Characteristic features of the formation of metastable structures in alloys of the Mn?Cu system

Abstract

1. When Mn−Cu alloys contain more than 55% of Mn, pronounced heterogenizing of the solid solution, which results in the formation of metastable segregations of almost pure copper for a short homogenizing time, occurs during cooling from the homogeneous γ-region. 2. Heterogenizing of the solid solution during cooling is governed by the presence of a high-temperature β-region not only in alloys with an Mn content higher than 55%, but also in an alloy with 55% of Mn and low copper solubility in the β-modification of the manganese. 3. The difference in the decomposition kinetics of the solid solution in alloys with a different manganese content is governed not by a change in the decomposition mechanism on conversion from an alloy with 45% Mn to alloys with a high Mn content, but by the occurrence of two concurrent processes in alloys containing more than 45% of Mn: manganese enrichment of manganese-impoverished regions during cooling from the temperature of the heat in quenching to values below the solubility limit in the γ-solid solution, and the lamination process of the matrix solid solution with the formation manganese-enriched and-impoverished regions.