Papers by Author: Dong Qiu

Abstract: A minor, but crucial, modification to the original version of the TM was recently proposed in order to ensure that the model predictions were entirely consistent with those of the phenomenological theory of martensite crystallography (PTMC). In the present paper an analysis based on the principles of the Frank-Bilby equation is used to derive this modified version of the two-dimensional TM equation for the habit plane orientation from first principles. A considerably simpler and more accurate expression for the tilt rotation is also presented. Finally, a simple method for using the TM approach to calculate the shape strain, its magnitude and direction is described. The results of the predictions made with this improved version of the TM are compared with those of the original TM and with the corresponding PTMC predictions.

Abstract: Low dimensional nanostructures, e.g. nanowires, self-assembled through heteroepitaxy, present a variety of crystallographic features that do not always follow conventional V-W or S-K growth mode. Applying Δg parallelism rules and edge-to-edge matching (E2EM) model in β-DySi₂/Si and CoSi₂/Si systems provides a better understanding of the natural preference of the interface orientation and the orientation relationship (OR) during heteroepitaxial growth. This may help improving the quality of nanowires through optimizing the substrate orientation.

Abstract: Inoculation is the most common grain refining technique during metal/alloy castings. However, only a small fraction, typically 1~2%, of inoculants serve as nucleation sites while most of them do not participate in the nucleation event and hence they are usually termed ‘inactive’ inoculants. But ‘inactive’ does not mean ‘useless’. Our recent studies revealed some extra merits of these ‘inactive’ particles in Mg-Al-Y cast alloys. The current results represent a new approach to microstructure design through manipulation of inoculated particles during castings.