JP5633767B2 - Low elastic titanium alloy - Google Patents

Description

  The present invention relates to a low-elasticity titanium alloy that is not harmful to living organisms, is composed of abundant metal elements, and has an extremely small Young's modulus as an implant material such as an artificial bone or an artificial tooth root.

  With the arrival of an aging society and the development of medical treatment, it is predicted that the demand for implant materials such as artificial bones and artificial tooth roots will increase further in the future.

  Titanium has excellent corrosion resistance, is light and high in strength, and has good biocompatibility such as not causing allergies. From this point of view, titanium and titanium alloys are used for medical devices such as accessories, artificial bones, and implant materials that directly touch the skin, in addition to applications such as conventional corrosion-resistant machine parts and aircraft parts. It is being done.

  Titanium alloys are roughly classified into α (dense hexagonal crystal: hcp) type, β (body-centered cubic crystal: bcc) type, and α + β type from the crystal structure of the phase constituting the metal structure at room temperature. An alloy to which a small amount of industrial pure titanium or Al is added is α type, and Ti-6 mass% Al-4 mass% V alloy, which is well known as a high-strength alloy and used for aircraft, is α + β type, and this α + β type An alloy that further increases the element that stabilizes the β phase (β stabilizing element) is the β type.

  Among these, the β-type titanium alloy is considered as a promising material as an implant material because it has high elongation, excellent cold workability, and low elasticity depending on the composition (see Non-Patent Document 1). reference). As conventional β-type titanium alloys for living bodies, titanium alloys mainly composed of Ti and an open type β-stabilizing element (Nb, Ta, V, Mo, W, etc.) have been proposed (Patent Document 1 and 2). However, open β-stabilizing elements such as Nb and Ta are metal elements that are expensive and have a small amount of resources, and are difficult to apply to inexpensive implant materials for mass production. For example, in the titanium alloy of Patent Document 1, it is necessary to include the Nb and Ta in a total of 20 mass% to 60 mass%. Moreover, in patent document 2, it is necessary to contain about 25 mass%-40 mass% (in the illustrated test result, 35 mass%) of Nb of the main component.

  In order to adapt the titanium alloy to the implant material, it is necessary to have mechanical properties, particularly a low elastic modulus. This is because the Young's modulus of human bone is 10 to 30 GPa, whereas the Young's modulus of pure Ti, which is considered to have a low elastic modulus among metals, is about 110 GPa. Thus, the elastic modulus of bone is greatly different. In addition, when bone is broken due to elastic strain generated at the interface between human bone and implant material, or when only the implant material is loaded, bone resorption occurs because the bone does not function sufficiently There is a fear.

  In addition, the implant material has an adhesive property that can be stably used in vivo over a long period of time (for example, an adhesive property to bone) and an exfoliation property that can be easily removed and recovered after the biological tissue is treated and repaired. Therefore, it is desired to appropriately exhibit contradictory characteristics. Ti is highly adaptable to living bodies, but has strong adhesiveness to bones, and there are cases in which adverse effects are pointed out. On the other hand, Zr, which is not harmful to living organisms like Ti, is said to have poor adhesion to living organisms, and by replacing part of Ti with Zr, there is a possibility of becoming an implant material with moderate adhesiveness. There is also a need for such implant materials.

  The optimal range of the elastic modulus (and further strength and adhesiveness) of the implant material varies depending on the body type, case, or application site of the patient to be treated, and so-called custom-made implant materials are required. Therefore, it is composed of elements and compositions that satisfy all the functions of (1) low-elasticity alloy, (2) safety to the human body, (3) inexpensive and abundant resources, and (4) moderate strength and adhesion. A titanium alloy is desirable.

  Therefore, the present inventor paid attention to Cr, which is a eutectoid β-stabilizing element that is inexpensive and has a large amount of resources without using an open β-stabilizing element as a β-stabilizing element, and Ti—Cr added with Sn or the like. We have been researching titanium alloys. As disclosed in Non-Patent Document 2, it has been clarified that a metastable β phase exhibits low elasticity even in a Ti—Cr titanium alloy as in the case of a Ti—Nb system.

Japanese Patent Laid-Open No. 10-219375 JP 2006-274319 A

X. TANG, (Tea Ahmed) AHMED, H.J. J. et al. RACK, "Phase transformations in Ti-Nb-Ta and Ti-Nb-Ta-Zr alloys", Journal of Materials Science (JOURNAL OF MATERIALS SCIENCE), Kluwer Academic Publishers, 35 (2000), p. 1805-1811 Yonosuke Murayama (Y. Murayama) and 5 others, “Mechanical Properties and Phase Stability of Ti-Cr System Alloys”, TMS: TMS Metals & Materials Society), February 2009, Volume 3, pages 263-270.

  Therefore, the present invention has been made in view of the above circumstances, and is made of a cheap and resource-rich metal element that is not toxic to the living body, has sufficient strength as an implant material, and is close to a low elasticity human bone. An object is to provide a low-elasticity titanium alloy having a Young's modulus.

  Another object of the present invention is to provide an optimal metal composition and composition range in which the Young's modulus is minimized in the low elastic titanium alloy.

  Another object of the present invention is to provide a low-elasticity implant material or a treatment device in which a part of Ti is replaced with Zr to a high composition range in consideration of adhesiveness.

  The titanium alloy of the present invention is a Ti—Cr—Sn ternary alloy, a Ti—Cr—Sn—Zr quaternary alloy, or a Ti—Cr—Al ternary alloy, and has a low elasticity with a Young's modulus of less than 70 GPa. Specifically, it has the following alloy composition.

(Embodiment 1: Preferred alloy composition of Ti—Cr—Sn alloy)
1. A titanium alloy containing, in mass%, Cr in a range of 4.0% to 7.0%, Sn in a range of 2.0% to 10.0%, and the balance being Ti and inevitable impurities.
2. A titanium alloy containing, in mass%, Cr in a range of 2.0% to less than 4.0%, Sn in a range of 5.0% to 10.0%, and the balance being Ti and inevitable impurities.
3. A titanium alloy containing, in mass%, Cr in a range greater than 7.0% and 9.0% or less, Sn in a range of 5.0% to 10.0%, and the balance being Ti and inevitable impurities.

(Embodiment 2: Preferred alloy composition of Ti—Cr—Sn—Zr alloy)
4). In mass%, Cr is contained in the range of 4.0% to 7.0%, Sn is 5.0% to 10.0%, Zr is 40% or less, and the balance is from Ti and inevitable impurities. Titanium alloy.
5. In mass%, Cr is contained in a range of 3.0% to less than 4.0%, Sn is contained in a range of 5.0% to 10.0%, Zr is greater than 5.0% and 40% or less, and the balance is Titanium alloy consisting of Ti and inevitable impurities.
6). Containing Cr in a range of 1.0% to less than 3.0%, Sn in a range of 5.0% to 10.0%, Zr in a range of 25% to 40%, the balance being Ti and inevitable Titanium alloy consisting of mechanical impurities.
7). In mass%, Cr is contained in a range of greater than 7.0% to 9.0% or less, Sn from 5.0% to 10.0%, Zr to 25% or less, the balance being Ti and inevitable impurities Titanium alloy consisting of

(Embodiment 3: Preferred alloy composition of Ti—Cr—Al alloy)
8). A titanium alloy containing, in mass%, Cr in a range of 7.0% to 12%, Al in a range of 2% to 7%, with the balance being Ti and inevitable impurities.

  According to the first aspect or the third aspect of the present invention, since the element is composed of Ti—Cr—Sn or Ti—Cr—Al, the constituent element is toxic to the living body as compared with the Ti—Nb titanium alloy. It is possible to provide a low-elasticity titanium alloy made of a metal element (Sn is slightly lower but still about twice Nb) that is inexpensive and has abundant resource reserves. Also, the amount of Cr, which is a β-stabilizing element, can be significantly smaller than the amount of Nb added in the Ti—Nb-based titanium alloy described above.

  According to the second aspect of the present invention, since the element is composed of Ti—Cr—Sn—Zr, only that the constituent element has no toxicity to the living body as compared with the Ti—Nb titanium alloy. In addition, it is possible to provide a low-elasticity alloy composed of metal elements rich in resource reserves. Although Zr is not necessarily inexpensive, it can be said that it is less expensive than the Ti—Nb system because the amount of Zr element added can be reduced in the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the titanium alloy provided with the optimal metal composition and composition range from which an elastic modulus becomes the minimum can be provided.

  Furthermore, according to the second aspect of the present invention, in the titanium alloy composed of Ti—Cr—Sn—Zr of the present invention, Ti and Cr are elements having good adhesion to bone tissue, and Zr is It is considered an element with low adhesion. By appropriately controlling the composition amount of these elements, there is a possibility of obtaining an alloy having appropriate adhesiveness, and it is possible to provide a custom-made treatment device or implant material suitable for the body shape, case and application site. . In these low elastic alloys, the Zr addition amount can be included in a large amount (10 mass% or more). For example, even if Zr is included in an amount of about 40 mass%, a sufficiently low Young's modulus can be maintained.

In the Ti—Cr—Sn titanium alloy, FIG. 1 (a) is a diagram showing the influence of the Cr addition amount and the Sn addition amount on the Young's modulus, and FIG. 1 (b) shows the Cr addition amount and the Sn addition amount. It is the figure which showed on the composition figure of Ti-Cr-Sn ternary system the influence which has on Young's modulus. It is the figure which showed the diffraction pattern by a transmission electron microscope (TEM) when an electron beam permeate | transmits perpendicularly | vertically to the (110) plane of a Ti-Cr-Sn titanium alloy beta phase, and the schematic diagram corresponding to it. is there. In the Ti—Cr-6 mass% Sn—Zr titanium alloy, FIG. 3 (a) is a diagram showing the influence of the Cr addition amount and the Zr addition amount on the Young's modulus, and FIG. 3 (b) shows the Cr addition amount. It is the figure which showed the influence which Zr addition amount has on Young's modulus on the composition figure (6 mass% Sn fixed) of a Ti-Cr-Zr ternary system. It is the figure which showed the influence which Cr addition amount and Al addition amount have on Young's modulus in a Ti-Cr-Al titanium alloy.

  Next, the composition of the titanium alloy according to the present invention, the reason for the structure control, and the production method thereof will be specifically described. In this specification, the alloy composition is expressed as “mass%”, that is, “mass%” unless otherwise specified. Further, in the figures and tables, for example, when expressed as Ti-8Cr-6Sn-10Zr, it is a titanium alloy containing Ti, Cr, Sn, and Zr, and the Cr content is 8% by mass, The Sn content is 6% by mass, the Zr content is 10% by mass, and the remainder is the content of Ti and inevitable impurities.

  The titanium alloy according to the present invention has a metastable β phase equiaxed structure or martensitic structure depending on the amount of Cr added. The crystal structure of titanium varies depending on the temperature, and becomes a crystal structure called body-centered cubic at high temperatures. This body-centered cubic crystal of titanium is also called a β phase, and as described above, titanium consisting only of the β phase is called a β-type titanium alloy. By adding a certain amount or more of a β-stabilizing element to pure titanium and quenching from a high temperature, an alloy consisting of only the β phase is obtained even at room temperature. Such a β-type titanium alloy cannot be present at room temperature, so it is called a metastable β-titanium alloy.

  Further, when the amount of β-stabilizing element does not reach a certain amount, a martensitic structure can be obtained by rapid cooling from a high temperature. In other words, the martensitic transformation temperature changes depending on the amount of β-stabilizing element, and the composition of the alloy changes from a martensitic structure to a metastable β-phase structure with a composition before and after the composition at which the martensitic transformation temperature is near room temperature. .

  In the titanium alloy of the present invention, in the Ti—Cr—Sn ternary alloy and Ti—Cr—Al ternary alloy, those with a Cr addition amount of less than 8 mass% all show a martensite structure, and the Cr addition amount is 8 mass% or more. Was a metastable β-phase structure. That is, an alloy having a very low Young's modulus with a composition near the transition composition from the martensite structure to the metastable β-phase structure was obtained.

  In the Ti—Cr—Sn—Zr quaternary alloy, all of the Cr addition amount of 8 mass% or more had a metastable β-phase structure, but the Cr addition amount of less than 8 mass% depends on the Zr addition amount. When the addition amount increases, the martensite structure shifts to a metastable β phase structure. Also in the Ti—Cr—Sn—Zr quaternary alloy, an alloy having an extremely low Young's modulus was obtained in the vicinity of the transition composition from the martensite structure to the metastable β-phase structure.

  The titanium alloy according to the present invention does not contain an open β-stabilizing element (Nb, V, Ta, W) that is usually included as a β-stabilizing element, but contains Cr and Sn (or Al). Moreover, the titanium alloy according to the present invention may further contain Zr.

  Here, Cr is called a eutectoid β-stabilizing element, and forms an intermetallic compound with Ti. Note that the open β-stabilizing element used as the main component of the titanium alloy in the above prior art is different in that it does not form an intermetallic compound with Ti. The eutectoid β-stabilizing element can obtain a metastable β-phase by rapid cooling from a high-temperature phase, and can obtain a β-phase with a much smaller amount of alloy addition than an open-type β-stabilizing element. Become.

  Further, when a β-stabilizing element is added to Ti, the martensite temperature gradually decreases. However, as described above, when the martensite transformation temperature is close to room temperature, a β single-phase material can be obtained. For example, when comparing compositions having a martensite transformation start temperature of 200 ° C., the open β-stabilizing elements V, Nb, Ta, Mo, W, etc. are 14 mass%, 33 Addition amounts of 0.3 mass%, 47.2 mass%, and 12.6 mass% are necessary, whereas Cr and Fe as eutectoid β-stabilizing elements are added in amounts of 6.5 mass% and 3.8 mass%. Just do it. That is, it can be said that the eutectoid β-stabilizing element has a higher ability as a β-stabilizing element and produces the same effect with a small addition amount.

  Note that Cr is not only toxic to living organisms like Nb and Ta, but is also a very inexpensive and abundant resource reserve.

  Sn, Al, and Zr are also said to be non-toxic to living organisms, but inclusion with elements such as Cr described above is expected to suppress the formation of the ω phase and further reduce the elastic modulus. The The ω phase is a hard and brittle intermetallic compound that is produced when a titanium alloy to which a β-stabilizing element is added in a certain composition range is rapidly cooled from a high temperature. To rise.

  The titanium alloy of the present invention may be produced using a non-consumable electrode type or a consumable electrode type vacuum or argon arc melting method, an electron beam melting method, a plasma melting method or the like that is usually used in the titanium alloy field. The obtained ingot is formed into a required shape by a generally used method such as hot forging or hot rolling.

  In this example, three types of production examples of (1) Ti—Cr—Sn alloy, (2) Ti—Cr—Sn—Zr alloy, and (3) Ti—Cr—Al alloy having low elasticity are shown. Details of the match gold composition and test results (Young's modulus and tensile strength) are shown in Tables 1 to 3. Here, Table 1 shows the details of the alloy composition and test results of the ternary titanium alloy (Ti-Cr-Sn), and Table 2 shows the alloy composition of the quaternary titanium alloy (Ti-Cr-6Sn-Zr) and Details of the test results are shown, and Table 3 shows details of the alloy composition and test results of another ternary titanium alloy (Ti-Cr-Al).

  In each table, a “judgment” column is provided, and an alloy composition having a Young's modulus result of 70 GPa or more is marked with “x” and “comparative example” in the “category” column. . On the other hand, an alloy composition having a Young's modulus result of 60 GPa or more and less than 70 GPa is marked with “◯”, and an alloy composition with a Young's modulus result of less than 60 GPa is marked with “◎”. Is "invention example" in the "category" column.

  In the production of match money, all are made of metal materials (Ti, Cr, Sn, Al, Zr) with a purity of 99% or more so that they have a desired composition and are non-consumable using tungsten electrodes. A button ingot of about 30 grams was prepared by an argon arc melting method. The button ingot was hot-rolled at 800 ° C. for about 80% to obtain a plate having a thickness of 1.5 to 2 mm. From this plate, a test piece for tensile test was cut out, this test piece was sealed in a quartz tube, heated to 950 ° C. in vacuum, held for 2 hours, and then put into ice water and quenched. Went. Such a heat treatment is called a solution treatment.

  Using this solution-treated material, a tensile test was performed to measure the elastic modulus, tensile strength, and elongation. The Young's modulus was calculated from the relationship between strain and stress at the time of constant load in two or three stages with a strain gauge attached to the surface of the tensile test piece. At this time, attention was paid so that the stress at a constant load did not exceed the yield strength from the stress-strain curve measured in advance. In calculating the Young's modulus, the strain gauge was replaced three times or more for at least one tensile test piece, and the reproducibility was confirmed by measuring using two or more test pieces.

  The evaluation results are summarized in Tables 1 to 3 and FIGS.

  In the Ti—Cr—Sn ternary titanium alloy, FIG. 1A is a diagram showing the influence of the Cr addition amount and the Sn addition amount on the Young's modulus. From FIG. 1 (a), it can be understood that the Young's modulus generally decreases as the amount of Sn added increases as the amount of Sn increases. Further, it can be seen that in any titanium alloy to which Sn is added, the Cr addition amount is the smallest in the range of 3.5 to 8 mass%, and there is a minimum point in the vicinity of 5 mass% Cr. It can be seen that the Young's modulus decreases significantly as the amount of Sn added is increased. This is because the addition of Sn effectively suppresses the generation of the ω phase, as will be described later.

  FIG. 1B is a diagram showing the influence of the Cr addition amount and the Sn addition amount on the Young's modulus on the composition diagram of the Ti—Cr—Sn ternary system. FIG. 1B shows the same data as the test results shown in FIG. 1A, with the Sn addition amount shown on the lower axis and the Cr addition amount on the left diagonal axis. The Young's modulus of the titanium alloy having the Cr addition amount and the Sn addition amount is shown at the intersection of the Cr value and the Sn value given on these axes. According to the Young's modulus diagram shown on the composition diagram of this Ti—Cr—Sn ternary system, the range in which Cr is about 5 mass% (4 mass% to 6 mass%) and Sn is 3 mass% to 9 mass% in mass%. It is understood that a titanium alloy having a very low Young's modulus of less than 55 GPa can be obtained by preparing a titanium alloy containing Ti and the balance of Ti and inevitable impurities.

  FIG. 2 shows a diffraction pattern by a transmission electron microscope (TEM) when an electron beam is transmitted perpendicular to the (110) plane of the Ti—Cr—Sn titanium alloy β phase, and a corresponding schematic diagram. FIG. Note that a spot pattern corresponding to the crystal structure can be observed in the TEM diffraction pattern. In an alloy in which the ω phase is mixed in the β phase, when an electron beam is transmitted perpendicularly to the (110) plane of the β phase, a schematic diagram (diagonal lines are attached to each TEM image in FIG. 2). As shown by two nested rectangles), spots derived from β-phase crystals (each corner point on the outside; indicated as “β-spot” in FIG. 2) at each corner of the large rectangle Spots derived from the ω phase (inner corner points; expressed as “ω spots” in FIG. 2) appear at the positions of the corners of the small rectangle existing inside the large rectangle. It can be seen that the phase structure of the spots shown in the schematic diagram is regularly arranged in the diffraction pattern of FIG.

  The image of the diffraction pattern shown in FIG. 2 is four types of Ti-8Cr, Ti-8Cr-3Sn, Ti-8Cr-6Sn, and Ti-8Cr-9Sn from the left, and only the Sn amount changes from zero to 9 mass%. doing. Comparing these figures, it can be seen that the intensity of the ω spot indicating the ω phase becomes weaker as the Sn addition amount increases (in the images of Ti-8Cr-6Sn and Ti-8Cr-9Sn, the ω spot is reduced). It can hardly be recognized). That is, it can be seen that when Sn is added to the Ti—Cr alloy generated by the ω phase, the generation of the ω phase is suppressed. Therefore, it can be seen that by increasing the Sn addition amount to some extent in the titanium alloy, the generation of the ω phase can be suppressed, and consequently the Young's modulus of the alloy can be reduced.

  FIG. 3A is a diagram showing the influence of the Cr addition amount and the Zr addition amount on the Young's modulus in the Ti—Cr-6 mass% Sn—Zr titanium alloy. In FIG. 3A, since it was desired to evaluate only the influence of Cr and Zr, the Sn addition amount is fixed to a fixed amount of 6 mass%. That is, the elastic modulus results in Table 2 are mainly plotted.

  In FIG. 3A, when a titanium alloy having a small Cr addition amount (2 mass% Cr, circled in the figure) is used, the Young's modulus decreases rapidly as the Zr addition amount is increased. I understand that. In particular, it can be seen that when the Zr addition amount is 30 mass% or more, the Young's modulus is less than 60 GPa. When the Cr addition amount is 3.5 mass% (square mark in the figure) or 5 mass% (diamond mark in the figure), the Young's modulus increases or decreases in the range of 45 to 70 GPa over the entire Zr addition amount range. repeat. Then, it can be seen that in an alloy having a large Cr addition amount (8 mass% Cr, a triangular mark in the figure), the Young's modulus gradually increases when the Zr addition amount is increased. For example, when the Zr addition amount is 30 mass% or more, the Young's modulus becomes a value of 70 GPa or more. Therefore, the Zr addition amount is preferably set to 25 mass% or less (more preferably 20 mass% or less).

  FIG. 3B shows the effect of the Cr addition amount and the Zr addition amount on the Young's modulus in the Ti—Cr—6 mass% Sn—Zr titanium alloy on the composition diagram of the Ti—Cr—Zr ternary system (6 mass%). It is the figure shown to Sn fixation. FIG. 3B is drawn by the same method as FIG. According to the Young's modulus diagram shown on the composition diagram of this Ti-Cr-Zr ternary system, in order to produce a titanium alloy having a low Young's modulus of less than 70 GPa, when Cr is around 2 mass%, Zr is It can be seen that the content is preferably in the range of 30 mass% or more and 40 mass% or less. Moreover, when Cr is around 3.5 mass%, it is preferable to contain Zr in the range which becomes 10 mass% or more and 40 mass% or less. Moreover, when Cr is around 5.0 mass%, it is preferable to contain Zr in the range used as 40 mass% or less. Furthermore, when Cr is about 8.0 mass%, it turns out that it is preferable to contain Zr in the range used as 20 mass% or less.

  FIG. 4 is a diagram showing the influence of the Cr addition amount and the Al addition amount on the Young's modulus in the Ti—Cr—Al titanium alloy. As can be seen from FIG. 4, in the titanium alloy having an Al addition amount of 3 mass% or 6 mass%, a local minimum point exists when the Cr addition amount is around 8 mass%. In addition, when the addition amount of Al is remarkably small (1.5 mass%) and when remarkably large (9.0 mass%), it turns out that the reduction effect of Young's modulus is not exhibited. From the above results, when Cr is around 8 mass% and around 11 mass%, it is preferable to contain Al in a range of 3 mass% to 6%.

  The measurement results of the strength are as shown in Tables 1 to 3, and the tensile strength of the titanium alloy of the present invention is in the range of about 700 to about 1100 MPa, and shows a sufficiently high value similarly to the strength of the comparative example. ing.

  From Tables 1 to 3 and FIGS. 1 to 4 described above, the titanium alloy, Ti—Cr—Sn alloy, Ti—Cr—Sn—Zr alloy, or Ti—Cr—Al alloy of the present invention has a composition. Thus, it can be seen that the Young's modulus is less than 70 GPa, and a titanium alloy having the following alloy composition is preferable.

(Preferable alloy composition of Ti-Cr-Sn alloy)
1. A titanium alloy containing, in mass%, Cr in a range of 4.0% to 7.0%, Sn in a range of 2.0% to 10.0%, and the balance being Ti and inevitable impurities.
2. A titanium alloy containing, in mass%, Cr in a range of 2.0% to less than 4.0%, Sn in a range of 5.0% to 10.0%, and the balance being Ti and inevitable impurities.
3. A titanium alloy containing, in mass%, Cr in a range greater than 7.0% and 9.0% or less, Sn in a range of 5.0% to 10.0%, and the balance being Ti and inevitable impurities.

(Preferable alloy composition of Ti—Cr—Sn—Zr alloy)
4). In mass%, Cr is contained in the range of 4.0% to 7.0%, Sn is 5.0% to 10.0%, Zr is 40% or less, and the balance is from Ti and inevitable impurities. Titanium alloy.
5. In mass%, Cr is contained in a range of 3.0% to less than 4.0%, Sn is contained in a range of 5.0% to 10.0%, Zr is greater than 5.0% and 40% or less, and the balance is Titanium alloy consisting of Ti and inevitable impurities.
6). Containing Cr in a range of 1.0% to less than 3.0%, Sn in a range of 5.0% to 10.0%, Zr in a range of 25% to 40%, the balance being Ti and inevitable Titanium alloy consisting of mechanical impurities.
7). In mass%, Cr is contained in a range of greater than 7.0% to 9.0% or less, Sn from 5.0% to 10.0%, Zr to 25% or less, the balance being Ti and inevitable impurities Titanium alloy consisting of

(Preferable alloy composition of Ti-Cr-Al alloy)
8). A titanium alloy containing, in mass%, Cr in a range of 7.0% to 12%, Al in a range of 2% to 7%, with the balance being Ti and inevitable impurities.

  The low-elasticity titanium alloy of the present invention is a promising alloy material that can be used as an implant material composed of a metal element that is not toxic to living bodies and has abundant resources, and has industrial applicability. In particular, Ti—Cr—Sn ternary alloys, Ti—Cr—Al ternary alloys, and Ti—Cr—Sn—Zr alloys with a small amount of Zr added are much cheaper than Ti—Nb low elasticity titanium alloys. It will be something. In addition, we have succeeded in reducing the elasticity of Ti-Cr-Sn-Zr quaternary alloys in which the composition ratio of Ti and Zr, which is considered to have different adhesion to bone tissue, has been greatly reduced. By producing a low-elasticity titanium alloy whose composition amount is appropriately controlled, it is considered that a custom-made treatment device and implant material optimal for the body shape, case, and application site can be provided.

Claims (3)

In a mass%, Cr is contained in a range of 4.0% to 6.0%, Sn is contained in a range of 5.0% to 9.0%, Zr is greater than 0% and 40% or less, and the balance is Ti and A low-elasticity titanium alloy for in vivo implants consisting of inevitable impurities,
The titanium alloy is applied to a bone of a living body, and
A low-elasticity titanium alloy for biological implants, wherein the titanium alloy has a Young's modulus of less than 60 GPa. Contains Cr in a range of 3.0% to less than 4.0%, Sn in a range of 5.0% to 9.0%, and Zr in a range of 10% to 30%, with the balance being Ti and inevitable Low-titanium titanium alloy for biological implants consisting of mechanical impurities,
The titanium alloy is applied to a bone of a living body, and
A low-elasticity titanium alloy for biological implants, wherein the titanium alloy has a Young's modulus of less than 60 GPa. Contains Cr in the range of 1.0% to less than 3.0%, Sn in the range of 5.0% to 9.0%, Zr in the range of 30% to 40%, the balance being Ti and inevitable Low-titanium titanium alloy for biological implants consisting of mechanical impurities,
The titanium alloy is applied to a bone of a living body, and
A low-elasticity titanium alloy for biological implants, wherein the titanium alloy has a Young's modulus of less than 60 GPa.