JPH0622575B2 - Bioremediation base material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to artificial joints, artificial dental roots, bone-joining members, artificial bones, etc. which are implanted in a living body in the medical fields such as dentistry and surgery. The present invention relates to an implant or orthodontic wire, a denture base, a structural member such as an orthopedic artificial limb, a artificial leg, and the like ...

(Prior Art) Conventionally, various materials such as an organic material-based material, an inorganic material-based material, and a metal-based material have been developed and used as the above-mentioned biological repair base material. These known materials are properly used depending on the site to be treated, but the properties required for a bioremediation base material are generally excellent in biocompatibility, non-toxic to living organisms, mechanically strong, and processed. What is good is desired.

Therefore, although ceramics and the like were the mainstream at the beginning of development, metal-based materials having excellent mechanical strength and workability have come to the forefront.

Typical metal type is stainless steel, Co-C
R-based alloys, pure titanium or titanium-based alloys, Ni-Ti alloys (shape memory alloys), etc. have been put to practical use.

(Problems to be Solved by the Invention) Conventionally known stainless steels and Co-Cr alloys have excellent mechanical strength and workability, but have problems in biocompatibility and biotoxicity (corrosion resistance in vivo). I have left.

In order to solve such a problem, a titanium-based alloy, in particular, an alloy consisting of 6Al-4V-residual Ti has been proposed and partially put into practical use, but it has excellent mechanical strength, but it has workability. However, some experts are concerned that vanadium, which is an alloy component, is toxic and that it is dissolved in the living body.

Further, Ni-Ti alloys (shape memory alloys), which have recently been attracting attention, are expected to be used in the future due to their peculiarities, but they have poor workability and nickel, which is an alloy component, gives the living body The issue remains that the impact cannot be ignored.

In particular, so-called biomedical implants such as artificial joints, osteosynthesis members, and artificial bones are required to have various shapes because they are used in the living body. Therefore, processing steps such as mechanical cutting, casting and forging are required. In particular, the more complicated the shape, the more products are processed through many processing steps. As the processing history increases, the properties of the base material are impaired and deteriorated and weakened. For example, 6Al-4, which is said to have the best mechanical strength among the above-mentioned metallic materials.
In the case of the V-residual Ti alloy, since the elongation of the material is small, heat treatment is required every time one working process is completed. If this heat treatment is omitted and the next processing step is started, defective products such as cracks and dimensional defects are likely to occur. Therefore, structural members such as orthodontic wires, denture bases, bone joint plates, artificial limbs, and artificial legs, which are processed and commercialized without being repeatedly subjected to heat treatment, have the above-mentioned defects and become impractical. Further, the more complicated the shape is, the more the number of processing steps is increased, and at the same time, the number of heat treatment steps is also increased, which significantly increases the processing cost. However, their excellent mechanical strength is difficult to throw away, and at present, they are used in artificial crotch joints, artificial tooth roots, etc., while leaving various problems. Pure titanium is not harmful to living organisms and is excellent in terms of biocompatibility, but it has a drawback that mechanical strength is significantly inferior to the above 6Al-4V-residual Ti alloy. Consideration of cross-sectional shape and avoiding stress concentration was essential for product manufacturing.

(Means for Solving the Problems) The present inventors have a high strength (65 kgf / mm ² or more) and an excellent elongation (10% or more), and a high tension thick plate, a high tension bolt, an anchor bolt, or the like. We have developed a Ti-Fe-based low alloy with increased suitability for titanium materials in the industrial field (Japanese Patent Application No. 63-197852). This product has Fe 0.1 to 0.
8% by weight, oxygen equivalent value Q = 0.35 to 1.0 = [O]
+2.77 [N] +0.1 [Fe] The balance is Ti except for unavoidable impurities, and the structure has α + β bi-phase equiaxed phase or lamellar phase-like fine grain structure. Although it is not applied, it has the above-mentioned high strength and ductility, but by the research and experiment after that, it is confirmed that this preceding low alloy is compatible with the above-mentioned desired properties of the biological repair base material. Came to know. That is, the present invention has a mechanical strength (tensile strength of 91 kg / mm ² or more, yield strength of 84 kg) comparable to that of 6Al-4V-remaining Ti, while maintaining the characteristics that pure titanium has no biotoxicity and is excellent in biocompatibility. / Mm ²
As described above, a base material for biological repair having a yield ratio of 0.92) has been found and provided here.

That is, the present invention contains 0.1 to 0.8% by weight of Fe, contains 0.01 to 0.10% by weight of N as a solid solution element, and O.
0.01 to 0.5% by weight, the balance is T except for unavoidable impurities
The present invention relates to a biorepair base material comprising a Ti-Fe-based low alloy base material made of i.

(Function) Fe in the present invention is a partial substitution type of Ti, and β
As an impurity element called eutectoid type, it acts to reduce the grain size of Ti crystals and contributes to high strength. That is, Fe is the maximum solid solubility limit in the α phase of about 0.06 wt% (hereinafter simply referred to as 0
%) And 0.1 to 0.8 wt% must be included. If it is less than 0.1%, the grain size of the Ti crystal is insufficient. On the contrary, if it exceeds 0.8%, the Ti crystal becomes coarse and a stable structure cannot be obtained, and the mechanical properties are deteriorated. N and O are both interstitial solid solution elements and are effective for strengthening the solid solution, but if they are excessive, ductility is lowered, which is not preferable. If N is 0.01 to 0.10% and less than 0.01%, the desired effect cannot be obtained, and if it exceeds 0.10%, it is excessively hardened to lower the mechanical strength. On the other hand, O is 0.1
When it is 0.5% and less than 0.1%, the desired effect is not exhibited like N, and when it exceeds 0.5%, the workability is deteriorated.

The Fe content in the above range has a correlation that prevents the decrease in ductility due to the N and O contents in the above range (particularly in the high content range) by refining the Ti crystals. A preferable range is 0.5% of Fe, 0.07% of N, and 0.2% of O, and the balance is Ti except for unavoidable impurities.

The structure adjustment in the low alloy of the present invention will be described.

The crystal grain size of the macrostructure of titanium ingot is about several tens of millimeters, so this is taken as the initial grain size and first heated above the β transformation point to refine the grain by transformation, and in the β single phase region, or β Hot working is performed from the zone to the α zone. In the case of the base material of the present invention, Fe is contained in the range of 0.1 to 0.8 wt% as described above, and further, in order to uniformly disperse Fe, by subjecting it to hot working in the β phase region, The unrecrystallized or recrystallized β phase changes into α + β two-phase lamellar phase-like fine grain structure during β → α transformation. Even if the structure is subsequently subjected to heat deformation processing again in the β single phase region, β to α phase region, or α single phase region, α + β two-phase lamellar phase or equiaxed fine phase It has a grain structure and is stable against thermomechanical treatment. Therefore, when hot-forming the ingot of the base material of the present invention by forging or rolling, at least once or more,
It is necessary to heat the ingot to the β region and perform hot working. According to this method, as is usually done, after hot working α
Even if post-heat treatment is performed in the region, a remarkable change in structure such as coarsening of crystal grains is unlikely to occur, and as a result, stable mechanical properties can be obtained.

Unlike the method described above, when the ingot is always heat-formed in the α region without being heated to the β region even once, the ingot macro has a rough surface, wrinkles, and a macro of Fe concentration. Segregation cannot be eliminated.

Therefore, in the case of hot forming by forging or rolling, the above-mentioned structure adjustment is necessary. However, when the cold forming can be done depending on the desired properties and shape of the implant member to be used, such structure adjustment is not necessary intentionally.

(Examples) The mechanical properties of the low alloy titanium, pure titanium (corresponding to two kinds), and 6Al-4V titanium alloy of the present invention are shown below.

Below, each example when applied to an artificial tooth root is shown.

As is clear from the above table, the Ti—Fe-based low alloy that is the base material for bioremediation of the present invention has mechanical properties close to the mechanical strength of the 6Al-4V titanium alloy, and further has improved elongation. It is understood that there is. It is also confirmed that the diameter of the rod-shaped artificial tooth root is slightly inferior to that of the 6Al-4V titanium alloy, but is smaller than that of pure titanium.

(Effects of the Invention) As will be apparent from the description, the base material for biological repair of the present invention is
Since it is made of a Ti low alloy with a small amount of Fe added to it, it is harmless to the human body, has excellent biocompatibility, and has excellent workability due to improved spreadability.
-Since it has a mechanical strength comparable to that of residual Ti alloy, it is not used for implanting in the above-mentioned dental implants, orthopedic implants, or other living bodies, but is repaired by being placed in an environment where the living body is in close contact with the living body. It has an effect that can contribute to an increase in suitability as a base material for use.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiromitsu Naito 5-10-1 Fuchinobe, Sagamihara City, Kanagawa Pref., 2nd Research Laboratory, Nippon Steel Corporation (72) Masayoshi Kondo 2 Otemachi, Chiyoda-ku, Tokyo ―6-3 Shin Nippon Steel Co., Ltd. (72) Inventor Naoshi Fukuyama 3-3-5 Chigasaki, Chigasaki City, Kanagawa Prefecture Toho Titanium Co., Ltd. (72) Inventor Masaaki Koizumi 3-3 Chigasaki City, Chigasaki City, Kanagawa Prefecture No. 5 Toho Titanium Co., Ltd. (72) Inventor Nobuo Fukada 3-3-5 Chigasaki, Chigasaki-shi, Kanagawa Toho Titanium Co., Ltd.

Claims (3)

[Claims] 1. A steel containing 0.1 to 0.8% by weight of Fe, and 0.01 to 0.10% by weight of N and O0.1 to 0.1% as solid solution elements.
A bioremediation substrate, characterized in that it is made of a Ti-Fe-based low alloy containing 0.5% by weight and the balance being Ti except for inevitable impurities. 2. 0.5% by weight of Fe, 0.07% by weight of N, O
The base material for biological repair according to claim 1, which is 0.2% by weight. 3. The biorepair base material according to claim 1, wherein the tissue comprises an α + β phase equiaxed phase-like or lamellar phase-like fine grain structure.