Study on Microstructure and Mechanical Properties of CrCoNi Medium Entropy Alloy with Two Different Processing States
Medium entropy alloy is a hot topic in material research in recent years.The process of casting-rolling-heat treatment is generally adopted for medium entropy alloy.XRD,metallographic microscope,universal testing machine and scanning electron microscope were used to study the metallographic structure,hardness,mechanical properties at room temperature and low temperature(77 K)and tensile fracture of entropy alloy in CoCrNi as cast and rolling+heat treatment.The results show that of as-cast CoCrNi alloy rolling+heating processing,two different state alloy are stable face-centered cubic(FCC)phase,the as-cast microstructure for typical dendrites,but there are no obvious second phase.The rolling+heat treatment has obvious effect on the microstructure of refining and homogenizing effect,the tensile strength and hardness of the material has obvious improvement.The tensile properties of the two alloys in different processing states improves obviously at low temperature.The tensile strength and elongation of the entropy alloy can reach 1262.9 MPa and 89.6%at liquid nitrogen temperature in the post-rolling heat treatment,and the plastic fracture of the entropy alloy in the two states occurs at different temperatures.The plastic deformation behavior of CoCrNi alloy is mainly slip-slip at room temperature,and twinning at low temperature.
CoCrNi medium entropy alloyrolling and heating treatmenttensile property at low temperaturetensile strengthtensile elongation
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