Rev.Adv.Mater.Sci. (RAMS)
No 2, Vol. 25, 2010, pages 128-135

FRAGMENTATION OF THE STRUCTURE IN Al-BASED ALLOYS UPON HIGH SPEED EFFECT

I.G. Brodova, E.V. Shorokhov, A.N. Petrova, I.G. Shirinkina, I.V. Minaev, I.N. Zhgilev and A.V. Abramov

Abstract

Aluminum alloys have high potential as light structural materials. In this work light and electron microscopy and X-ray diffraction were used to study the structure and phase composition of deformed bulk samples from the Al-7075 and the Al-3003 alloys. Severe plastic deformation was carried out by the dynamic channel angular pressing (DCAP). In this method the rate of deforming materials is estimated to 103-105 s-1. The finite element method was used to model the deformation process for samples when they moved through intersecting channels. Optimal process parameters to form the uniform structure in the samples were determined. The resulting data of this studying indicate that the formation of ultrafine-grain (UFG) structure is result from two mechanisms - a fragmentation in multicomponent Al alloys (Al-7075) and dynamic recrystallisation in low-alloyed alloys (Al-3003). Such different structure formation demonstrates a realization of two channels of elastic energy relaxation. Thus, DCAP method can be applied effectively for production UFG (~200-500 nm) bulk samples from industrial aluminum alloys with high hardness values (in 1.5 times higher than initial state) and high plasticity.

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