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High-Entropy V-Based Null Matrix Alloys─Short/Long-Range Structural Features, Chemical Stabilities, and Mechanical
Man He1,2, Chen Wang1,2,3,4, Hua Yang1,2
1Spallation Neutron Source Science Center, Dongguan, Guangdong 523803, China.
ACS Applied Materials & Interfaces
|April 10, 2025
Summary
Researchers developed novel high-entropy V-based (HEV) alloys, which are null matrix alloys with over five elements. These advanced materials exhibit enhanced resistance and high yield strength, opening new avenues for neutron scattering applications.
Area of Science:
- Materials Science
- Neutron Scattering
- Alloy Development
Background:
- Null matrix alloys, crucial for neutron scattering applications like reaction vessels, traditionally consist of only two elements/isotopes.
- Limited dopant solubility in parent phases historically restricted the modification of null matrix alloy properties.
- Multi-elemental null matrix alloys have not been previously reported due to challenges in achieving desired material properties.
Purpose of the Study:
- To synthesize and characterize a new family of multi-elemental, high-entropy V-based (HEV) alloys.
- To investigate the structural, chemical, and mechanical properties of these novel alloys.
- To establish guidelines for designing complex null matrix materials with tailored characteristics.
Main Methods:
- Two-step arc-melting method for alloy synthesis.
- Neutron diffraction to confirm null matrix characteristics (absence of diffraction peaks).
- Rietveld refinement of high-resolution X-ray diffraction data for structural analysis.
- X-ray pair distribution function (PDF) and small-angle neutron scattering (SANS) to assess atomic ordering and clustering.
- High-temperature oxidation analysis to evaluate material resistance.
Main Results:
- Successfully developed six high-entropy V-based (HEV) alloys, each containing more than five elements.
- All synthesized HEV alloys exhibited no diffraction peaks, confirming their null matrix nature.
- Rietveld refinement indicated homogeneous distribution of dopants within the V-based Im-3m structure.
- PDF and SANS analyses ruled out chemical ordering and clustering.
- HEV alloys demonstrated superior oxidation resistance compared to binary V-based alloys.
- HEV4 alloy exhibited the highest engineering yield strength among the investigated samples.
Conclusions:
- A novel family of multi-elemental high-entropy V-based (HEV) null matrix alloys has been successfully developed.
- These HEV alloys possess unique structural and chemical properties, including homogeneous dopant distribution and enhanced oxidation resistance.
- The findings provide a foundational framework for the design and fabrication of advanced complex null matrix materials for diverse scientific applications, particularly in neutron scattering.
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