An analytical electron microscopic investigation of precipitation in an Al-Cu-Zn-Mg-Ag alloy

Journal Article · Mon Mar 01 04:00:00 EST 1993 · Microscopy Research and Technique; (United States)

DOI:https://doi.org/10.1002/jemt.1070240409· OSTI ID:6402413

Hasan, F; Lorimer, G W ^[1]

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1. Univ. of Manchester/UMIST (United Kingdom)

The distribution, morphology, chemistry, and crystallography of the precipitates formed during aging of an Al-Cu-Zn-Mg-Ag alloy have been studied using analytical transmission electron microscopy. The first precipitates to appear during aging at 150 C were thin hexagonal-shaped plate-like precipitates which formed on the (111)[sub Al] planes. These precipitates had a face-centered orthorhombic crystal structure and their composition was essentially CuAl[sub 2] although they contained a trace of silver. At peak hardness the microstructure consisted of the plate-like precipitates on (111)[sub Al] planes and [Theta][prime] precipitates on (100)[sub Al] planes. Overaging resulted in the precipitation of equilibrium [Theta], CuAl[sub 2], which exhibited a lath morphology and an orientation-relationship with the matrix (210)[sub Al] [parallel] (110)[sub [gamma]]; (001)[sub Al] misoriented from (001)[sub [gamma]] by [approximately]6[degree]. Prolonged overaging at 250 C resulted in the formation of cuboid-shaped Al[sub 5](Cu,Zn)[sub 6]Mg[sub 2] precipitates which had a cubic crystal structure and a cube:cube orientation-relationship with the matrix.

• OSTI ID: 6402413
• Journal Information: Microscopy Research and Technique; (United States), Journal Name: Microscopy Research and Technique; (United States) Vol. 24:4; ISSN MRTEEO; ISSN 1059-910X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
CHEMICAL COMPOSITION
COPPER ALLOYS
CRYSTALLOGRAPHY
ELECTRON MICROSCOPY
MERCURY ALLOYS
MICROSCOPY
MOLECULAR STRUCTURE
MORPHOLOGY
PRECIPITATION
SEPARATION PROCESSES
SILVER ALLOYS
TRANSMISSION ELECTRON MICROSCOPY
ZINC ALLOYS