The crystallography of cleavage fracture in Al sub 3 Sc
- Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany, F.R.). Inst. fuer Werkstoffwissenschaften
- Oak Ridge National Lab., TN (USA)
The intermetallic compound Al{sub 3}Sc is a trialuminide with the Ll{sub 2} structure, which deforms easily in compression at room temperature, with yield stresses around 100 MPa. In tension Al{sub 3}Sc fractures transgranularly in a brittle manner. The predominant cleavage plane is (011). Regions, which are flat within experimental resolution are only occasionally observed. Numerous cleavage steps, which are aligned in 3 major crystallographic directions, are found. Some of these steps consist of (111) or (001) planes, but others are not distinctly crystallographic. Plastic deformation involving dislocation motion or twinning may have occurred at some of these steps. Reactions between different types of steps are also observed. One type of cleavage patterns found is strikingly similar to the typical appearance of fracture surfaces of fcc brass and Cu{sub 3}Au after stress corrosion cracking. However, this particular pattern is only rarely observed in Al{sub 3}SC. Our observations indicate that an interpretation of cleavage fracture in Al{sub 3}Sc in terms of surface energies alone is unlikely to be successful. A full understanding of the fracture morphology of Al{sub 3}Sc will require detailed atomistic simulations taking dislocation motion and twinning into account. 11 refs., 6 figs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- Sponsoring Organization:
- DOE/ER
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6486989
- Report Number(s):
- CONF-901105-22; ON: DE91004380
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM COMPOUNDS
CHEMICAL REACTIONS
CLEAVAGE
CORROSION
CRACKING
CRYSTAL STRUCTURE
CRYSTALLOGRAPHY
DECOMPOSITION
DEFORMATION
ELECTRON MICROSCOPY
FRACTURE PROPERTIES
INTERMETALLIC COMPOUNDS
MECHANICAL PROPERTIES
MICROSCOPY
MICROSTRUCTURE
PYROLYSIS
SCANDIUM COMPOUNDS
SCANNING ELECTRON MICROSCOPY
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS