Microstructure and mechanical properties of magnetic levitation fabricated Cu₃₅Ni₃₅Co₃₀ multi-principal element alloy AITranslate

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Chinese Library Classification Number:TG146.1[金属学及工艺—金属材料]

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The urgent need to overcome the strength-ductility trade-off of nickel-aluminum bronze(NAB)in deep-sea engineering motivates the design of a Cu-bearing multi-principal element alloy(MPEA),Cu₃₅Ni₃₅Co₃₀,via magnetic levitation melting.The as-cast Cu₃₅Ni₃₅Co₃₀ MPEA exhibits a dual face-centered cubic(FCC)structure with superior mechanical properties(yield strength:~503 MPa,ultimate tensile strength:~686 MPa,total elongation:~11.0%)over its counterparts fabricated by vacuum arc melting.A single-phase FCC structure was obtained by homogenizing at 1030℃ for 15 h.Cold rolling and postdeformation annealing(PDA)were used to construct heterogeneous grain structures,which were achieved in PDA-treated samples at 1030℃ for 45 s(PDA-1030-45s)and 60 s(PDA-1030-60s).The PDA-1030-45s sample,composed of nano-sized recrystallized grains and residual deformed grains(RDGs),showed the best strength among the PDA-treated samples(a yield strength of~864 MPa,an ultimate tensile strength of~959 MPa,and a total elongation of~13.4%).The PDA-1030-60s sample with micro-sized recrystallized grains and RDGs exhibits an excellent combination of strength and ductility,showing a yield strength of~560 MPa,an ultimate tensile strength of~761 MPa,and a total elongation of~32.9%.These mechanical strengths are superior to those reported by NAB.The dominant strengthening mechanisms of the PDA-1030-45s and the PDA-1030-60s samples are dislocation strengthening and hetero-deformation-induced strengthening,respectively.