Mechanical And Corrosion Resistance Properties Of Zn-Sr Biodegradable Medical Materials

A set of Zn-xSr?x=0,0.5%,1%,2%,3%?binary alloy samples were prepared by smelting method.The set of Zn-xSr binary alloy samples were homogenized at 300C for 3h.The microstructure,mechanical properties and corrosion resistance of the as-cast and homogeneous Zn-xSr binary alloy were studied by a series of experiments:metallographic,XRD,microhardness tester,scanning electron microscopy?SEM?,electrochemical measurements and immersion test and weightlessness method and other instruments and methods.The results show that,with the increase of the content of strontium,the second phase(?59?₁₃)in the microstructure of zinc alloy gradually increases,and the size increases,resulting in the hardness of the alloy increases gradually,while the corrosion resistance is getting worse.The microstructure of homogeneous alloy is more uniform than as-cast alloy.The microhardness of the homogeneous alloy is higher tha n as-cast alloy,and the corrosion resistance of the homogeneous al oy is stronger than as-cast alloy.The effects of extrusion and rolling on microstructure and mechanical properties and corrosion resistance of Zn-1Sr and Zn-2Sr alloy were further studied.The results show that the second phase of the extruded Zn-1Sr and Zn-2Sr are badly broken.The second phase of Zn-1Sr and Zn-2Sr alloy with different rolling temperature mostly distributed flocky along the rolling direction.The microhardness of the extruded Zn-1Sr and Zn-2Sr alloy is higher than that of the as-cast and the homogeneous alloy.The microhardness of the rolled Zn-1Sr and Zn-2Sr alloy is lower than that of the as-cast and the homogeneous alloy.Both the extrusion and rolling process can improve the yield strength,tensile strength and elongation of the as-cast alloy.The corrosion trends of the extruded and rolled Zn-1Sr and Zn-2Sr alloys are all the same as those of as-cast alloys,and the corrosion rates are smaller than those of as-cast alloys,which indicates that the corrosion resistance of the as-cast Zn-1Sr and Zn-2Sr alloys is enhanced by extrusion and rolling process.