Structure and Dynamics of Binary Metallic Melts

Kurzfassung

The short-range structure and the atomic dynamics of melts are of fundamental importance for understanding the solidification behavior of the liquids, including the possible formation of metallic glasses. In this work results of studies on the short-range order and on the atomic dynamics in different stable and undercooled metallic melts are presented. In order to undercool the melts deeply below the melting temperature and to avoid chemical reactions of the melts with crucible materials, the samples are containerlessly processed utilizing the electromagnetic or the electrostatic levitation technique. The short-range structure of the melts is studied by neutron and X-ray diffraction, while the atomic dynamics are investigated by quasielastic neutron scattering (QNS). Full sets of partial structure factors were determined by X-ray and neutron diffraction combined with an isotopic substitution technique for different binary melts of Zr64Ni36,[1] Zr50Ni50 [1], Zr36Ni64 [1], Hf35Ni65 [2], Ni66.7B33.3 [3] and Ti75Ni25 alloys, while Ni(/Ti) and Hf self-diffusion coefficients were measured as a function of temperature by QNS [2,4]. The structural and dynamical properties of the different systems are compared and the relationship between short-range structure and atomic dynamics is discussed within the mode coupling theory of the glass transition. References: [1] B. Nowak, D. Holland-Moritz, F. Yang, Th. Voigtmann, T. Kordel, T.C. Hansen, and A. Meyer, Physical Review Materials, 1, 025603 (2017). [2] B. Nowak, D. Holland-Moritz, F. Yang, Th. Voigtmann, Z. Evenson, T.C. Hansen, and A. Meyer, Phys. Rev. B, 96, 054201 (2017). [3] S. Nell, F. Yang, D. Holland-Moritz, Th. Voigtmann, J. Hu, T.C. Hansen, T. Buslaps, and A. Meyer, PRB 110, 014206 (2024). [4] D. Holland-Moritz, S. Stüber, H. Hartmann, T. Unruh, and A. Meyer, J. Phys. Conf. Ser. 144, 012119 (2009).