DE19935935A1 - Hard fabric replacement material used e.g. as bone joint is produced from a titanium alloy containing zirconium - Google Patents

Abstract

Hard fabric replacement material is produced from a titanium alloy containing 0.01-10 wt.% zirconium.

Description

BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION

The invention relates to hard tissue replacement materials made from titanium alloys an additional material for a full or partial bone prosthesis for this or the like.

2. DESCRIPTION OF THE RELATED ART

Typically due to a higher compared to other metals Biocompatibility of the titanium an aluminum and vanadium-containing titanium alloy (Ti-6 wt .-% Al-4 wt .-% V) as a medical prosthesis, for example for bones and Tooth roots, used.

However, various studies report that vanadium is used in the above titanium alloy is toxic to human cells. It became a desirable (α + β) type titanium alloy for example a Ti-6% by weight Al-7% by weight Nb alloy, a Ti-5% by weight Al-2.5% by weight Fe- Alloy or a comparable alloy, tested by instead of vanadium Nb or Fe was added. Some studies report that aluminum in the Titanium alloy can cause dementia.  

Accordingly, titanium alloys of the β type were developed, in which metallic elements are used that are non-toxic and non-repellent and that are stretchable is higher than that of the (α + β) -type titanium alloy, very good cold workability and have a low modulus of elasticity, so that they are close to the biological hard tissue come.

The beta type titanium alloys include, for example, a Ti-13 wt% Nb-13 wt% Zr- Alloy, a Ti-16% by weight Nb-10% by weight Hf alloy, a Ti-15% by weight Mo- Alloy, a Ti-15% by weight Mo-5% by weight Zr-3% by weight Al alloy, a Ti-12 wt% Mo-6 wt% Zr-2 wt% Fe alloy, a Ti-i5 wt% Mo-2.8 wt% Nb-0.2 wt% Si-0.26 wt% O alloy or the like.

However, it has not been determined which component of a titanium alloy in these β-type titanium alloys are suitable for a hard tissue replacement material, as is the case for prostheses is used.

SUMMARY OF THE INVENTION

The aim of the invention is therefore to provide a hard tissue replacement material which is made from an alternative titanium alloy used for replacement materials of the Hard tissue of a living body is suitable and suitable strength, high Ductility, high wear resistance, a low modulus of elasticity and one possesses excellent corrosion resistance, so that it can react to the activities in one living body is adapted.

As a result of the inventors' serious studies on β-type titanium alloys To achieve the goal, the invention provides a hard tissue replacement material, wherein a Ti-Ta-Zr alloy made from titanium with fixed amounts of tantalum (Ta) and Zirconium (Zr) is made, or a Ti-Nb-Ta alloy, which is made of titanium with a specified amount of a mixture of niobium (Nb) and tantalum (Ta) and one previously  specified amount of one or more elements selected from molybdenum (Mo), Zirconium (Zr) and tin (Sn), was used.

One of the hard tissue replacement materials according to the invention is characterized in that that a titanium alloy is used which consists of 20 to 60 wt.% Ta, 0.01 to 10 wt.% Zr, remainder titanium and unavoidable impurities.

This achieves the aforementioned goal, so that hard tissue replacement material with suitable strength, high ductility, high wear resistance, low Elastic modulus and improved corrosion resistance can be realized, the Can adapt activities of a living body. The above hard tissue Replacement material is used to improve corrosion resistance and to maintain the β phase of the alloy structure Ta added. The Ta content is less than 20% by weight. so the β phase is not easy to manufacture. On the other hand, if the Ta content is 60% by weight exceeds, the melting point rises very sharply, so that no uniform Alloy structure is obtained and the workability suddenly deteriorates. Thus, the Ta content was set as the range described above. The more preferred range for the Ta content is between 40 and 60% by weight, the more uniform alloy structure of the β single phase is obtained. If 0.01% by weight or more Zr added, the mechanical properties improve, the Zr However, if the content exceeds 10% by weight, the alloy becomes brittle and the modulus of elasticity rises extremely, so the previously specified range is determined.

Another hard tissue replacement material according to the invention is the use of a Titanium alloy characterized, which consists of 20 to 60 wt .-% Nb and Ta together wherein one or more additives are selected from 0.01 to 10% by weight of Mo, 0.01 to 15 % By weight of Zr and 0.01 to 15% by weight of Sn, balance titanium and unavoidable impurities.

This can also be a hard tissue replacement material with suitable strength, high Ductility, high wear resistance and a low modulus of elasticity and a ver  produce better corrosion resistance that adapts to the activities of a living Body can adapt. It is desirable that the mixing range from Nb and Ta to a maximum of 50% by weight is sufficient.

The Nb content is preferably above 15% by weight to 50% by weight. Up to 15 wt% Nb the α phase separates from the alloy structure. The addition of more than 50% by weight Nb leads to insufficient ductility. Therefore, the Nb content is preferably maximum 45% by weight.

It is desirable that the Ta content be over 6% to 20% by weight. A salary of up to 6 wt.% Ta leads to insufficient ductility. If the Ta content is above 20 % By weight, a melting point of the alloy as such rises very sharply. Therefore is the maximum Ta content is preferably 15% by weight.

A selection of one or more of 0.01 to 10 wt% Mo, 0.01 to 15 wt% Zr and 0.01 to 15 wt.% Sn is the aforementioned titanium base alloy (Ti-Nb-Ta- Alloy) is added, whereby the titanium alloy is obtained with which the stabilization of the properties described here is achieved. The effects, like here before are limited and the costs increase if the additions to each Exceed the maximum value, therefore the above ranges are selected.

The invention includes the hard tissue replacement material for which a titanium alloy is used, the aforementioned titanium alloy with the addition of 0.01 to 0.5 wt .-% Palladium (Pd) is. Palladium is used to improve corrosion resistance and Biocompatibility. However, the effects described here cannot be obtained if the Pd content is less than 0.01% by weight and if it is more than 0.5% by weight increases, no complete solid solution state is reached, from which the above-mentioned salary range results. Regarding the homogeneity of the solid Solution state and effects is the more preferred range for the Pd content 0.1 wt% to 0.3 wt%.  

The invention includes the hard tissue replacement material in which the titanium alloy plastic deformation process with an area reduction of 95% or more experienced what caused the average crystal grain size of the resulting Alloy structure is 10 µm or less.

The crystal grain size in the alloy structure is set to 10 µm or less, whereby the hard tissue substitute material has the improved strength and wear resistance and the controlled ductility and the controlled elastic modulus. The area reduction (ratio of the cross-sectional reduction) is (1-A ₁ / A ₀ ) × 100%, where A _{0 stands} for the cross-sectional area before the plastic deformation process and A ₁ for the cross-sectional area after the plastic deformation process.

The invention also includes the hard tissue replacement material using the Titanium alloy used to recrystallize the crystal grains in the alloy structure Has experienced solution annealing. The hard tissue replacement material is also under Use of the titanium alloy included, which after solution annealing a Has undergone aging treatment.

The crystal grains can be removed by solution annealing and / or the aging treatment refine the beta phase in the titanium alloy, increase the strength accordingly and the Design ductility and the modulus of elasticity moderately.

Consequently, if hard tissue replacement materials can be used as a bone prosthesis, tooth root or Components that are used for dentures, an artificial limb or leg Effects and properties to adapt to the activities of a living body be obtained, which results in a contribution to the improvement of medical technology.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic flow diagram showing the processes for obtaining the hard tissue replacement material of the invention.

The Fig. 2 (A) and 2 (B) are a plan view and a side plan view of a tensile test specimen from the titanium alloys of the examples and of comparative alloys.

Fig. 3 is a graph showing the relationship between hardness and processing time at an aging treatment for any titanium alloy of the Examples.

Fig. 4 is a bar graph showing the tensile strength of the examples and the comparative examples.

Fig. 5 is a bar chart showing the ductility of the examples and comparative examples.

Fig. 6 is a bar chart showing the elastic modulus of the examples and comparative examples.

Fig. 7 (A) is a schematic view showing the shape of a tester for testing wear resistance, and Fig. 7 (B) is a bar graph showing the wear resistance of the examples and the comparative examples;

Figs. 8 (A) to 8 (E) are schematic views showing the corresponding manufacturing processes for obtaining the samples for the examples; and

Figure 9 is a bar graph showing the tensile strength and associated data of the examples and comparative examples shown in Figure 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT (DE)

The preferred embodiment of the invention will now be described by way of examples described in detail.

Titanium alloys of various compositions, in which titanium as a base with Nb and Ta is combined with a biocompatibility as high as titanium and with addition of one of Mo, Zr and Sn are melted. Titanium alloys made of titanium with Ta and Zr are made, and the Ti-Ta-Zr alloys are added with the addition of Pd also melted. These alloys are used to obtain button blanks from poured into molds of a certain size.

After each ingot has undergone a specified refrigeration process, as shown in FIG. 1, the treated material is cut into the required number of thin plates. The thin plates undergo a predetermined solution heat treatment and / or an aging treatment before they become a test specimen 1 having the required shape and size as shown in Fig. 2, molded and a tensile test and the like can be performed.

According to exactly the same processes from melting to solution annealing as in FIG. 1 and after the shaping as in test specimen 1 with the same size as in FIG. 2, the (α + β) -type titanium alloys and those known from the prior art are used β-type titanium alloys performed the tensile test and comparable tests.

With another cut from the same rough block described above The wear resistance of the titanium alloy is tested with a test specimen Wear resistance tester measured, which is explained in detail below.  

In the meantime, the titanium alloy having the same composition as described here before is melted to obtain a ingot having a practical size for use. The raw block obtained undergoes a plastic deformation process with a reduction in area of 95% or more, as described hereinafter. Solution annealing is then carried out on the ingot. A test specimen 1 with the same size as described here is obtained from the ingot. The tensile test is then carried out with the test specimen 1 .

Example A

The above description is based on specific examples and Comparative examples explained.

Titanium alloys with various compositions shown in Table 1 in which Titanium is combined with Nb and Ta, with high biocompatibility and then one of Mo, Zr and Sn has been added are melted. Even the titanium alloys with the compositions shown in Table 1 containing titanium with Ta and Zr, and the titanium alloys with Pd addition shown in Table 1 are melted.

As a comparative example, a Ti-6 wt% Al-4 wt% V- (α + β-type) alloy and a comparable alloy and a Ti-13 wt% Nb-13 wt% Zr (β-type) alloy and a comparable alloy shown in Table 1 melted.  

Table 1

The above titanium alloys are each poured into a predetermined mold a raw button block with a diameter of 30 mm, a thickness of 10 mm and to get a weight of 45 g. Each raw ingot is cold rolled (with one Reduction ratio of about 80%), being a rolled plate with fine crystal grains is obtained in the construction of any alloy.

Each rolled plate from each alloy is cut into 10 thin sheets.

Under the condition shown in Table 1, all of the metal sheets undergo solution annealing (ST) with recrystallization of crystal grains with a diameter of approximately 10 μm to approximately 50 μm. In addition, 5 trays undergo an aging treatment (STA) (see FIG. 1). However, in the alloy of Example 27, all 10 sheets are subjected to solution annealing (ST) and aging treatment (STA).

The reason for performing the three hour or longer aging treatment (STA) in Table 1 is that, as shown in a graph in Fig. 3, stable hardness is achieved by continuing the aging treatment for more than 3 hours while the Aging treatment for less than 3 h leads to unstable hardness.

Finally, each sheet is processed into a tensile test specimen 1 , as shown in FIG. 2. To measure tensile strength (σ _B / MPA), 0.2% yield strength, ductility (%) and elastic modulus (GPa), a tensile test was carried out with each sheet in accordance with JIS, Z2241.

The measurement results (mean values) are listed in Table 2.

Table 2

For easier recognition of the results in Table 2, the tensile strength, ductility and modulus of elasticity of Examples 5, 6, 9, 10, 17, 18, 25 and 26 and of Comparative Examples 1 to 6 are shown in the graphical illustrations in FIGS. 4 to 6 . The 0.2% yield strength shows a similar trend to the tensile strength in Fig. 4, so the graphical representation thereof has been omitted.

All ST materials (Examples 5, 9, 17 and 25) that are only subjected to solution heat treatment have a ductility 20% or more higher than Comparative Examples 1 to 4 (see Fig. 5), while the tensile strength and elasticity of this value show lower values than the comparative examples 1 to 6 (see FIGS. 4 and 6). In the case of an alloy having a high tensile strength and a high elastic modulus as shown in Comparative Examples 1 to 6, the alloy applied to a part of a living body may wear out or damage the surface of the bone or the like with which it is in contact. The modulus of elasticity of the bone is approximately 30 GPa. Therefore, the biocompatibility increases when the elastic modulus of an alloy approaches the value.

According to the results, each ST material of the titanium alloy in the examples has one sufficient ductility and lower strength and lower Modulus of elasticity than any comparative example, what the hard tissue of a living Body reaches. Therefore, if, for example, the material is in one part Bone fracture is implanted, the material integrally in accordance with the Formation of the bone shaped and thus allows long-term use as part of the Bone.

Each of the STA materials (Examples 6, 10, 18 and 26) that undergo the aging treatment has a tensile strength that is higher than that of the ST material of the same composition as the STA material. The STA materials with the exception of Examples 6 and 26 have tensile strengths which are lower than that of Comparative Examples 1 to 6 (see FIG. 4).

The ductility of each STA material is less than that of the ST material of the same composition. However, with the exception of Example 6, the STA materials have a ductility (above 10%) which corresponds to that of Comparative Examples 1 to 6 (see FIG. 5). With regard to the modulus of elasticity, the examples with the exception of examples 6 and 26 show values which are lower than those of the comparative examples (see FIG. 6).

The results show that each of the titanium alloys of the examples manufactured STA material has a high biocompatibility for hard tissue, the relative seen harder than the hard tissue to which the ST material is applied.

It should be mentioned that the alloy of Example 27 has the same composition like the alloys of Examples 9 and 10 of aging treatment for several hours after solution annealing, which improves tensile strength, 0.2% yield strength and modulus of elasticity. It is believed that this is on the Increase in hardness based.

From the results mentioned above it can be seen that the inventive Titanium alloys have different properties in order to get through solution annealing and / or the aging treatment easily to different hard tissues in one living Body adapt.

It is noteworthy that the solution annealing is carried out at temperatures in the range from 800 ° C to 1000 ° C for about 30 to about 60 minutes to obtain more refined and recrystallized crystals is desired. Furthermore, the aging treatment Maintaining temperatures from 400 ° C to 500 ° C for at least 2 hours or longer desirable to achieve the aforementioned hardness and strength, with the maximum duration maintaining the temperature is approximately 500 hours.

Then, using a tester 2 for wear resistance testing, as shown in Fig. 7 (A), the wear resistance of each titanium alloy of the examples and comparative examples is measured. In test apparatus 2, a test piece 1 a, consisting of the aforesaid button blank is in each case mm on a side length of 15 and a thickness of 2 mm is cut, immersed in Ringer's solution 3 at about body temperature (about 37 ° C) is held, and is rotated in a vessel 4 on a turntable 5 (60 rpm). A ball 6 made of zirconium oxide (ZrO ₂ ) is pressed onto the surface of test specimen 1 a with a load of 200 g. On the surface of Specimen 1 a of the turntable 5 mm forms a friction point with a radius of 5 in turning. The ball 6 is firmly attached to the lower end of a vertical element 7 , and a weight 9 lies on a shell 8 attached to the upper end of element 7 for the purpose of applying a load.

As shown in FIG. 7 (A), the vertical member 7 is fixed to the left end of a horizontal arm 10 . The arm 10 is supported and oscillates approximately from the center thereof around a lever support 11 of a peg 12 standing upright on a base 13 . The right end of arm 10 carries the annular weights 14 and 15 to compensate for the weight 9 .

With respect to each test specimen 1 a of the titanium alloys of Examples 3, 5, 9, 13, 15, 17 and 25 and of the titanium alloy of Comparative Example 1 was caused by the friction with the ball 6 weight reduction rate of the pressure of the Ball 6 originates on the test specimen 1 for a predetermined time, or the expansions of the friction point caused by the friction with the ball 6 are measured.

Fig. 7 (B) shows the results. As shown in the graph of FIG. 7 (B), the weight reduction rate and the expansion of the friction point were smaller and smaller than in Comparative Example 1 in each example.

Because each titanium alloy of the examples has one even when used in a living body People or the like have sufficient wear resistance and a stable long according to the results, their original structure, their original dimensions, their required strength and the like at a Long-term use as a hard tissue replacement material for an artificial joint, a Dentures and the like can be maintained.

Example B

A titanium alloy of the same composition as of Example 9 in Table 1 is melted and, mm by casting to a practically formed blank 1 G having a diameter of 60 and a weight of 60 kg, shaped as shown in Fig. 8 (A). This blank is subsequently mm at approximately 950 ° C to a columnar rod having a diameter of 1 B 40 as shown in Fig. 8 (B), hot forged (a plastic deformation process). This will continue mm at about 840 ° C to form a rod 1 B, having a diameter of 20, as in Fig. 8 (C), hot-forged. The bar 1 B 'is cold rolled into a flat plate 1 P as shown in Fig. 8 (D). The dimensions of the plate 1 P are 35 mm wide and 25 mm thick. Therefore, the cross section of plate 1 P (87.5 mm ² ) is approximately 3% of the cross section of blank 1 G (2826 mm ² ), the area reduction between plate 1 P and blank 1 G being approximately 97%.

After a plurality of plates 1 P have been subjected to solution annealing at 840 ° C. for 3 hours or at 760 ° C. for 3 hours, their surfaces are polished and they are punched around the previously determined test specimens 1 , corresponding to FIG. 2 (see Fig. 8 (E)). A test specimen 1 with which solution annealing is carried out at 840 ° C. is defined as example 28, and a test specimen 1 with which solution annealing is carried out at 760 ° C. is defined as example 29. In addition, the plate 1 P, with which solution annealing is not carried out, is polished and punched in order to obtain a further test specimen 1 , which is defined as Example 30. The tensile strength, the 0.2% yield strength and the ductility or the modulus of elasticity are measured in accordance with Example A with all test specimens 1 . Fig. 9 shows the results. In Fig. 9, the measured values obtained in Example 9 and Comparative Example 1 are given again.

According to the graph in FIG. 9, the tensile strength, the 0.2% yield strength and the modulus of elasticity of Examples 28 and 29 are higher than those of Example 9, but the ductility of Examples 28 and 29 decreases. Example 30 clearly shows this tendency. The ductility of all examples is over 10%, which is a value required for biocompatibility. The performance of the solution annealing and the like after the plastic deformation process is confirmed by the results.

Note that when observing the microstructure of each example with a Metallographers the average particle size of Example 28 and 29 6 microns and 5 µm was, while the average particle size of Example 9 was 25 µm and the average particle size of Example 30 was 9 µm. This can be due to this be attributed to the fact that the crystal grains by the plastic deformation process with a range reduction of approximately 97% or by solution annealing and that plastic deformation process with an area reduction of approximately 97% less than 10 µm were refined. Examples 28 to 30 each have the Young's modulus, which is smaller than the Young's modulus of Comparative Example 1. Thus it is obvious that the aforementioned alloys adhere to the living without problems Adjust body.

The invention is not intended to relate to the aforementioned embodiments and examples restrict.

For example, it is clear that the alloys of Examples 28 and 29 are the others have improved properties when they are aged after solution annealing be suspended.

The aforementioned titanium alloys can have two or more elements selected from Mo, Zr and Sn can be added. However, it is desirable that the overall The amount added in terms of cost benefit is 20% by weight or less.

It should be mentioned that that made from the titanium alloy of the present invention Hard tissue replacement material, aside from the aforementioned uses Implant materials, as a replacement for various hard tissues such as an artificial joint and as an orthodontic material or as additional materials to the replacement material can be used.  

With the hard tissue replacement materials according to the invention, as described here above can use titanium alloys with sufficient strength, high Ductility, high wear resistance and low modulus of elasticity using materials lower toxicity and rejection are provided which are required to adapt to the Hard tissues in a living body have satisfactory properties so that because of their biological compatibility they are suitable for long-term use.

Claims (18)

1. hard tissue replacement material made using a titanium alloy, consisting of 20 to 60 wt .-% tantalum, 0.01 to 10 wt .-% zirconium, balance titanium and inevitable impurities. 2. hard tissue replacement material according to claim 1, characterized in that the amount of tantalum added is 40 to 60% by weight. 3. hard tissue replacement material made using a titanium alloy, consisting of 20 to 60 wt .-% niobium and tantalum together, one or more Additives selected from 0.01 to 10% by weight of molybdenum, 0.01 to 15% by weight Zirconium and 0.01 to 15 wt .-% tin, balance titanium and unavoidable Impurities. 4. hard tissue replacement material according to claim 1, characterized in that the Titanium alloy contains 0.01 to 0.05 wt .-% palladium. 5. hard tissue replacement material according to claim 3, characterized in that the Titanium alloy contains 0.01 to 0.5 wt .-% palladium. 6. hard tissue replacement material according to claim 3, characterized in that the Mixing range of Nb and Ta ranges up to a maximum of 50% by weight. 7. hard tissue replacement material according to claim 3, characterized in that the amount of niobium is above 15% by weight to 50% by weight.   8. hard tissue replacement material according to claim 7, characterized in that the content of niobium is at most 45% by weight. 9. hard tissue replacement material according to claim 3, characterized in that the content of tantalum is over 6 to 20% by weight. 10. hard tissue replacement material according to claim 9, characterized in that the content of tantalum is a maximum of 15% by weight. 11. hard tissue replacement material according to claim 4, characterized in that the content of palladium is 0.1% by weight to 0.3% by weight. 12. hard tissue replacement material according to claim 5, characterized in that the content of palladium is 0.1 to 0.3% by weight. 13. hard tissue replacement material according to claim 1, characterized in that the Titanium alloy a plastic deformation process with an area reduction of 95% or more, which means that the average crystal grain size of the resulting alloy structure is 10 µm or less. 14. hard tissue replacement material according to claim 3, characterized in that the Titanium alloy a plastic deformation process with an area reduction of 95% or more, which means that the average crystal grain size of the resulting alloy structure is 10 µm or less.   15. hard tissue replacement material according to claim 1, characterized in that the Titanium alloy solution annealing for recrystallization of the crystal grain in the Alloy structure. 16. hard tissue replacement material according to claim 3, characterized in that the Titanium alloy solution annealing for recrystallization of the crystal grain in the alloy structure has gone through. 17. hard tissue replacement material according to claim 15, characterized in that the Titanium alloy subjected to aging treatment after solution annealing has been. 18. hard tissue replacement material according to claim 16, characterized in that the Titanium alloy subjected to aging treatment after solution annealing has been.