In the artificial implantation of biomedical metal materials, titanium alloy with its good biocompatibility, mechanical properties (high specific strength, low elastic modulus, etc.) and wear and corrosion resistance, As artificial joints (hip, knee, shoulder, ankle, elbow, wrist, knuckles, etc.), bone trauma products (nails, steel plates, screws, etc.), spinal orthopedic fixation system, dental implants, artificial heart valve, interventional cardiovascular stents, such as medical implant is ideal material of products, has been widely used in the field.
At present, titanium, niobium, tantalum and zirconium biomedical titanium alloys are mainly prepared by vacuum melting method. Due to the addition of refractory metal elements Nb, Ta and Zr in the alloy, its melting point and density are far greater than Ti, and it has the characteristics of poor plasticity and difficult deformation. Therefore, in the process of preparing the alloy, the vacuum melting method can not completely avoid the defects such as composition segregation, uneven structure, porosity and shrinkage cavity, which leads to the decrease of the mechanical and wear resistance and corrosion resistance of the material. In order to improve the composition segregation and casting defects of the material, it is often necessary to remelt the alloy more than three times, which not only increases the cost, but also brings the problem of material pollution. The titanium, niobium, tantalum and zirconium alloys prepared by vacuum melting method not only have high manufacturing cost, but also the mechanical properties of the materials can not meet the ideal requirements of clinical application, especially in large-scale production, which hinds its practical application in clinical practice.
Based on the problems existing in the process of preparing titanium, niobium, tantalum and zirconium biomedical titanium alloys by vacuum melting, new preparation methods need to be found. Powder sintering technology provides a new way to solve and improve the above problems. Spark Plasma Sintering (SPS) is a new advanced powder Sintering technology. Compared with the traditional vacuum Sintering method, The spark plasma sintering method has the advantages of fast rising and cooling rate (more than 100 C /min), short sintering time (generally about 15 min from heating up to the end of insulation), high density (up to 99%), clean preparation process and so on. Using this method to prepare titanium-niobium-tantalum-zirconium biomedical titanium alloys can overcome the shortcomings of traditional vacuum melting method, which can not only improve the composition segregation and microstructure of the alloy, but also make the alloy obtain high density, low elastic modulus, so as to have excellent comprehensive properties.
