DECOMPOSITION OF CU plus 75% MN SOLID SOLUTION.

Using X-ray analysis methods, structural transformations accompanying the aging of gamma solid solution of cast Cu plus 75 percent Mn at 330-530 degree C for 6 h were studied. gamma phase decomposes into two solid solutions containing 33-35 and 95 percent Mn at a volume fraction of the enriched phase of 65 percent. The DELTA V/at. of the phases reaches 2. 5 percent. The Mn-enriched metastable phase undergoes the FCC-FCT transformation with a decrease of V/at. On powdering of the specimen, that phase acquires the FCC structure and V/at. increases. The volume difference of the phases forming during aging is the source of the internal stresses which have an effect on stability of the metastable structure and damping properties. Improvement of these characteristics can be achieved by alloying. 6 Refs.