ISSN:
1573-2746
Keywords:
grain boundary
;
atomic structure
;
high-resolution images
;
Al-5% Mg alloy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract A symmetrical tilt Σ=5[001]/(310) grain-boundary and its surrounding matrix in an Al-5% Mg alloy, as prepared by cold rolling and annealing, have been studied by conventional transmission electron microscopy, high-resolution electron microscopy, and analytical electron microscopy. EDS measurements of the Mg concentration in the bulk and at grain boundaries indicate variations of Mg content ranging between 4 to 11 atomic percent. This variation is attributed to local ordering of Mg atoms in the alloy. HREM images show that the boundary runs parallel to the median of (310) and contains segments primarily composed of two types of structural unit. One unit contains seven atomic sites, while the other contains eight. In both types of unit, the grain-boundary coincident site lattice is continuous across the interface and exhibits periodicity in its core structure. The core structure, which is characterized by “kite-like” structural units containing seven atoms, conforms well with the structure of Σ=5 grain boundaries in pure FCC materials. The presence of atomic-scale ordering of Mg atoms along [001] of the boundary core is associated with the existence of the structural unit possessing eight atomic sites.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00191050
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