Multiple twins of {tau}{sup 2}-Al{sub 13}Co{sub 4} showing fivefold symmetry
- Dalian Univ. of Technology (China). Dept. of Materials Engineering
The presence of a monoclinic {tau}{sup 2}-Al{sub 13}Co{sub 4} phase, whose a and c are about {tau}{sup 2} = 2.618 ({tau} = (1 + {radical} 5)/2) times greater than the respective parameters of the monoclinic Al{sub 13}Co{sub 4}, and its (100) and (001) twins has been reported earlier. Like its prototype structure, the monoclinic Al{sub 13}Fe{sub 4}/Al{sub 13}Co{sub 4}, this {tau}{sup 2}-Al{sub 13}Co{sub 4} also shows a tendency to form multiple twins displaying five-fold symmetry. A transmission electron microscopic study of the twin mechanisms has been carried out. In addition to the well-known (001) and (100) glide twins, (20-1) glide twins have also been found. Alternate (100)-(20-1) or (100)-(001)-(100) twinning will yield twins displaying, five-fold symmetry. The distribution of Co atoms in the pentagonal layer in {tau}{sup 2}-Al{sub 13}Co{sub 4} and the tessellation of pentagons in the tessellation of pentagons in the (100) and (20-1) glide twins have also been studied by high-resolution electron microscopy.
- OSTI ID:
- 42851
- Journal Information:
- Metallurgical Transactions, A, Vol. 26, Issue 4; Other Information: PBD: Apr 1995
- Country of Publication:
- United States
- Language:
- English
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