Current positron studies of structural modifications in age-hardenable metallic systems

• Published in: Journal of physics. Condensed matter Vol. 10; no. 46; pp. 10409 - 10422
• Main Authors: Dupasquier, A, Folegati, P, Diego, N de, Somoza, A
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Bristol IOP Publishing 23.11.1998; Institute of Physics
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Metals. Metallurgy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other interactions of matter with particles and radiation; Physics; Positron annihilation; Solid solution hardening, precipitation hardening, and dispersion hardening; aging; Solid solution, precipitation, and dispersion hardening; aging; Treatment of materials and its effects on microstructure and properties; Precipitation; Reviews; Vacancies; Phase transformations; Alloys; Positron annihilation; Defect structure; Microstructure; Age hardening
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/10/46/009

The sensitivity of positron annihilation characteristics to the structural changes occurring in supersaturated metallic systems has been demonstrated and explained since the early 1980s. This knowledge is currently applied for positron annihilation spectroscopy (PAS) investigations regarding the main phenomena that govern the structural evolution of a supersaturated alloy when various thermal treatments are applied: (a) kinetics of vacancy-type defects retained after quenching; (b) solute migration; (c) formation of solute clusters and/or GP zones; (d) precipitation. The analysis of PAS data gives information on the chemical composition, the defect structure and the density of decomposition products of nanometric size. The present article, that includes an exhaustive repertory of works published since 1987, discusses the value of the contribution that PAS studies can give to physical metallurgy in the field of age-hardenable systems. Most examples are taken from the direct experience of the authors. Materials discussed: a variety of aluminum alloys.