Alloying Elements Cd And Nd Zk60 Magnesium Alloy Mechanical Properties And Corrosion

The influence of Cd and Nd on the microstructure,mechanical properties and corrosion resistance of ZK60 alloy was investigated by optical microscopy(OM),X-ray diffraction(XRD),scanning electronic microscopy(SEM) and transmission electron microscopy(TEM).Some experiment results are obtained as follows.1.The dynamically recrystallized grain size and the recrystallization volume fraction of ZK60-1.7Nd-0.7Cd alloy increase with increasing deformation temperature under the same strain rate and reduce with increasing strain rate under the same deformation temperature.2.The addition of Cd or Nd can refine the microstructures and improve the yield strength of ZK60 alloy.The effect of Cd addition on grain refinement is better than that of Nd addition while the effect is the best for the co-addition of Cd and Nd.Cd completely dissolved in Mg matrix,which results in increasing of the yield strength of ZK60 alloy.Owing to the addition of Nd,a Nd₃Mg₆Zn₁₁ phase appears,which blocks the movement of dislocation lines and improve the strength.Owing to the co-addition of Cd and Nd,the grain size of as-cast ZK60 alloy can be refined to 35μm and as-extruded ZK60 alloy can be refined to 7μm.For as-extruded ZK60 alloy,the yield strength can be improved to 300MPa and the ultimate tensile strength can be improved to 334MPa.3.After T6 treatment,the strength of ZK60-1.7Nd-0.7Cd alloy decreased.The heat treatment of as-extruded ZK60-1.7Nd-0.7Cd alloy should adopt T5 treatment.The optimum process condition of T5 treatment is 120℃/15h.After T5 treatment(120℃/15h),the yield strength of as-extruded ZK60-1.7Nd-0.7Cd alloy increased to 315MPa and the ultimate tensile strength improved to 349MPa.4.Owing to the co-addition of Cd and Nd,the corrosion resistance decreased.The corrosion resistance of as-T5 treatment ZK60-1.7Nd-0.7Cd alloy is better than as-extruded ZK60-1.7Nd-0.7Cd alloy,and as-extruded ZK60-1.7Nd-0.7Cd alloy is better than as-cast ZK60-1.7Nd-0.7Cd alloy.