Disorder-order morphologies in drop-tube processed Ni3Ge: Dendritic and seaweed growth

作者：Haque Nafisul^*; Cochrane Robert F; Mullis Andrew M

来源：Journal of Alloys and Compounds, 2017, 707: 327-331.

DOI：10.1016/j.jallcom.2016.11.080

• Intermetallic
• Rapid solidification
• Phase transitions
• Dendrites
• Seaweed structure

The single phase intermetallic beta-Ni3Ge has been subject to rapid solidification via drop-tube processing. Droplets spanning the size range 212-38 mm, with corresponding cooling rates of 5800-54,500 K s(-1), have been subject to microstructural investigation using SEM. Three dominant solidification morphologies have been identified with increasing cooling rate, namely; (i) well-defined dendrites with orthogonal side-branching, (ii) dendrites with non-orthogonal side-branching and (iii) dendritic seaweed. Selected area diffraction analysis in the TEM reveals that both types of dendrites are the disordered form of b-Ni3Ge in a matrix of the ordered, L1(2), form. However, the diffraction pattern from the dendritic seaweed cannot be mapped onto a cubic structure, indicating a change in the underlying crystallography coincident with the transition to the seaweed structure.

• 出版日期2017-6-15