Martensite

Deformation mechanism

Necking

Stacking fault

Dislocation

Condensed matter physics

Composite material

Ductility (Earth science)

Thermodynamics

Ultimate tensile strength

Creep

Grain boundary

Stacking-fault energy

Diffusionless transformation

Microstructure

Metallurgy

Materials science

Work hardening

Alloy

High entropy alloys

Physics

Crystal twinning

Acta Materialia

Tensile properties and deformation mechanisms at 293 and 77 K of single-phase face-centered-cubic (FCC) CrxMn20Fe20Co20Ni40-x (0 ≤ x ≤ 26 at.%) high-entropy alloys (HEAs) with grain sizes (d) in the range [6–283 µm] were studied. A specificity of these alloys is that their stacking fault energy (SFE) strongly decreases with increasing the Cr/Ni ratio while all the other characteristics affecting strength (elastic moduli and solute misfit volumes) remain approximately constant. Therefore, these alloys allow to investigate how the SFE affects the tensile behavior and deformation mechanisms of FCC HEAs. Grain boundary strengthening is found to be nearly independent of SFE, composition, and temperature. While the intrinsic lattice strength (σ0 ≈ 136 MPa) remains approximately constant at 293 K, it strongly increases with increasing Cr/Ni ratio and thus decreasing SFE at 77 K, presumably due to a reduction of dislocation line tension. Deformation twinning occurs at 293 K when x ≥ 20 at.% (SFE ≤ 35 mJ/m2) and in al...

Effects of stacking fault energy and temperature on grain boundary strengthening, intrinsic lattice strength and deformation mechanisms in CrMnFeCoNi high-entropy alloys with different Cr/Ni ratios