Engineering

High entropy alloys

Metallurgy

Materials science

Lamellar structure

Chemical engineering

Thermodynamics

Physics

Alloy

Thermal

Microstructure

Eutectic system

Composite material

Casting

Thermal stability

Ingot

Scripta Materialia

Although nanostructured (NS) and ultrafine-microstructure (UFM) materials possess excellent mechanical properties, how to manufacture bulk NS and UFM materials with minimum cost via direct casting remains challenging. Here, we report an efficient strategy to prepare bulk UFM alloys via the direct solidification method for eutectic high-entropy alloy (EHEA). As a proof of concept, we designed CoCrFeNiNb0.45 EHEA and achieved complete bulk UFM ingot with weight of 2.5 kg, demonstrating an ultrafine-lamellar microstructure. The as-cast alloy shows outstanding thermal stability and hardness up to 1100 °C.

Direct solidification of bulk ultrafine-microstructure eutectic high-entropy alloys with outstanding thermal stability