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Amorphization-Densification Coupling Governs Hardness Enhancement in SPS-Consolidated Al-Fe-Nb-(Ni,Ti) Metastable
Nguyen Thi Hoang Oanh1, Nguyen Hoang Viet1
1School of Materials Science and Engineering, Hanoi University of Science and Technology, No 1 Dai Co Viet, Mai, Hanoi 100000, Vietnam.
Materials (Basel, Switzerland)
|June 26, 2026
Summary
Adding nickel (Ni) and titanium (Ti) to aluminum (Al)-rich alloys influences their amorphous structure and hardness. Spark plasma sintering (SPS) optimizes high-strength amorphous-nanocrystalline composites by balancing amorphization and densification.
Area of Science:
- Materials Science and Engineering
- Metallurgy
- Nanotechnology
Background:
- Metastable aluminum (Al)-rich alloys are candidates for high-strength applications.
- Understanding the effects of alloying elements like Nickel (Ni) and Titanium (Ti) on alloy properties is crucial.
- Spark Plasma Sintering (SPS) is a promising technique for consolidating advanced materials.
Purpose of the Study:
- To investigate the combined influence of Ni and Ti on amorphization, SPS behavior, and hardness in Al-Fe-Nb alloys.
- To correlate alloy composition and processing parameters with resulting microstructural evolution and mechanical properties.
- To establish design principles for high-strength Al-based amorphous-nanocrystalline alloys using SPS.
Main Methods:
- Mechanical alloying was employed to synthesize Al-rich Al-Fe-Nb-Ni-Ti alloy powders.
- Spark Plasma Sintering (SPS) was used for consolidation, with displacement analysis to monitor the process.
- Hardness measurements (Vickers hardness) and microstructural analysis (X-ray diffraction, TEM) were performed.
Main Results:
- The quinary alloy (Al82Fe12Nb2Ni2Ti2) exhibited the highest amorphization tendency due to increased configurational entropy and negative mixing enthalpy.
- SPS consolidation at 500 °C yielded amorphous-nanocrystalline composites; higher temperatures (550 °C) promoted devitrification.
- The highest hardness (445.4 HV) was achieved in Al82Fe14Nb2Ni2, indicating hardness is governed by a kinetic balance, not solely amorphization.
Conclusions:
- Hardness in these alloys is controlled by the interplay between amorphous phase retention, fine intermetallic precipitation, and densification efficiency during SPS.
- SPS serves as an effective coupled densification-transformation route for developing high-strength Al-based amorphous-nanocrystalline materials.
- Optimizing alloy composition and SPS parameters is key to tailoring microstructures for desired mechanical performance.
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