Berlin 2008 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 23: Poster session

MM 23.29: Poster

Tuesday, February 26, 2008, 14:45–18:00, Poster B

The Grain Refinement in a Commercial Al-Mg-Sc-Zr Alloy during Hot ECAP and Subsequent Isothermal Rolling — •Olga Sukhopar¹, Oleg Sitdikov^2,3, Günter Gottstein¹, and Rustam Kaibyshev⁴ — ¹Institute of Physical Metallurgy and Metal Physics, RWTH, Aachen 52074, Germany — ²Institute for Metals Superplasticity Problems, Ufa 450001, Russia — ³Department of Engineering Physics, Electronics and Technology, Nagoya Institute of Technology, Nagoya 466-855, Japan — ⁴Belgorod State University, Belgorod 308034, Russia

Grain refinement taking place in a commercial Al-Mg-Sc-Zr alloy under equal channel angular pressing (ECAP) and subsequent isothermal rolling, which were carried out at a temperature of 325°C, was examined. With increase of strain the initial grains were highly elongated along the extrusion direction, and new fine grains formed along initial boundaries composing mantle region. Then new grains with size ~ 1.5 μm were evolved in the grain interiors. During subsequent rolling the fraction of recrystallized grains increases. However, even after highest strains attained no full recrystallized structure was observed. Texture measurements have shown a randomly oriented structure. These results suggest that the dynamic evolution of new grains can be result from (sub)grains rotation, which leads to a rapid increase in misorientation of grain boundaries and to texture randomization. It was shown that progressive increase of misorientation of deformation induced boundaries (continuous dynamic recrystallization) is the main mechanism of submicrocrystalline grain formation.