The Study On The Biodegradable Magnesium Matrix Composite Application For Internal Bone Fixation

Biomedical magnesium alloy and its composite materials as bone implant material have caused wide attention.Magnesium alloys is a new generation of biomedical materials,it overcome the poor mechanical properties of biomedical polymer materials and the non-biodegradable of metal materials in clinic.Magnesium alloy has promising application in bone internal fixation,stent and vascular anastomosis nails field.So the study on magnesium alloy and its composite materials have very important significance.In this paper,Mg-3Zn-0.8Zr alloy and 2?-TCP/Mg-3Zn-0.8Zr composite were casted to study the effect of the addition of ?-TCP to the hot deformation behavior of Mg-3Zn-0.8Zr alloy.The surface of nano ceramic particles ?-TCP and HA were coated by MgO(m-?-TCP and m-HA),as-extruded 1?-TCP/Mg-3Zn-1.6Zr composite,1m-?-TCP/Mg-3Zn-1.6Zr composite,1HA/Mg-3Zn-1.6Zr composite and 1m-HA/Mg-3Zn-1.6Zr composite materials were casted to study the microstructure,mechanical property and corrosion resistance of them.The results show that: 1.Dynamic recrystallization was occurred at the process of hot extrusion of Mg-3Zn-0.8Zr alloy and 2?-TCP/Mg-3Zn-0.8Zr material.The plastic deformation of alloy become more difficultly because of the addition of nano ceramic particles ?-TCP.The best thermal deformation temperature range of Mg-3Zn-0.8Zr alloy and 2?-TCP/Mg-3Zn-0.8Zr material is 250-300 ? and 300-350 ? respectively.2.Compeared to 1?-TCP/Mg-3Zn-1.6Zr composite,the grain of 1m-?-TCP/Mg-3Zn-1.6Zr composite is uniforrn and fine,the corrosion rate of 1m-?-TCP/Mg-3Zn-1.6Zr composite decreased to 8 mm/y,the YTS(yield tensile strength)and UTS(ultimate tensile strength)of 1m-?-TCP/Mg-3Zn-1.6Zr composite increased to 295.578 MPa and 326.11 MPa respectively.3.The grain of 1m-HA/Mg-3Zn-1.6Zr composite is smaller than 1HA/Mg-3Zn-1.6Zr composite.After the modified of nano ceramic particles HA,the YTS and UTS of the composite material increased to 291.106 MPa and 324.829 MPa respectively,the corrosion rate of the composite material decreased to 13 mm/y.