J. Phys. Colloques
Volume 48, Numéro C3, Septembre 19874th International Aluminium Lithium Conference
|Page(s)||C3-385 - C3-396|
J. Phys. Colloques 48 (1987) C3-385-C3-396
ATOMIC RESOLUTION IMAGING IN Al-Li-Cu ALLOYV. RADMILOVIC1 et G. THOMAS2
1 University of Belgrade, Department of Physical Metallurgy. Karnegijeva, 4, P.P. 494, Belgrade 11001, Yugoslavia
2 Center for Advanced Materials, Lawrence Berkeley Laboratory, Berkeley, CA 94720 and University of California, Department of Materials Science and Mineral Engineering, Berkeley, CA 94720, U.S.A.
The structure of β'/δ' and T1 precipitates in Al-Li-Cu alloy has been investigated using the atomic resolution electron microscope and computer simulation. Thermal-mechanical processing was done in a program designed to define precipitate nucleation and growth conditions. The results show the β'/δ' complexes are misoriented (1°) L12 ordered particles. The δ' shell develops polygonal facets around β' core. The T1 phase density is considerably increased by mechanical processing between aging treatments and the results are consistent with increased heterogeneous nucleation, especially by slip within δ' particles. The structure of T1 is proposed to be hexagonal with different composition layers ABCDA, but which are faulted during growth.