Microsc. Microanal. Microstruct. 4, 265-277 (1993)
DOI: 10.1051/mmm:0199300402-3026500

Behavior of Cu-atoms in formation of G.P. zones and θ' -Phase in Al-Cu Alloys

Hiroshi Fujita et Chin Lu

Research Institute for Science and Technology, Kinki University, Kowakae 3-4-1, Higashi Osaka, Osaka 577, Japan

Abstract
Al-Cu crystals have been investigated by in-situ aging with a high resolution electron microscope. Results obtained are summarized as follows: a) Four types of G.P. zones are formed by aging at low temperatures. b) In these G.P. zones, pre-G.P zones, G.P.-1 and G.P.2(3) whose Cu-rich {100} planes are separated with three Al-rich {100} planes disappear at room temperature by electron irradiation at 300 kV c) G.R-2(2) zones whose Cu-rich {100} planes are separated with two Al-rich {100} planes easily transform to θ'-phase at room temperature by the same electron irradiation. d) The local content of Cu-atoms in these G.P. zones have been estimated from the results obtained by in-situ experiment of electron irradiation induced diffusion. Based on these results, mechanisms on the diffusion of Cu-atoms, the formation of various types of G.P. zones, and the transition from G.P. zones to θ'-phase are discussed in terms of Al-Cu atom pairs.

PACS
6475 - Solubility, segregation, and mixing; phase separation.
6180F - Electron and positron radiation effects.

Key words
Guinier-Preston zones -- Theta phase -- Binary alloys -- Aluminium base alloys -- Copper alloys -- Electron microscopy -- In situ -- Electron beam effects -- Atomic clusters -- Atom migration -- Al Cu


© EDP Sciences 1993