Observations of Pentagonally Twinned Precipitate Needles of Germanium in Aluminum

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Science  22 Aug 1986:
Vol. 233, Issue 4766, pp. 875-876
DOI: 10.1126/science.233.4766.875


Unusual pentagonally twinned precipitates were observed in a high-resolution transmission electron microscopy study of needle-shaped germanium particles in aluminum. Although commonly found in small particles formed on substrates, such twinning has not been seen in precipitates grown in the solid state. The morphologies and orientation relationships are consistent with symmetry principles.