Effects of cold rolling and heat treatment on microstructure and mechanical properties of(FeCoNiCr)100-x-yAlxTiy high-entropy alloy
The(FeCoNiCr)100-x-yAlxTiy high-entropy alloy was prepared using a vacuum induction lev-itation melting furnace,and the(FeCoNiCr)93Al5Ti2 was cold-rolled and heat-treated.The microstructure of the alloy was analyzed using scanning electron microscopy(SEM),electron backscatter diffraction(EBSD),and X-ray diffraction(XRD).The results showed that the alloy is face centered cubic(FCC)in both cast and annealed phases.(FeCoNiCr)93Al5Ti2 alloy after cold rolled 50％and heat treatment,the grain size is signifi-cantly refined,and a large number of annealing twins are formed in the crystal,massive micron L12 phase at the boundary,and nanoscale L12 phase in the grain.Compared to the as cast FeCoNiCr alloy,the yield strength increased from 145 MPa to 481 MPa,an increase of 231.7％;The tensile strength increased by 91.0％from 456 MPa to 871 MPa;The elongation after fracture increased from 75.4％to 59.3％,a de-crease of only 16.1％.The excellent comprehensive mechanical properties are attributed to the fine grain strengthening,the precipitation hardening of the L12 phase,and the formation of a large number of annealing twins.
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