The Characteristics of a Metastable 2H Type Phase in a Quenched β1 Cu–Al–Ni Alloy

Publisher Website
Google Scholar
Abstract
A metastable phase in a quenched β1 Cu–14.2Al–4.3Ni (in wt%) alloy has been investigated by means of electron diffraction and electron microscopy. The structure of the metastable phase has been analyzed by a model proposed by Takezawa and Sato for a Cu–Zn alloy, by taking into account the effect of ordering for the present alloy. It has been found that the transformation between the β1 matrix phase and the metastable 2H type phase is reversible and diffusionless in nature. Furthermore, clear evidence has been found that the 2H type phase and the so-called “mottled structure” are present even in the martensitic phase. This is a strong indication that the 2H type phase is not a premartensitic phase but a metastable phase which competes with the subsequent martensitic phase.