron radiation; Synchrotron radiation diffraction; Transformation; Transformations; Treatment of materials and its effects on microstructure and properties; X-rays
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2010.10.001

▶ Precession electron- and X-ray synchrotron radiation diffraction study of η′-phase. ▶ Synchrotron X-ray diffraction assess quality of precession electron diffraction data. ▶ Synchrotron X-ray diffraction not applied on η′-phase before. ▶ Unique quality of η′-phase particles; large size and less crystal faults. ▶ Structural transformation description of η′-phase from GP-zones to h-phase. The structure of the hardening η′-phase precipitates in Al–Zn–Mg alloys has been investigated by using precession electron diffraction and X-ray synchrotron radiation diffraction. The latter was recorded as a three-dimensional, continuous intensity distribution from a single alloy grain, from which patterns of remarkable sharpness from the precipitate particles could be extracted. High resolution electron microscopy revealed extensive structural variations with prolific faults in the η′ precipitates. The η′-structures are described in terms of two structure models based on two icosahedral elements that are inherent in the equilibrium η-MgZn2 structure. The role of these icosahedra in the transformations of the alloy system is discussed.