Microstructure Evolution and Mechanical Properties of Dual-Phase AlCrFe2Ni2 High-Entropy Alloy Under High-Strain-Rate Compression

This paper investigates the effect of strain rate on the mechanical deformation and microstructural development of dual-phase AlCrFe₂Ni₂ high-entropy alloy during quasi-static and dynamic compression processes. It is revealed that the as-cast AlCrFe₂Ni₂ alloy is composed of a mixture of FCC, disordered BCC, and ordered B2 crystal structure phases. The alloy shows excellent compressive properties under quasi-static and dynamic deformation. The yield strength exceeds 600 MPa while the compressive strength is more than 3000 MPa at the compression rates of 30% under quasi-static conditions. Under dynamic compression conditions, the ultimate compression stresses are 1522 MPa, 1816 MPa, and 1925 MPa with compression strains about 12.8%, 14.7%, and 18.2% at strain rates of 1300 s^-1, 1700 s^-1 and 2100 s^-1, respectively. The dynamic yield strength is approximately linear with strain rate within the specified range and exhibit great sensitivity. The strong localized deformation regions (i.e., adiabatic shear bands (ASBs)) appear in dynamically deformed samples by dynamic recrystallization due to the conflicting processes of strain rate hardening and heat softening.