Novel High-Entropy Aluminide-Silicide Alloy

Area of Science:

• Materials Science
• Metallurgy
• Solid State Chemistry

Background:

• High-entropy alloys (HEAs) offer unique properties due to their multi-principal element composition.
• Developing novel HEAs with tailored mechanical and tribological characteristics is crucial for advanced engineering applications.

Purpose of the Study:

• To synthesize and characterize a new equimolar Fe-Al-Si-Ni-Ti high-entropy alloy.
• To evaluate the mechanical properties, including compressive strength and ductility, at room and elevated temperatures.
• To assess the wear resistance and identify wear mechanisms of the developed HEA.

Main Methods:

• Mechanical alloying was employed to produce the alloy powder.
• Spark plasma sintering (SPS) was used for consolidating the alloy powder.
• Compressive strength testing at room temperature and 800 °C was performed.
• Wear resistance was evaluated and compared to tool steel.

Main Results:

• The alloy powder consisted of orthorhombic FeTiSi and B2 FeAl phases.
• Spark plasma sintering led to the formation of FeSi and an increased amount of FeAl phase.
• The material demonstrated high compressive strength (approx. 1500 MPa) at room temperature but was brittle.
• At 800 °C, the alloy exhibited plastic deformability with a yield strength of 459 MPa.
• Excellent wear resistance, comparable to tool steel, was observed, with localized spallation of FeSi particles.

Conclusions:

• The developed Fe-Al-Si-Ni-Ti HEA possesses a unique phase composition after SPS.
• The alloy exhibits a combination of high strength at room temperature and ductility at elevated temperatures.
• Its superior wear resistance makes it a potential candidate for applications requiring high durability.