Effect Of Rolling On Microstructure,mechanical Properties And Corrosion Resistance Of Zn-3Cu Alloy

Zinc and zinc alloys are expected to overcome the problems of too fast degradation of magnesium alloys and too slow dissolution of iron-based alloys because of their excellent properties such as containing essential trace elements,good biocompatibility and moderate degradation rate.The field of materials has huge application potential.However,the biomechanical properties such as low strength of zinc alloys developed today are incompatible,which significantly limits the scope of clinical applications.The development of high-strength bio-zinc alloys is currently a research hotspot in the field of biomedical degradable metal materials.Copper（Cu）is another trace element required for metabolism in the human body and has an indispensable physiological function for the body.In view of the low mechanical properties and other problems,this paper takes Zn-3Cu alloy as the research object,and firstly studies the effect of cold rolling deformation and strain rate on the microstructure,mechanical and corrosion resistance of Zn-3Cu alloy by cold rolling.Cryogenic treatment was carried out on the basis of cold rolling treatment to control the microstructure of Zn-3Cu alloy,improve the mechanical properties of the alloy,and analyze the influence of this treatment process on the corrosion performance of the alloy.The main research contents and results of this paper are as follows:（1）The effect of rolling deformation on the microstructure,mechanics and corrosion resistance of Zn-3Cu alloy was studied.The research results show that:with the increase of rolling deformation,the grain size of theα-Zn matrix phase gradually decreases,and the Cu Zn₅ phase is gradually elongated along the rolling direction;the strength of Zn-3Cu alloy increases first and then decreases,and the plasticity increases continuously.The tensile strength at 60%deformation reaches a maximum of 263.1±4.9 MPa,the yield strength and hardness at 40%deformation reach a maximum of 234.8±4.5 MPa and 88.7±2.2 HV,and the elongation at 90%deformation is 67.6±2.7%;Zn-3Cu alloy resists The corrosion performance continued to weaken,and the corrosion rates of 90%deformation in the electrochemical test and immersion test in Hank’s solution were 245.0±7.1μm/y and 33.6±1.1μm/y,respectively.（2）The effects of rolling strain rate on the microstructure,mechanics and corrosion resistance of Zn-3Cu alloy were studied.The research results show that the rolling strain rate is larger,the grain size of the matrix phase is smaller,and the deformation degree of the Cu Zn₅ phase is lower;the tensile strength and hardness of the Zn-3Cu alloy are improved,and the 60%deformation of strain rate 10 s^-1 is the largest,the tensile strength is 277.7±4.6MPa and the highest hardness value is 88.2±2.7 HV;the yield strength and elongation first decrease and then increase,and the elongation at 90%deformation of strain rate 15 s^-1 reaches95.2±3.2%;the corrosion resistance of Zn-3Cu alloy is enhanced.The slowest corrosion rate measured by the electrochemical test and immersion test in Hank’s solution at 60%deformation of strain rate 10 s^-1 is 180.5±15.6μm/y and 25.3±0.8μm/y,respectively.（3）The effects of rolling and cryogenic treatment on the microstructure,mechanics and corrosion resistance of Zn-3Cu alloy were studied.The research results show that:after cryogenic treatment,the grain size of the matrix phase is smaller,and the deformation degree of Cu Zn₅ phase is lower;the tensile strength and hardness of Zn-3Cu alloy are enhanced,and the maximum tensile strength of 60%deformation is 287.9±3.7 MPa,The hardness value of 40%deformation reaches 96.4±2.3 HV;the elongation of 90%deformation reaches 100.8±2.9%,and the elongation of other deformation decreases;the corrosion resistance of Zn-3Cu alloy is improved;and the corrosion resistance of 40%deformation is the best.The corrosion rates measured by electrochemical test and immersion test in Hank’s solution were165.9±11.3μm/y and 23.4±0.6μm/y,respectively.