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Updated: Mar 8, 2026
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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
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Short-range order and atomic dynamics of Ti75Ni25melts
Johanna Wilden1, Dirk Holland-Moritz1, Fan Yang1
1Institute for Frontier Materials on Earth and in Space, German Aerospace Center (DLR), 51147 Köln, Germany.
Summary
Liquid titanium-nickel (Ti75Ni25) exhibits faster atomic dynamics due to less pronounced chemical short-range order compared to other alloys. This structural difference explains the observed differences in atomic mobility and diffusion.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Physical Chemistry
Background:
- Atomic dynamics in liquid alloys are influenced by their structure.
- Ti75Ni25 melts show faster atomic dynamics than Zr64Ni36 and Ni66.7B33.3 melts at similar packing fractions.
Purpose of the Study:
- To investigate the short-range structure of Ti75Ni25 melts.
- To establish a structural explanation for the faster atomic dynamics in Ti75Ni25 melts.
Main Methods:
- Containerless processing using electrostatic levitation under high-purity conditions.
- Determination of partial structure factors via neutron diffraction (with isotopic substitution) and synchrotron X-ray diffraction.
- Analysis using Mode Coupling Theory (MCT) for structure-dynamics relationship.
Main Results:
- Ti75Ni25 melts exhibit chemical short-range order with preferential Ti-Ni nearest neighbors.
- This chemical short-range order is less pronounced than in Zr64Ni36 and Ni66.7B33.3 melts.
- Nickel self-diffusion is slightly faster than titanium self-diffusion (DNi/DTi ≈ 1.2).
- Onsager coefficients from MCT align with Darken's equation, indicating negligible cross-correlation effects in interdiffusion.
Conclusions:
- Less pronounced chemical short-range order in Ti75Ni25 contributes to its faster atomic dynamics.
- The structure-dynamics relationship in liquid Ti75Ni25 is well-described by Mode Coupling Theory.
- Cross-correlation effects are minimal for interdiffusion in liquid Ti75Ni25.
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