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Title: Investigation of Copper Segregation to the S5(310)/[001] Symmetric Tilt Grain Boundary (STGB) in Aluminum

Conference ·
OSTI ID:791396

The {Sigma}5 (310)/[001] symmetric tilt grain boundary (STGB) in the face centered cubic (FCC) metal aluminum with 1at% copper has been studied. The model grain boundary has been fabricated by ultra-high vacuum diffusion bonding of alloy single crystals. The segregation of the copper has been encouraged by annealing the sample after bonding at 200 C. TEM samples of this FCC-material were prepared with a new low voltage ion mill under very low angles. The atomic structure of the {Sigma}5 (310)/[001] STGB for this system was modeled with electronic structure calculations. These theoretical calculations of this interface structure indicate that the Cu atoms segregate to distinct sites at the interface. High resolution electron microscopy (HRTEM) and analytical electron microscopy including electron energy spectroscopic imaging and X-ray energy dispersive spectrometry have been used to explore the segregation to the grain boundary. The HRTEM images and the analytical measurements were performed using different kinds of microscopes, including a Philips CM300 FEG equipped with an imaging energy filter. The amount of the segregated species at the interface was quantified in a preliminary way. To determine the atomic positions of the segregated atoms at the interface, HRTEM coupled with image simulation and a first attempt of a holographic reconstruction from a through-focal series have been used.

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE Office of Defense Programs (DP) (US)
DOE Contract Number:
W-7405-Eng-48
OSTI ID:
791396
Report Number(s):
UCRL-JC-136470; TRN: US200206%%35
Resource Relation:
Conference: 1999 Materials Research Society Fall Meeting, Boston, MA (US), 11/29/1999--12/03/1999; Other Information: PBD: 15 Nov 1999
Country of Publication:
United States
Language:
English