INFLUENCE OF CU/MN CONTENT AND HOMOGENIZATION REGIMES ON THE MICROSTRUCTURE AND PROPERTIES OF ALTEK ALLOY STRIP

Abstract

This paper presents the results of a comprehensive study on the formation of the microstructure and physical-mechanical properties of strip made from promising aluminum alloys of the ALTEK system (compositions 2Cu1.5Mn and 3Cu2Mn) during a full cycle of thermomechanical processing: cold and hot rolling, annealing. It has been established that the configuration of the particles of the dispersion-strengthening phase Al20Cu2Mn3, which is directly determined by the prior thermal and deformation processing, has a decisive influence on the final set of properties. Prolonged homogenization annealing leads to the formation of large ACrnMn particles (up to 1 pm in size), which are incapable of effectively inhibiting processes of polygonization and recrystallization. In contrast, the omission of homogenization annealing promotes the formation of nano-dispersed Al20Cu2Mn3 particles, characterized by a significantly higher distribution density within the aluminum matrix. The finest plate-shaped particles make the greatest contribution to strengthening and the effective suppression of polygonization and recrystallization processes. The obtained results lead to the conclusion that the homogenization annealing stage is impractical for the basic ALTEK alloys, as this operation leads to a reduction in thermal stability and strength properties.