Since the middle of the 20th century, medical metal materials based on titanium alloys have been shown in surgical implantation of human hard tissues and interventional treatment of human soft tissues (including cardiovascular and cerebrovascular, peripheral and nonvascular vessels such as liver, biliary tract, urethra, etc.) It has a unique and magical effect, and the development, production and application of titanium alloy materials for medical devices such as titanium alloy artificial joints, dental implants, intravascular stents and heart valves, and the advent of typical representative medical device products The development has epoch-making significance and revolutionary contribution, which makes the clinical treatment rise from the primary simple "repair, orthopedic" treatment to a higher level of "alternative" treatment of tissues and organs, which greatly improves and improves the quality of life of people, Overcome the shortcomings of the past major diseases can only rely on drug treatment.
1. The development history of titanium alloy materials in China
In the early 1970s, China began to use domestically produced titanium and titanium alloy products
In many hospitals in Beijing, titanium and titanium alloy artificial bones and joints have been used for clinical treatment applications and research, and titanium alloy hip joints, elbow joints, mandibles, etc. are used for clinical treatment of patients. At the same time, some hospitals and companies conducted immersion experiments to simulate human body fluids, electrochemical anodization experiments and measurement of corrosion kinetics curves, proving that titanium and titanium alloy artificial bones and joints have excellent corrosion resistance and biocompatibility for human body It is an ideal human implant. The mechanical properties of implanted human bones and joints have also been determined. It is believed that the strength of titanium and titanium alloys meets the requirements of human implants.
After the mid-1980s, the number of titanium materials used in China to manufacture human implants has increased, and the development and application of titanium shape memory alloys have reached the international advanced level. By the mid-1990s, titanium and titanium alloy processing materials produced in China were widely used in orthopedic surgery, neurosurgery, cardiovascular system, oral and maxillofacial surgery, and human in vitro culture machine. In the past five years, China has grown a large number of enterprises to become titanium and stainless steel and other human implant manufacturers. Titanium and titanium alloy-made femoral head, hip joint, humerus, skull, knee joint, elbow joint, shoulder joint, metacarpophalangeal joint, jawbone and heart discriminator, kidney discriminator, vasodilator, splint, prosthesis, Hundreds of metal parts such as fastening screws have been transplanted into the human body and achieved good results, which have been highly praised by the medical community.
2. Classification and characteristics of biomedical titanium alloy materials
Biomedical titanium alloy materials refer to a class of functional structural materials used in biomedical engineering, mainly used in the production and manufacturing of surgical implants and orthopedic devices. According to the professional standards of surgical implants and orthopedic devices, titanium alloy materials can be classified as "metal materials" in "materials for surgical implants", while titanium alloy materials are used in non-active surgical implants and active surgical implants. Three types of medical devices, including implants and orthopedic devices, can serve as cardiovascular, bone and joint, bone joint, spine, orthopedic devices, cardiac pacemakers and defibrillators, cochlear implants, neurostimulators and other implants The raw material of the product. Biomedical titanium alloys can be divided into α-type titanium alloys (such as pure titanium series), α+β-type titanium alloys (such as Ti6Al4V, etc.) and β-type titanium alloys (such as Ti12Mo6Zr2Fe, etc.) and TiNi shape memory titanium according to the material microstructure type Four types of alloys, compared with medical stainless steel and cobalt-based alloys, they have the characteristics of small specific gravity, high specific strength, low elastic modulus, corrosion resistance, easy cutting and good biocompatibility.
3. Research and development status of biomedical titanium alloy materials
The development of biomedical titanium and its alloys can be divided into three eras: the first era is represented by pure titanium and Ti6A14V, the second era is a new type d+B alloy represented by TiA12.5Fe and Ti6A17Nb, and the third Times is an era of developing and developing titanium alloys with better biocompatibility and lower modulus of elasticity, among which the most extensive research is on B-type titanium alloys.
1) The first-generation biotitanium alloy industrial pure titanium represented by pure titanium and Ti6A14V is the first titanium alloy to be used in this field. At present, the clinical experience of using pure titanium implants is relatively mature, but commercial pure titanium does not provide the comprehensive mechanical properties required for medical load-bearing materials.For example, pure titanium has low strength and poor wear resistance, which limits its application. . Although cold working can increase the strength of pure titanium, it can not meet the actual needs. Therefore, people began to consider the use of titanium alloys. Ti6A14V is the first titanium alloy to be introduced into the field of biomaterials due to its excellent biocompatibility and good comprehensive mechanical properties, and it is still the largest titanium alloy in biomedical device products.
2) The second generation of new Q+B type alloys represented by Ti6A17Nb and TiSAl2.5Fe due to the potentially toxic element V in Ti6M4V, two new “q+B” type medical titanium alloys TiSAl2.5Fe and Ti6A17Nb in the mid-1980s Europe has developed.
Ti6A17Nb is comparable to the recognized "all-round" Ti6A14V alloy in mechanical properties. It is a safe and promising artificial biomedical implant material. It was successfully developed by Switzerland in 1989. Experts and scholars from various countries of this safe and promising biomedical titanium alloy have conducted in-depth research in different aspects.
4. Production status of titanium alloy materials for medical devices in China
China first published the first national standard GB/T13810-1992 "Ti and Titanium Alloy Processing Materials for Surgical Implants" in 1992, which marked the beginning of China's professional production of titanium alloy raw materials for medical device applications. China currently mainly produces pure titanium (Chinese grade TA1~TA4, American corresponding grade Gr1~Gr4), Ti6Al4V (Chinese grade TC4, American corresponding grade Gr5 or Ti64), Ti6Al7Nb (Chinese grade TC20) three major types of titanium alloy materials, there is no β-type titanium alloy is included in the national standard. Up to now, pure titanium and Ti6Al4V titanium alloy are still the most widely used and widely used traditional body materials for surgical implants in the world, and their sales account for about the entire global biomedical titanium alloy market. More than 80%.
The varieties of titanium and titanium alloy processed materials for surgical implants currently produced in China involve plates (thickness 0.8~25mm), rods and wires (diameter 1~90mm), and the supply status can be cold rolled, hot processed and annealed . The chemical composition, mechanical properties and microstructure of titanium alloy processing materials specified in China's new national standard GB/T13810-2007 are equivalent to the requirements of the US ASTM F136-02a, but at the same time, the microstructure rating, section shrinkage and Additional technical requirements such as ultrasonic inspection of plates and bars. The Chinese national standard clearly stipulates that the microstructure rating type of Ti6Al4V titanium alloy should be in accordance with the a+b dual-phase structure of A1~A9. The bar can reach A1 level (equiaxed a and b phase grain size is less than 10μm), so it has excellent toughness, corrosion resistance and mechanical cutting performance, which meets China's artificial joints, dental implants, and spinal internal fixation The demand for high-end medical equipment such as systems, but there are still high-end products processing still need to import foreign high-quality Ti6Al4V titanium alloy materials.
In 2008, China's sponge titanium and titanium materials production ranked first and second in the world, respectively, and titanium material consumption has occupied the second place in the world.It has become a major titanium industrial country after Russia, the United States, and Japan. Consumption is mainly for defense military use, while China and Japan are mainly for industrial civilian use.