Transformation Process of β-phase of Cu-Al System and the Effect of Mn Addition upon it. (Report No.5)

On the Relationship among the Metastable Phases and their Crystal Structures

Abstract

In this paper is described the atom arangement of the supercooled structures of β-phase, named β₁ β' and γ'. and the relationship among these metastable phases. The β-phase crystallizes in a body centered cubic lattice, disordered; β₁ a body centered cubic, ordered; and γ' a hexagonal close-packed. β' can transform to γ' by mechanical deformation and comes near to γ' with the addition of Mn. It is reasonable that the crystal structure of β' does not strikingly differ from that of γ', so the author supports the opinion that β' crystal is destorted a bit from γ'. With addition of Mn β is supercooled easily to the room temperature. This β₁ transforms to γ' by mechanical deformation.