On the η′ precipitate phase in 7050 aluminium alloy

Abstract

The η′ precipitate phase in 7050 aluminium alloy has been investigated by means of transmission electron microscopy and dynamical diffraction simulation. It is found that the η′ phase has a ⊂-face-centered orthorhombic crystal structure with a=0.492 nm, b=0.852 nm, c=0.701 nm. The orientation relationship between the η′ phase and the matrix is [1 1 −2] m //[1 0 0] η′ , [1 −1 0] m //[0 1 0] η′ , [−1 −1 −1] m //[0 0 1] η′ . A crystal structure model of the η′ phase has been developed and validated by means of dynamical diffraction simulation.