Аннотация:The π phase of Mn-Al and Mn-Al-Ti alloys, wich appears in the process of the isothermal transformation of the quenched ε phase to the stable phases (i.e. ζ and β-Mn), has been experimentally investigated and the T.T.T. diagrams of the alloys with various compositions have been determined. Details of the isothermal transformation were found to depend on the alloy compositions as shown below:(This article is not displayable. Please see full text pdf.) \ oindentThus, an alloy consisting of the π phase alone can be obtained by the isothermal transformation (I) when the Mn-content is less than 56 at% in Mn-Al alloys or 55 at% in Mn-Al-2.7 at%Ti alloys. In alloys with more than 3.5 at%Ti, the ferromagnetic phase is π′ (bcc, a=3.14 Å).