Structural Analysis of Dispersion Strengthened Material on Aluminium Base

Abstract

Dispersion strengthened materials are characterized by high strength properties and good temperature stability of structure until to temperatures of 0.9 melting temperature of aluminium. Dispersion strengthened Al-Al4C3materials are prepared by powder metallurgy way and the raw powder mixtures are generally consolidated by hot extrusion obtaining a fully dense material. This work is focused on a study of the microstructure in AI-AI4C3materials containing 4 and 12 vol. % Al4C3. The microstructure was analyzed by transmission electron microscopy and X-ray diffraction methods. The several microstructural features: morphology, size and distribution of particles of dispersoid, grain size and crystallite size of aluminium matrix, micro strain and dislocations density in materials were determined. The aim is an analysis of the effect of Al4C3 amount on the microstructure formation during hot extrusion and analysis of the microstructure evolution at temperature loading and after cooling to ambient temperature. After hot extrusion the Al-12 vol. % Al4C3alloy is characterized by finer grains, higher micro strain and dislocations density and by a very low intensity of aluminium matrix deformation texture in comparison to Al-4 vol. % Al4C3material. In the hot extruded system with 4 vol. % AI4C3a strong deformation texture was observed. Therefore the amount of dispersoid strongly affects the formation of microstructures. The higher volume of Al4C3 particles provides effective hindrance of the dislocations motion in AI matrix by the attractive interaction between dislocations and particles during extrusion. Both amounta of Al4C3dispersoid insure the thermal stability of microstructure of analyzed materials to 773 K. © 2011, Walter de Gruyter GmbH & Co. All rights reserved.