We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Morphology of Spherulites in Rapidly Solidified Ni<sub>3</sub>Ge Droplets.
- Authors
Haque, Nafisul; Cochrane, Robert F.; Mullis, Andrew M.
- Abstract
The congruently melting, single phase, L12 intermetallic β-Ni3Ge has been subject to rapid solidification via drop-tube processing. Four different cooling rates are used in this process, at very low cooling rates (≥850 μm diameter particles, ≥700 K s-1) and slightly higher cooling rates (850-500 μm diameter particles, 700-1386 K s-1) the dominant solidification morphology, revealed after etching, is that of isolated spherulites in an otherwise featureless matrix. At higher cooling rates, (500-300 μm diameter particles, 1386-2790 K s-1 and (300-212 μm diameter particles, 2790-4600 K s-1) mixed spherulite and dendritic morphologies are observed. Indeed, at the higher cooling rate dendrites with side-branches composed of numerous small spherulites are observed. Selected area diffraction analysis in the TEM indicate that the formation of spherulites is due to an order-disorder transformation. Dark-field TEM imaging has confirmed that the spherulites appear to consist of lamellae of the ordered phase, with disordered material in the space between the lamellae. The lamellar width within a given spherulite is constant, but the width is a function of cooling rate, with higher cooling rates giving finer lamellae. As such, there are many parallels with spherulite growth in polymers.
- Subjects
SPHERULITES (Polymers); NICKEL compounds; CRYSTAL growth
- Publication
Crystals (2073-4352), 2017, Vol 7, Issue 4, p100
- ISSN
2073-4352
- Publication type
Article
- DOI
10.3390/cryst7040100