Transmission electron microscopic investigation of the β1→β phase transformation in a Mg-Dy-Nd alloy

The phase transformation of β1→β in a Mg-Dy-Nd alloy was studied by TEM. The β1 phase, forming as plates parallel to {11̄00}α, has an f.c.c structure, with a ∼ 0.74 nm, and an orientation relationship that may be described by (11̄1)β1//(112̄0)α, (110)β1//(0001)α. The equilibrium phase β, forming as plates parallel to {11̄00}α, has an ordered f.c.c structure, with a ∼ 2.223 nm, and the orientation relationship between β and the matrix phase is identical to that observed between β1 and matrix phase. Both phases are interconnected according to the orientation relationship: (11̄1)β//(11̄1)β1 and (110)β//(110)β1.