Relationship between structure and dynamics in liquid Al1-xNix alloys

Area of Science:

• Materials Science
• Physical Chemistry
• Computational Materials Science

Background:

• Understanding the behavior of liquid alloys is crucial for materials processing and applications.
• Aluminum-Nickel (Al-Ni) alloys exhibit complex structural and dynamic properties that are not fully understood.
• Previous studies often focused on specific compositions or temperature ranges.

Purpose of the Study:

• To investigate the structural and dynamic properties of liquid Al-Ni alloys across a range of compositions.
• To elucidate the relationship between chemical short-range order (CSRO) and icosahedral short-range order (ISRO).
• To analyze the composition dependence of transport properties, including diffusion coefficients.

Main Methods:

• Ab initio molecular dynamics (AIMD) simulations were employed.
• Analysis of partial pair-correlation functions and Bhatia-Thornton structure factors.
• Three-dimensional pair-analysis techniques were utilized to examine short-range order.

Main Results:

• A non-linear composition dependence of chemical short-range order (CSRO) was observed.
• A strong interplay between icosahedral short-range order (ISRO) and CSRO was identified in Ni-rich compositions.
• Transport properties, such as self-diffusion and inter-diffusion coefficients, showed non-linear evolution with composition, correlating with structural changes.

Conclusions:

• The structural and dynamic properties of liquid Al-Ni alloys are strongly composition-dependent.
• Icosahedral short-range order plays a significant role in the chemical ordering of Ni-rich Al-Ni alloys.
• AIMD simulations provide valuable insights into the complex behavior of liquid alloys.