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MM: Fachverband Metall- und Materialphysik

MM 7: Microstructure and Phase Transformations II

MM 7.4: Vortrag

Montag, 16. März 2015, 12:30–12:45, H 0106

Coherency and coarsening behavior of Al3(Sc,Zr) precipitation in aluminum alloys subjected to severe plastic deformation — •Vladislav Kulitckii¹, Sergey Malopheyev¹, Rustam Kaibyshev¹, Sergiy Divinski², and Gerhard Wilde² — ¹Laboratory of Mechanical Properties of Nanoscale Materials and Superalloys, Belgorod State University, Pobeda 85, Belgorod 308015, Russia — ²Institute of Materials Physics, University of Münster, Wilhelm-Klemm-Str. 10 Münster, Germany

The coarsening behavior of the Al3(Sc,Zr) particles in Al-5.4Mg-0.4Mn-0.2Sc-0.09Zr (alloy 1) and Al-4.6Mg-0.35Mn-0.2Sc-0.09Zr (alloy 2) alloys was investigated using transmission electron microscopy (TEM). The alloys were subjected to equal channel angular pressing (ECAP) in the temperature range of 300-450°C and up a to total strain of ε~12. In the initial state, homogeneously distributed round nanoscale Al3(Sc,Zr) precipitates with average size ~9 nm were observed. Some of these particles featured a characteristic coffee-bean contrast, reflecting their coherence with the matrix. The severe plastic deformation of alloy 1 does not lead to significant coarsening of the Al3(Sc,Zr) particles, their average size was ~11 nm after ECAP at 300, 350, 400 and 450°C. Moreover, the coffee-bean TEM contrast was retained indicating the coherence between particles and matrix. In alloy 2, the Al3(Sc,Zr) precipitates demonstrated a different behavior. After deformation at 300-450°C, no significant change of the size of these precipitates was observed; however, some fraction of the particles lost their coffee-bean contrast and appeared as black circles.