TY - JOUR
T1 - The effect of trace additions of sn on precipitation in Al-Cu alloys
T2 - An atom probe field ion microscopy study
AU - Ringer, S. P.
AU - Hono, K.
AU - Sakurai, T.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 1995/9
Y1 - 1995/9
N2 - We have studied the early stages of θ′ precipitation in an Al-Cu-Sn alloy by atom probe field ion microscopy (APFIM) and transmission electron microscopy (TEM). Clusters of Sn atoms were observed in as-quenched samples, and their formation clearly precedes the formation of the θ′ phase. Transmission electron microscopy also revealed that elevated temperature aging leads to the formation of spherical particles. Atom probe analysis and microbeam electron diffraction suggested that these particles were β-Sn (I41/amd, α = 0.583 nm, and c = 0.318 nm). The TEM observations showed that θ′ nucleated heterogeneously on these particles. We have also examined the θ′/α interface following further precipitate growth to check for possible Sn segregation. Atom probe analysis of both the broad face and the narrow rim of the platelike θ′ precipitates has shown no evidence of Sn segregation at θ′/α interfaces. It was also found that cold work prior to aging inhibits the formation of Sn particles resulting in a lower number of these types of nucleation sites for the θ′ phase. Atom probe analysis has also revealed solute depletion at grain boundaries during the early stages of aging in the Al-Cu-Sn alloy, and this, in conjunction with vacancy depletion, explains the formation of narrow precipitate-free zones observed following further aging.
AB - We have studied the early stages of θ′ precipitation in an Al-Cu-Sn alloy by atom probe field ion microscopy (APFIM) and transmission electron microscopy (TEM). Clusters of Sn atoms were observed in as-quenched samples, and their formation clearly precedes the formation of the θ′ phase. Transmission electron microscopy also revealed that elevated temperature aging leads to the formation of spherical particles. Atom probe analysis and microbeam electron diffraction suggested that these particles were β-Sn (I41/amd, α = 0.583 nm, and c = 0.318 nm). The TEM observations showed that θ′ nucleated heterogeneously on these particles. We have also examined the θ′/α interface following further precipitate growth to check for possible Sn segregation. Atom probe analysis of both the broad face and the narrow rim of the platelike θ′ precipitates has shown no evidence of Sn segregation at θ′/α interfaces. It was also found that cold work prior to aging inhibits the formation of Sn particles resulting in a lower number of these types of nucleation sites for the θ′ phase. Atom probe analysis has also revealed solute depletion at grain boundaries during the early stages of aging in the Al-Cu-Sn alloy, and this, in conjunction with vacancy depletion, explains the formation of narrow precipitate-free zones observed following further aging.
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U2 - 10.1007/BF02671236
DO - 10.1007/BF02671236
M3 - Article
AN - SCOPUS:0029378547
VL - 26
SP - 2207
EP - 2217
JO - Metallurgical Transactions A (Physical Metallurgy and Materials Science)
JF - Metallurgical Transactions A (Physical Metallurgy and Materials Science)
SN - 1073-5623
IS - 9
ER -