INVESTIGATION OF THE STRUCTURE OF A NEW ND-RE-AL PHASE USING ELECTRON CRYSTALLOGRAPHY METHODS


Gili Yaniv Louisa Meshi
Department of Materials Engineering and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, Israel

In the framework of the Nd-Re-Al phase diagram study, new ternary phase was discovered with the 2:3:15 stoichiometry. Although alloy of an interest was exposed to prolonged (one month) heat treatment (at 800°C), it did not attained equilibrium state, and contained multiple binary and ternary phases. Therefore, structure solution of the new phase was essentially impossible using traditional X-ray diffraction methods. Electron crystallography, in this case, was the only viable tool applicable for structure solution. Methodology summarized in [1] was successfully applied for characterization of the structure of this aluminide. Classical electron diffraction patterns taken from the particles of this phase exhibited interesting features, attributed to structural defects. Geometry of the unit cell and partial atomic model were deduced applying direct methods (utilized in Sir2014 [2]) on electron diffraction tomography dataset. Structure of the new Nd-Re-Al phase was found to be related to the Ln7+xRe12Al61+y (where Ln = lanthanide element) family [3]. Structural model as well as structure relationship to the Ln7+xRe12Al61+y family will be presented.

References

1. Samuha, Y. Krimer L. Meshi, J. Appl. Cryst. 47 (2014) 1032.

2. C. Burla, R. Caliandro, M. Camalli, B. Carrozzini, G. L. Cascarano, C. Giacovazzo, M. Mallamo, A. Mazzone, G. Polidori, and R. Spagna, J. Appl. Crystallogr. 45 (2012) 357.

3. Niemann, W. Jeitschko, J. Alloys Compd. 221 (1995) 235.

Gili Yaniv
Gili Yaniv
Ben-Gurion University