Crystallite-size distribution and dislocation structure in nanocrystalline HfNi5 determined by x-ray diffraction...

Area of Science:

• Materials Science
• Nanotechnology
• Crystallography

Background:

• Nanocrystalline alloys offer unique properties due to their small grain sizes.
• Melt-spinning is a common technique for producing amorphous and nanocrystalline materials.
• Understanding the microstructure of these alloys is crucial for their application.

Purpose of the Study:

• To synthesize a nanocrystalline Hf11Ni89 alloy via melt-spinning.
• To characterize the crystallite size distribution and dislocation structure of the HfNi5 phase.
• To validate a novel diffraction profile analysis method.

Main Methods:

• Melt-spinning for alloy synthesis.
• X-ray phase analysis for phase identification.
• Advanced diffraction profile analysis for crystallite size and dislocation structure determination.
• Transmission electron microscopy for comparative analysis.

Main Results:

• The as-quenched alloy primarily consists of nanocrystalline face-centered cubic (fcc) HfNi5.
• Median crystallite size was determined to be 3.3 nm with a variance of 0.82.
• Dislocation density was found to be 3.7 x 10^16 m^-2, with dislocations of a nearly pure screw character.
• Results from X-ray analysis showed good agreement with transmission electron microscopy observations.

Conclusions:

• Rapid quenching via melt-spinning effectively produces nanocrystalline Hf11Ni89 alloy.
• The developed diffraction profile analysis method accurately determines crystallite size and dislocation structure.
• The characterized microstructure provides essential data for potential applications of this alloy.