Structural changes of the Cu-0.6Cr alloy upon cooling at different rates after a large high-temperature deformation

The present work studies changes in the structure of samples of the Cu-0.6Cr alloy in the state of a supersaturated solid solution, subjected to large plastic deformation by upsetting by 90% (e ≈ 2.0) at a temperature of 800°С and cooling in various environments: liquid nitrogen, water and air, providing different cooling rates of the material. It is shown that the cooling rate has a decisive influence on the type of structure formed. It was found that in the Cu-0.6Cr alloy, a decrease in the cooling rate leads to a decrease in the fraction of high-angle boundaries and to the formation of a finer structure at the meso and micro levels. At the same time, strength and conductivity values grow. At a high cooling rate (liquid nitrogen), the structural state corresponding to the stage of dynamic recrystallization and polygonization is observed. Such a structure has a low dislocation density and more perfect boundaries. When cooling in air at the first stage, post-dynamic recrystallization processes develop, associated with the nucleation of new nuclei of recrystallized grains along the boundaries of deformed grains, as well as the development of a substructure. The average grain and subgrain size decreases to 1.7± 0.2 and 1.1± 0.2 μm, respectively. With further cooling, from a temperature of ≈600°С, two competing processes that develop during aging obviously begin to occur, namely, the recovery of the structure and the decomposition of the solid solution. This is evidenced from a decrease in the lattice parameter and an increase in electrical conductivity (up to 79% IACS), and the close interaction of dispersed particles 5-10 nm in size and dislocations leads to the further development of the substructure. At the same time, the proportion of middle-angle boundaries increases and the proportion of twin boundaries decreases, while the proportion of high-angle boundaries of the general type remains practically unchanged.

Effect of deformation temperature on grain refinement in alpha titanium alloy VT5-1

M.A. Murzinova

Abnormal effect of strain rate on dynamic recrystallization of austenite in medium carbon steel alloyed by boron

T.V. Kniaziuk, A.A. Zisman

The effect of temperature and strain rate on tensile behaviour of the Mg-2Zn-0.1Ca alloy

D.L. Merson, I.S. Yasnikov, A.I. Brilevsky, M.L. Linderov, A.V. Danyuk, E.D. Merson

1. Russian Science Foundation - №19-19-00432