The bcc-to-fcc phase transformation during dezincification of β-phase Cu-Zn

TROIANI; PELEGRINA; AHLERS

PHILOSOPHICAL MAGAZINE A

Taylor and Francis

Año: 1998 p. 1253 - 1267

0141-8610

β-phase Cu-48at% Zn single-crystal slices with (100)β and (110)p surface orientations have been dezincified in vacuum at 450 and 600°C for various times, and the resulting surfaces have been studied by optical microscopy, and also by scanning and transmission electron microscopy. On dezincification, the β phase becomes unstable and two different competing nucleation processes occur, one being a coherent homogeneous nucleation within the β-phase matrix of a non-equilibrium 4H type of hexagonal structure, and the other a heterogeneous formation of long straight needles of the fcc α phase, with an interface orientation given by (211)β parallel to (121)α and a parallelism of the close packed directions [011]β and [111]α within the planes.