Biomedical Titanium Alloy Material
Biomedical titanium alloy material is a kind of functional structural materials used in biomedical engineering, commonly used in the production and manufacture of surgical implants, orthopedic instrument products.Titanium alloy medical equipment products, such as artificial joints, dental implants and vascular stents for clinical diagnosis, treatment, repair, replacement of human tissue or organs, or enhance human tissue or organ function, its role is not a substitute for drugs.Medical titanium alloy material research involves materials, physics, chemistry, biology, medicine, electron microscopy and biochemical analysis and other disciplines, research directions include: medical metal alloy design and evaluation system, material processing-tissue-performance relationship with the human body soft and hard tissue compatibility matching, material surface modification(biocompatibility, biological functionality, biological activity, wear resistance and corrosion resistance, etc.) and material matrix and surface (interface) interaction law.
Pure titanium has the advantages of non-toxic, light weight, high strength, good biocompatibility and so on. In the 1950s, the United States and the United Kingdom began to use pure titanium for organisms. After the 1960s, titanium alloy began to be used as a human implant material and widely used in clinical. From the initial Ti-6Al-4V to the subsequent Ti-5Al-2.5Fe and Ti-6Al-7Nb alloy, with the development of new β titanium alloy in recent years, as shown in the following table, titanium alloy in human implant materials research has gained rapid development.
The density of titanium is similar to that of human bone, and it has light weight. Pure titanium biocompatibility is good, the strength is 390~490MPa. Experiments show that titanium compared to cobalt-based alloys and stainless steel fatigue resistance and corrosion resistance is superior, titanium surface activity is good, the tissue reaction is slight, easy to react with oxygen to establish a dense oxide film, titanium oxide layer is relatively stable.Therefore, titanium and titanium alloy with biomedical materials conditions, is a more ideal, suitable for implants, promising implant materials. Widely used in clinical titanium and titanium alloy manufacturing artificial joint parts, bone plates and screws, but also used to make artificial vertebrae (spinal braces), artificial heart (heart valves), artificial dental implants, pacemaker shell and so on.
Nitinol shape memory alloy is a shape memory alloy that can be plastically deformed into another shape after processing at a certain temperature and can be automatically restored to its original shape under certain conditions. Nitinol shape memory alloy fatigue limit is high,good corrosion resistance, which has a unique shape memory recovery temperature and human body temperature is appropriate, with good biocompatibility, and therefore has been widely used in the medical field.In recent years, nitinol shape memory alloy began to be used in the field of cardiovascular treatment, nitinol shape memory alloy stent can be applied to the treatment of coronary heart disease, with great prospects for development.
The application of titanium alloy in the field of biomedical applications shows a rapid development trend, combined with the research status quo at home and abroad,its future development direction is:
(1) Single crystal biomedical titanium alloy, a single crystal material obtained along a certain direction of growth can be obtained close to the elastic modulus of human bones, the production of implants will have a better elastic modulus match;
(2) Biocompatibility and industrialization of ultrafine crystal low elastic modulus and high strength titanium alloy;
(3) Regulation of microstructure properties of superelasticity and shape memory function of medical low elastic modulus titanium alloy;
(4) Adjust the size of the porosity to reduce the elastic modulus of biomedical porous titanium alloy material while improving its mechanical properties.
