Role of small addition of Sc and Zr in clustering and precipitation phenomena induced in AA7075

0538139 - ÚFP 2021 RIV CH eng J - Článek v odborném periodiku
Vlach, M. - Kodetová, V. - Čížek, J. - Leibner, M. - Kekule, T. - Lukáč, František - Cieslar, M. - Bajtošová, L. - Kudrnová, H. - Šíma, V. - Zikmund, S. - Černošková, E. - Kutálek, P. - Neubert, V.-D. - Neubert, V.
Role of small addition of Sc and Zr in clustering and precipitation phenomena induced in AA7075.
Metals. Roč. 11, č. 1 (2021), s. 1-21, č. článku 8. E-ISSN 2075-4701
Institucionální podpora: RVO:61389021
Klíčová slova: 7xxx aluminum series * Activation energy * Al3(Sc,Zr) particles * Annihilation of positrons * Corrosion * Early precipitation stages
Obor OECD: Materials engineering
Impakt faktor: 2.695, rok: 2021
Způsob publikování: Open access
https://www.mdpi.com/2075-4701/11/1/8

A detailed characterization of phase transformations in the heat-treated commercial 7075 aluminum alloys without/with low Sc–Zr addition was carried out. Mechanical and electrical properties, thermal and corrosion behavior were compared to the microstructure development. The eutectic phase consists of four parts: MgZn2 phase, Al2CuMg phase (S-phase), Al2Zn3Mg3 phase (Tphase), and primary λ-Al(Mn,Fe,Si) phase. Strengthening during non-isothermal (isochronal) annealing is caused by a combination of formation of the GP zones, η’-phase, T-phase and co-presence of the primary and secondary Al3(Sc,Zr)-phase particles. Positive influence on corrosion properties is owing to the addition of Sc–Zr. Positron annihilation showed an evolution of solute Zn,Mg-(co)clusters into (precursors of) the GP zones in the course of natural ageing. The concentration of the (co-)clusters is slightly negatively affected by the low Sc–Zr addition. A combination of both precipitation sequences of the Al–Zn–Mg–Cu-based system was observed. The apparent activation energy values for dissolution/formation of the clusters/GP zones and for formation of the metastable η’-phase, stable T-phase and stable η-phase were calculated.
Trvalý link: http://hdl.handle.net/11104/0315961