Abstract
Processing partially recrystallized microstructure has been proved effective to improve tensile property in high-entropy alloys (HEAs), however, a systematic understanding about the relation among processing parameter, partially recrystallized microstructure and tensile behavior is lacking. Here, five types of recrystallized fractions, 12.5 %, 45.7 %, 77.4 %, 87.0 % and 100 %, were obtained after cold rolling and annealing at 600 °C for 1 h, 3 h, 6 h, 12 h and 120 h in Al0.1CoCrFeNi HEA. All partially recrystallized structures were comprised of non-recrystallized region with strong {111} <112> texture and recrystallized region with a nearly similar scale of fine grain (∼1.22–1.57 μm). The partially recrystallized specimens exhibited a good strength-ductility combination, i.e., yield strength increased from ∼547.1 MPa to ∼881.0 MPa with decreasing recrystallized fractions, while ductility still remained above ∼20 %. Based on the law of mixtures, the calculated results of the contributions from multiple strengthening mechanisms to yield strength closely matched the experimental data. It is found that increasing recrystallized fraction leads to enhancing contribution of grain boundary strengthening but weakening contribution of dislocation strengthening and synergistic strengthening. TEM results revealed that plastic deformation in partially recrystallized specimens was dominated by high-density dislocations and deformation twins in grain interior, as well as dislocation planar slip and pile-up near heterogeneous interface; for comparison, dislocation cells and more deformation twins were formed in fully recrystallized specimens.
Published Version
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