Nano-lamellar (L12 + B2) AlCoCrFeNi2.1 eutectic high entropy alloy (EHEA) was processed by cryo-rolling and annealing. The EHEA developed a novel hierarchical microstructure featured by fine lamellar regions consisting of FCC lamellae filled with ultrafine FCC grains (average size ~200–250 nm) and B2 lamellae, and coarse non-lamellar regions consisting of ultrafine FCC (average size ~200–250 nm), few coarse recrystallized FCC grains and rather coarse unrecrystallized B2 phase (~2.5 µm). This complex and hierarchical microstructure originated from differences in strain-partitioning amongst the constituent phases, affecting the driving force for recrystallization. The hierarchical microstructure of the cryo-rolled and annealed material resulted in simultaneous enhancement in strength (Yield Strength/YS: 1437 ± 26 MPa, Ultimate Tensile Strength/UTS: 1562 ± 33 MPa) and ductility (elongation to failure/ef ~ 14 ± 1%) as compared to the as-cast as well as cold-rolled and annealed materials. The present study for the first time demonstrated that cryo-deformation and annealing could be a novel microstructural design strategy for overcoming strength-ductility trade off in multiphase high entropy alloys.

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Simultaneous Strength-Ductility Enhancement of a Nano-Lamellar AlCoCrFeNi2.1 Eutectic High Entropy Alloy by Cryo-Rolling and Annealing

Investigation of orientation gradients around a hard Laves particle in a warm-rolled Fe3Al-based alloy using a 3D EBSD-FIB technique

Environmental embrittlement of iron aluminides

The influence of microstructure on the ductility of iron aluminides

Microstructure and mechanical properties of Fe3Al-based alloys with strengthening boride precipitates

The purpose of the present study was to determine whether recrystallization alone had an effect on the room temperature tensile properties of a Fe[sub 3]Al-based alloy The best room temperature tensile strength and ductility were attained in specimens which had been heat treated to relieve stresses produced by the fabrication process but that had a minimum number of recrystallized grains The exact mechanism for this improvement is unclear, but could involve texturing effects or the enhancement of dislocation mobilities Also the elongated grain structure characteristic of as-rolled material provides a minimum of transverse cleavage planes (as well as a minimum of grain boundaries), and could simply be disrupting the path of atomic hydrogen entering the specimen during tensile stressing

D.H. Pierce

Papers

Effect of recrystallization on room temperature tensile properties of an Fe3Al-based alloy

Evaluation of High-Temperature Martensitic Steels for Heavy-Duty Diesel Piston Applications

Additive manufacturing as a processing route for steel-aluminum bimetallic structures