Development and Application Progress of Biomedical Titanium and Alloy Materials

1.Overview

Biomedical materials are an important branch of materials science,which are new carrier materials with high technological content and economic value used for diagnosis,treatment,or replacement of human tissues,organs,or enhancement of their functions.They are a developing new field in materials science and technology.Biomedical materials make greater contributions to exploring the mysteries of human life and ensuring human health and longevity.

Over the past decade,the market growth rate of biomedical materials and products has been maintained at around 20%-25%.It is expected that within the next 10-15 years,the medical device industry,including biomedical materials,will reach the scale of the pharmaceutical product market and become a pillar industry of the world economy in the 21st century.

In biomedical metal materials,titanium and its alloys have become the preferred materials for medical implant products such as artificial joints(hip,knee,shoulder,ankle,elbow,wrist,finger joints,etc.),bone trauma products(intramedullary nails,steel plates,screws,etc.),spinal corrective internal fixation systems,dental implants,dental brackets,dental orthodontic wires,artificial heart valves,interventional cardiovascular stents,etc.,due to their excellent comprehensive performance.At present,there is no better metal material for clinical use than titanium alloy.Developed countries and world-renowned suppliers of implant products attach great importance to the research and development of titanium alloys,launching a series of new medical titanium alloy materials,including biologically active titanium alloy biomimetic materials.They have also made many patented designs and developments in the surface treatment of medical titanium alloy materials,endowing them with better biological activity to meet the physiological needs of the human body,So as to achieve the goal of early recovery for patients.

The world population is nearly 6.5 billion.According to incomplete statistics,there are nearly 400 million disabled people,60 million physically disabled people,and 2 billion dental patients.Currently,there are only 35 million people implanted with biomaterial devices,and the annual joint replacement volume is about 1.5 million,which is far from the actual number of people in need of replacement.Therefore,the demand potential for biomedical materials in the market is enormous.As the first choice for biomedical metal materials,the demand for titanium and its alloys will also increase significantly.Therefore,it is imperative to increase the research and development efforts of medical titanium alloy materials.

2.Development history,latest progress,and market situation of biomedical titanium and its alloy materials

The development and application of biomedical titanium and its alloy materials have gone through four iconic stages.

2.1 Initial application stage

In the early 1950s,commercial pure titanium was first used in the UK and the US to manufacture plates,screws,intramedullary nails,and hip joints.Due to the need to shape the bone plate during surgery in order to adhere to the physiological and anatomical shape of the fractured bone,commercial pure titanium(IS05832-2)that has undergone special processing is still used to manufacture bone plates and matching screws,such as the full range of AO steel plates and screws produced by the designated manufacturer of AO bone fixation implants,Mathys Medical Ltd.,Switzerland,which cannot be replaced by high-strength titanium alloys.Clinically,it has been found that the use of commercial pure titanium to manufacture intramedullary nails and hip joints has significant issues of insufficient strength and stiffness.In order to avoid the fracture and failure of internal fixation implants and improve their strength,high-strength Ti-6A1-4V(IS05832-2)alloy has been used instead of pure titanium materials in countries such as the UK,US,Russia,and Japan.

2.2 Development stage

The Ti-6A1-4V alloy itself is also developing,with the emergence of Ti-6A1-4VELI high damage tolerance titanium alloy with high fracture toughness,low crack propagation rate,and low gap elements.Until now,more than 80%of titanium alloy implant products still use this alloy.

Although Ti-6A1-4V alloy has excellent performance,due to the fact that V element can cause malignant tissue reactions and may have toxic side effects on the human body,it has prompted materials scientists to study new titanium alloy materials that do not contain V.Since the 1980s,biomaterialists from Germany and Switzerland have successively developed Ti-5A1-2.5Fe and Ti-6A1-7Nb alloys.Among these two alloys,the clinical application of Ti-6A1-7Nb(IS05832-11)alloy is more successful.In 1985,Rui Sulzer Medical Technology Company first used forged Ti-6A1-7Nb Protasu1100 material to manufacture hip joint stems and obtained quasi production registration[2].It was used in clinical practice and has received good market feedback.Currently,this type of product has been introduced to China.Swiss company Mathys also uses Ti-6AI-7Nb alloy to manufacture non expanding intramedullary nail systems(including tibia,humerus,femur)and hollow screws for the treatment of femoral neck fractures.

2.3 Improvement stage

Since the 1990s,there have been continuous reports on the potential harm of AⅡto the human body in the field of titanium alloy implant materials.It is believed that A1 can cause diseases such as osteoporosis and mental disorders.Therefore,biomaterialists have begun to explore and study new biological titanium alloys that do not contain V and A1.The alloys that have been successfully developed and clinically approved include Ti-13Nb-13Zr alloy(ASTM F1713-1996)and Ti.12Mo-6Zr-2Fe alloy(ASTM F1813-1997).

Ti-13Nb-13Zr alloy is a bio titanium alloy developed by American scientists in the early 1990s,which has excellent comprehensive properties such as low elastic modulus,high strength,high toughness,high fatigue strength,and good biocompatibility.Compared with Ti-6A1-4V,its elastic modulus is 30%lower and its plane fracture toughness is 20%higher(65MPa.m1/2);The bending and shear modulus is 30%-40%lower,and the corrosion rate is 40%lower in the same human simulated body fluid.After cold and hot processing,while maintaining high strength,the modulus can decrease to 50MPa,which is closer to human cortical bone[3].At present,this material is used by internationally renowned dental material manufacturers to manufacture dental implants.

Ti-12Mo-6Zr-2Fe alloy is also a biomedical titanium alloy that has been highly praised by internationally renowned metal implant manufacturers in recent years.This alloy has low elastic modulus,high strength,high fracture toughness(90MPa.m1/2),good wear resistance,and excellent corrosion resistance.It is a metastable p-type biomedical titanium alloy with good comprehensive performance.Compared with Ti-6A1-4V,its elastic modulus is 25%lower,the material has better flexibility,and the fracture toughness is about 80%higher(90:52).It also has excellent mechanical properties:tensile strength is 20%higher than Ti-6A1-4V,and fatigue strength is 47%higher.One of the largest orthopedic professional group companies in the world??Stryker Howmedica Osteonics,a subsidiary of STRYKER Group,uses Ti-12Mo-6Zr-2Fe alloy(TMZFR BETA)to manufacture the MeridianTMZF femoral stem in the Howmedica Partnership system(hip prosthesis system),which meets the highest standards of orthopedic clinical requirements in terms of quality,function,and clinical efficacy??Top tier.Stryker SPINE also uses TiMoZrFe alloy to manufacture the REFLEX Anterior Cervical Hat system.The above two products have been introduced to the Chinese market.

2.4 Innovation stage

Without innovation,there can be no progress.In recent years,there have been many innovative achievements in the field of medical titanium alloys.

(1)Development and Application of Ni Ti Shape Memory Alloy(NTSMA)

In the early 1980s,Ni Ti shaped memory alloy was successfully used in orthopedic clinical practice,attracting the attention of orthopedic experts and clinical doctors,and was referred to as the"magical metal".This functional material has unique shape memory effect,super elasticity,fatigue resistance,wear resistance,corrosion resistance,and good biocompatibility.It is composed of 56%(mass percentage)Ni and 44%(mass percentage)titanium.The deformation temperature of NTSMA used in orthopedic clinical practice is 0℃-5℃,and the recovery temperature is around 37℃.After using NTSMA material to fix a fracture,the shape recovery is produced by heating up under body temperature or hot saline wet compress.However,the bone restricts the material recovery,which generates a dynamic and continuous pressure or clamping force at the fracture end to achieve the effect of fixing the fracture.The basic research of NTSMA materials in China is later than that in foreign countries,but it is in an international leading position in clinical application research.In 2000,in the field of orthopedic implants,Lanzhou Ximai Memory Alloy Co.,Ltd.obtained product registration from the National Medical Products Administration,promoting the clinical application of NTSMA orthopedic implants.At present,three enterprises in China have registered and produced NTSMA bone fixation devices,mainly including riding screws,patellar concentrators,embracing steel plates,Ni Ti arch shaped memory compression connectors,intramedullary nails,and other products.

NTSMA is also used in interventional therapy.Interventional therapy is an advanced non-surgical clinical technique that has developed rapidly in the past decade.This technology is usually used under X-ray image monitoring,using puncture intubation technology to transport specially designed wires,catheters,balloons or support brackets along blood vessels or other lumens in the body to the site of the lesion for on-site treatment.It has the characteristics of light trauma,low pain,low risk,time-saving,reliable,and fast recovery.Interventional treatment materials include stent materials and delivery system materials,among which NTSMAo is the preferred stent material.In recent years,the development of interventional treatment in China has been rapid,with an annual growth rate of 20%-30%.In 2002,nearly 150000 patients received interventional treatment.At present,the materials required for interventional therapy mainly rely on imports,and more than 20 enterprises have obtained FDA certification to enter the Chinese market.Its product quality and performance are superior to domestic products,and the after-sales service is in place,but the price is expensive,about 12000 yuan/piece to 16000 yuan/piece.The main suppliers include JOHNSON&JOHNSON COMPANIY CORDIS CO.from the United States,MEDTRO NIG,INC from the United States,and NUMED CANADA INC from Canada;There are also some companies in China that produce,such as Beijing Sitai New Technology Development Company,Beijing Xinquan Company,and Beijing Longzhou Feidu Memory Alloy Application Research Institute.

In addition,NTSMA is also used in orthodontic treatment.The NTSMA dental arch wire produced by the Rare and Precious Institute of Beijing Nonferrous Metals Research Institute(now Beijing Youyan Yijin Co.,Ltd.)is not only sold and applied domestically,but also exported overseas.

(2)Manufacturing of cervical and lumbar interbody fusion cages(Cage)using porous Ni Ti(PNT)alloy bioactive materials

BIORTHEX,a Canadian company,has developed a cervical and lumbar interbody fusion cage using a patented porous Ni Ti alloy material,ACTIVORETM,for the treatment of orthopedic spinal injuries.This material has a porosity of about 65%and an average pore size of 215μM-230μm.It has biological activity and promotes the rapid growth of new bone through micropores and scaffolds.The multi-directional micropores connected internally generate capillary permeation,promoting blood,basic nutrients,and bone marrow to enter the intervertebral fusion cage.This metal implant material has an elastic modulus similar to that of cancellous bone,thus avoiding stress shielding effects,promoting bone reconstruction,and providing good environmental support for bone cell growth.Bone growth cells and nutrients penetrate into the interconnected micropores,accelerating bone integration.The biggest feature of this intervertebral fusion device is that it does not require bone grafting(other materials require bone grafting,using their own iliac bone).After 3.1 years of grafting,bone reconstruction is completed inside the fusion device and matches the surrounding bone density.Animal experiments have shown that PNT alloy has good biocompatibility[5,6].In 2000,the product obtained CE certification and began selling in European and some Asian markets.Currently,stricter clinical validation is being intensified in order to apply for FDA certification in the United States.This product is also expected to be introduced to the Chinese market in the near future.

(3)Manufacturing of artificial hip prosthesis using porous titanium alloy

Biofixed(non cemented)artificial joints are currently highly regarded artificial joint prostheses by experts and clinical doctors in the field of orthopedics.It requires the material or surface of the hip joint stem to have biological activity,which can induce bone cell growth,resulting in bone integration at the interface between the joint stem and the femoral medullary cavity,thereby avoiding the drawbacks of using bone cement fixation,which may cause loosening,sinking,and dislocation after long-term use.Therefore,the use of porous titanium alloy materials in some stages of the joint stem will endow the prosthesis with biological activity,which helps to facilitate the osseointegration between the stem and the medullary cavity.In the late 1990s,scientists from Germany and Japan successfully used directional solidification technology to prepare directionally solidified porous metal materials(i.e.foam metal)with hydrogen,oxygen and nitrogen as foaming gases.Krupp,gb Implantat Technologie GmbH,uses this technology to produce porous titanium alloy femoral stem prostheses.

(4)Porous titanium alloy coating technology for the manufacturing of artificial joint prostheses

Another method for manufacturing bio fixed artificial joints is to create pores on the surface of titanium alloy joint handles.Small titanium bead particles(microsphere powder)can be sintered or plasma sprayed onto the surface of the joint stem,making the surface porous and reducing the difference in elastic modulus between the implant and bone.This is beneficial for the growth of bone cells and the delivery of nutrients,thereby achieving physiological bone integration.The American Exactech AcuMatchtm-A series uses titanium beads with a diameter of 0.28mm at the proximal end of the hip joint stem,arranged in a three-dimensional manner.After sintering,the combined size of the three rows of beads is 0.84mm,and the average pore size is 152μm.The average porosity is 35%,indicating that there is 35%bone growth space on the surface of sintered titanium beads at the handle.

Most bio fixed joint prostheses(hip and knee joints)are coated with porous spray(titanium microsphere powder)on the surface,such as Zimmer,Exactech,Taiwan United Company,etc.In addition to using titanium alloy beads(microspheres)for plasma spraying,in recent years,Encore Medical Corporation in the United States has invented the 3DMatrixTM porous spraying technology.This technology does not use spherical particles,but rather a random three-dimensional irregular particle with a particle size of 180μM-850μm.Surface aperture size after spraying:250μM-450μm.The porosity can reach 61%.Clinical studies have shown that:100μM-500μThe aperture size of m is most suitable for bone growth.This advanced porous spraying technology provides better biological activity on the surface of the prosthesis stem and provides a better bone growth interface.

(5)Hydroxyapatite(HA)coating technology for titanium alloy artificial joint manufacturing

Using plasma spraying technology to spray hydroxyapatite(HA)coating on a part of the joint prosthesis stem is also one of the methods for manufacturing bio artificial joints.Structurally speaking,human bone itself is a natural composite material composed of osteogenic fibers and hydroxyapatite.Hydroxyapatite(Ca5(0H)(P04)3)contains hydroxyl groups that can bond with human tissue.Its chemical composition and crystal structure are very similar to hydroxyapatite crystals that make up human tissue.After implantation into human hard tissue,it bonds well with bone and can induce bone tissue to grow into micropores,with mild tissue reactions.After several months of implantation,bone bonding can generally be achieved at a tightly fitted interface,making it the preferred coating material in bioactive ceramics.

The bonding strength between HA coating and titanium alloy substrate is the key factor affecting the clinical use effect of titanium alloy implants.As long as there is a macroscopic interface between the coating and substrate,the bonding strength between the two cannot be satisfactory.The general requirement is that the bonding strength between the coating and the titanium alloy substrate should not be less than 40MPa,and the coating thickness should be 150μM-200μM.The coating is too thick,the bonding strength decreases,and the coating is prone to cracking.Therefore,the entire plasma spraying process is operated by robots to ensure uniform and consistent coating thickness.The coating contains micropores and larger pores,with porosity and randomness.The pore size of micropores is 3μM-5μm.The aperture size of the larger hole is 50μM-100μM.The size of the pore size can be detected under scanning electron microscopy,while HA must maintain continuous purity(generally above 99.9%)and stable crystalline structure.

Most domestic and foreign joint product manufacturers use this technology to manufacture bio titanium alloy artificial prosthetic stems.

(6)Application of Al2O3 ceramic coating technology in the manufacturing of titanium alloy artificial joints

Using plasma spraying technology to achieve a purity of 99.8%α?Al2O3 micro powder is sprayed onto the stem of hip joint prosthesis(stem material Ti6A14V),and then cooled in liquid CO2 to form an interface at its interfaceγ-Al2O3 requires that the crystalline strength of the matrix and A1203 should not be less than 20MPa,which is also one of the methods for manufacturing bio type(non bone cement)artificial joints.Al2O3 ceramic material is also used to manufacture the lining of hip joint ball heads and hip acetabulum.After autopsy of the deceased who used the above-mentioned materials to manufacture prostheses and other clinical tests,it was observed that the debris of A1203 ceramic material did not cause inflammatory reactions in the synovial tissue of the joint capsule,and no synovial hyperplasia or necrosis was observed.This type of prosthesis is most suitable for patients who are younger and have a higher postoperative activity.It can be seen that Al2O3 ceramic material has excellent biocompatibility with human tissues.Al2O3 ceramic materials also have high physical stability,no biological degradation,excellent hydrophilicity on the material surface,and can effectively form water molecule films to reduce friction,hardness,and fatigue.High labor intensity and wear resistance are 30-40 times higher than CoCrMo alloy.The joint products of Italy's LIMA Orthopedic Equipment Company and France's SERF Medical Technology Company both use this manufacturing method and process.The joint products of Baimu Aviation Materials Company of Beijing Institute of Aeronautical Materials in China also adopt this process.

(7)Hydroxyapatite(HA)-glass titanium composite material for artificial joint manufacturing

In the late 1990s,Japanese materials scientists such as Shigeo Maruno developed a new type of biomedical titanium alloy composite material for manufacturing artificial joints.This material is based on Ti-6A1-4V alloy as the matrix,and glass powder(alumina borosilicate glass,i.e.Al2O3-B2O5-SiO2,with a volume percentage of about 85%,and the rest being glass modified oxides Na2O,K2O,Li2O,ZrO2,and TiO2)with good adhesion to the matrix material,stable biochemical and safety properties,minimal reaction with HA,and excellent bonding performance with HA powder(alumina borosilicate glass,i.e.Al2O3-B2O5-SiO2,with a volume percentage of about 85%,and the rest being glass modified oxides Na2O,K2O,Li2O,ZrO2,and TiO2).The average diameter of the glass powder is 17μm)And high-purity HA powder is mixed and coated on the surface of the titanium alloy matrix to form a glass titanium composite material containing HA by sintering.Another key aspect of this material research is that the thermal expansion coefficient of the sintered composite layer is lower than that of the titanium alloy matrix.Only in this way can the contact interface between the composite layer and the titanium alloy matrix generate a dense,stable,and tightly bonded composite layer due to thermal diffusion reaction.

The artificial hip joint stem made of HA-G-Ti composite material has been preliminarily clinically validated as a durable and cost-effective artificial hip joint prosthesis with excellent initial fixation.The thickness of the HA-G composite layer can be adjusted arbitrarily,with excellent biocompatibility.The HA-G composite layer has good bonding with the matrix,and no peeling or cracking has been found.The long-term clinical efficacy needs further observation,so this material is also a biomedical titanium alloy material with great market development potential[7].

(8)Anodizing and coloring treatment of titanium and its alloy surfaces is used in orthopedic equipment,plastic surgery,and dentistry.

Anodizing and coloring treatment of titanium and its alloy surfaces,in terms of functionality,improves the wear resistance,corrosion resistance,and cyclic fatigue resistance of the titanium alloy substrate in the human environment by coating the surface with an oxide film.In addition,the oxide film on the surface also largely solves the problem of metal ion leaching,reduces cell toxicity,and greatly improves the biocompatibility of the implant.For its aesthetics,with the increasing variety and specifications of titanium alloy implants,it has also brought difficulties to clinical identification.The color of the surface oxide film,as a unique property of titanium alloy,can be used to identify different specifications and categories of implants during surgery,facilitating surgical operations.In addition,due to the good biocompatibility,corrosion resistance,lightweight,and comfortable wearing of titanium,its clinical application as dentures(dental implants)and plastic surgery restorations is gradually increasing.The restoration of dentures by people not only emphasizes the restoration of functions such as chewing,pronunciation,and service life,but also demands an increasing demand for the aesthetics of dentures.The color beauty of dentures can provide visual enjoyment.In terms of plastic surgery repair,this advantage is even more obvious.

The reason why titanium surfaces show different colors after oxidation is because the main component of the oxide film formed on the surface of metallic titanium is titanium oxide.The thin film like material composed of this component is transparent and can strongly reflect and refract light.When heating titanium in an oxygen-containing atmosphere or performing anodizing treatment on titanium,a layer of several hundred A thick titanium oxide film is coated on the surface of titanium.If light is irradiated on titanium coated with an oxide film,the reflected light on the surface of the oxide film will interfere with the light reflected through the metal interface of the transparent oxide film,resulting in various beautiful interference colors[9].As the thickness of the oxide film varies,the surface of titanium can exhibit various colors such as yellow,green,gold,and pink.

The oxidation coloring of titanium mainly includes anodizing,atmospheric oxidation,and chemical treatment.In addition,there are methods such as plasma nitriding,nitrogen ion implantation,and physical chemical vapor deposition.

Compared with the other two oxidation coloring methods of titanium,anodizing is the most promising oxidation coloring technology due to its simple process,rich color tone of surface coloring,and easy control of color tone.

Internal fixation implants and instruments are usually treated with anodizing for surface coloring,with colors including gold,bronze,sapphire blue,bright brown,rose red,and elegant green.

3.Preliminary analysis of the current situation and existing problems in the research,development,sales,and market application of biomedical titanium and its alloys in China

3.1 Research and development,market application status of biomedical titanium and its alloys

Since the mid-1980s,China's clinical and applied research on nickel titanium shape memory alloys in the field of medical implants has reached an international advanced level.Shanghai Iron and Steel Research Institute,Tianjin Institute of Metallurgical Materials,and Beijing Institute of Nonferrous Metals Research Institute have jointly developed many medical implant products with local medical experts and professors.For example,products such as embracing steel plates,patellar claws,riding nails,intramedullary nails,artificial joints,dental arch wires,etc.But it was not until 2000 that the first nickel titanium shape memory alloy product(from Lanzhou Ximai Memory Alloy Co.,Ltd.)was registered for production approval by the National Medical Administration.

Although China has abundant titanium reserves,it lags behind in the field of medical titanium,and cannot compare with European and American countries in terms of scientific research,equipment,technology,process,and application.In 1998,Tianjin Medical Device Industry Company Orthopedic Device Factory II became the first domestic titanium implant production enterprise to obtain the trial production registration of"titanium bone plates"and"titanium bone screws"issued by the National Medical Administration.The enterprise achieved good economic benefits that year.In the following years,titanium implants will be produced by domestic medical device manufacturers like mushrooms after rain.At present,domestic enterprises with good applications include Changzhou Wujin Medical Device Factory III and Changzhou Kanghui Medical Device Co.,Ltd.However,many problems have also occurred during the specific use process,such as implant fatigue and fracture,difficulty in shaping during surgery,and even many medical disputes,which are closely related to the selection of materials.

In 1992,China formulated the standard for titanium and its alloy processing materials for surgical implants(GBl3810-1992),but there were very few types of alloys.In 1997,the above standard was revised,namely GB/T13810?1997.However,in practical use,surgical implant manufacturers have not fully understood the performance of this material,and material manufacturers do not have dedicated internal control standards for surgical implant materials,such as the Ti-6Al-4VELI high damage tolerance alloy standard commonly used by foreign surgical implant manufacturers,which has not yet been promoted and applied in China.

In the development of biomedical titanium and its alloys,Professor Wang Guisheng from Beijing Nonferrous Metals Research Institute,Professor Wei Shouyong from Baoji Nonferrous Metals Processing Plant,and Professor Li Zuochen from the Biomaterials Research Center of Northwest Nonferrous Metals Research Institute have done a lot of beneficial work and exploration.

In terms of the development of Ti-6Al-7Nb alloy,since 1996,it has been approved by the National Medical Administration.With the joint efforts of Beijing Nonferrous Metals Research Institute,Baoji Nonferrous Metals Processing Plant and their cooperative units,laboratory research and industrial trial production have been completed successively.Does the chemical composition and mechanical properties of the material fully comply with IS05832?According to regulation 11,the metallographic structure is equivalent to A4 level in the ETYC2(European Titanium Products Technical Committee)standard and complies with ISO5832?11 requirements for microstructure.In addition to small-scale trial investment,in 1999,Baoji Nonferrous Metal Processing Plant also exported more than ten tons of finished bar materials to the United States,earning hundreds of thousands of US dollars in foreign exchange.The material was appraised by experts in 2001,and this project also won the first prize of the China Nonferrous Metals Industry Science and Technology Award in 2001.

At present,the material is ready to be included in the revised version of the National Standard General Technical Conditions for Non active Surgical Implants for Bone Fusion(GBl2417).The national standard for Ti-6Al-7Nb rods for surgical implants is also being developed.

3.2 Existing problems

At present,although many implant manufacturers have made titanium alloy implants a focus of product development,the number of medical titanium is rapidly increasing(relative to themselves),there are still many misconceptions in China's medical titanium industry:implant manufacturers lack unified and high-quality internal control material standards,lack scientific understanding of material grades and properties,and blindly believe that all titanium is good,Multiple cases of implant rupture and failure in the body caused by product material reasons,leading to medical disputes:

Due to usage reasons,material manufacturers consider cost factors and only emphasize economic benefits,neglecting social benefits.Domestic material manufacturers have not yet produced titanium products for medical use,such as the Ti-6A1-4VELI alloy commonly used by European and American companies,including profiles,such as arc section panel strips,small diameter hollow thick wall pipes,joint forged thick plates,etc;

Due to various reasons,China's research and development efforts on titanium alloy materials for medical purposes are insufficient.The processing and surface treatment technology level of titanium alloy implanted products have a significant gap compared to advanced countries in the world;

Although the State Council has established the National Titanium Industry Management Office,due to the special nature of medical materials,China has not established a specialized branch or industry association responsible for or coordinating research and development,material standards,material quality control,product processing technology consulting,and exchange in the field of medical titanium,lacking unified industry management.

4.Outlook

(1)We should focus on developing biomedical titanium alloy materials with low elastic modulus,high wear resistance,corrosion resistance,high fracture toughness,low crack propagation rate,high damage tolerance,and excellent biocompatibility;

(2)The compatibility elements for alloy composition should be based on the premise of paying attention to the addition of non-toxic elements,such as mainly adding non-toxic"biological"metal elements such as Nb,Zr,Ta,Sn,Pt,etc;

(3)Efforts should be made to improve the quality level of biomedical titanium and its alloy processing materials in China.Manufacturers should pay attention to and meet the market demand for medical titanium,the quality control standards of materials should be in line with international standards,and the standardization work of materials should be strengthened;

(4)Efforts should be made to increase the development and research of materials,taking the path of joint development by material research institutes,universities,material production factories,medical research institutions,and clinical medical experts.This will integrate material research,biocompatibility testing,and clinical medical verification,accelerating the development of new biomedical titanium alloy materials with broad application prospects.

Author:He Baoming