JP6922196B2 - Titanium sintered body, ornaments and heat resistant parts - Google Patents

Description

The present invention relates to titanium sintered bodies, ornaments and heat-resistant parts.

Titanium alloys are used in fields such as aircraft, space development, and chemical plants because of their excellent mechanical strength and corrosion resistance. Recently, taking advantage of the biocompatibility, low Young's modulus, lightweight, etc. of titanium alloy, it is being applied to exterior parts of wristwatches, ornaments such as eyeglass frames, sports equipment such as golf clubs, springs, etc. be.

Further, in such an application, by applying the powder metallurgy method, a titanium sintered body having a shape close to the final shape can be easily manufactured. As a result, the secondary processing can be omitted or the processing amount can be reduced, and efficient parts production becomes possible.

However, the titanium sintered body produced by the powder metallurgy method has low wear resistance. Therefore, when the titanium sintered body is applied to a sliding component, wear occurs as the titanium sintered body slides, and adhesion occurs with the mating member.

Therefore, Patent Document 1 includes an Fe-Ti phase having a Ti content of 30 to 80% by mass, a soft metal phase having corrosion resistance, and pores, and the Fe-Ti phase and the soft metal phase are dispersed in a patchy manner. Fe-Ti sintered members having a metal structure, having a soft metal phase in the entire structure of 5 to 20% by volume, and having a density ratio of 90% or more have been proposed. It is disclosed that such a Fe-Ti sintered member is suitable for a sliding member for a machine, an automobile, or the like.

Japanese Unexamined Patent Publication No. 2006-131950

However, since the Fe-Ti sintered member described in Patent Document 1 contains Fe in a relatively high concentration, it has lower corrosion resistance and a larger mass than pure titanium or a titanium alloy containing more than 80% of titanium. Moreover, since the Fe-Ti sintered member described in Patent Document 1 contains pores, the frictional resistance becomes large and the wear resistance is inferior. In addition, since the Fe—Ti sintered member contains Fe in a relatively high concentration, its mechanical strength is inferior to that of the titanium alloy.

An object of the present invention is to provide a titanium sintered body, an ornament, and a heat-resistant part having excellent wear resistance.

The above object is achieved by the following invention.
The titanium sintered body of the present invention is composed of a material containing titanium.
It contains the α phase and β phase of titanium as a crystal structure.
The area ratio occupied by the α phase in the cross section is 78 % or more and 99.8% or less.
The average particle size of the α phase in the cross section is 5 μm or more and 30 μm or less.
The oxygen content is 3200 ppm or more and 5500 ppm or less in terms of mass ratio.
The surface is characterized by having a Vickers hardness of 300 or more and 500 or less.

As a result, the corrosion resistance of the sliding surface is increased and the frictional resistance of the sliding surface is reduced, so that a titanium sintered body having excellent wear resistance can be obtained.

In the titanium sintered body of the present invention, the average aspect ratio of the α phase is preferably 1 or more and 3 or less.

In the titanium sintered body of the present invention, in the X-ray diffraction spectrum acquired by the X-ray diffraction method, the peak value of the reflection intensity due to the plane orientation (110) of the β phase depends on the plane orientation (100) of the α phase. It is preferably 5% or more and 60% or less of the peak value of the reflection intensity.

As a result, the characteristics of the α phase and the characteristics of the β phase become apparent without being buried. As a result, a titanium sintered body that can maintain excellent wear resistance for a particularly long period of time can be obtained.

The titanium sintered body of the present invention preferably contains particles containing titanium oxide as a main component.
As a result, the particles containing titanium oxide as a main component are dispersed in the titanium sintered body, and the stress applied to the metallic titanium as a matrix is shared. Therefore, by including the particles, the mechanical strength of the entire titanium sintered body can be improved.
In the titanium sintered body of the present invention, the average particle size of the particles is preferably 0.5 μm or more and 20 μm or less.

In the titanium sintered body of the present invention, the relative density is preferably 99% or more.
As a result, the vacancies are less likely to be exposed on the sliding surface, so that wear starting from the vacancies is less likely to occur, and the frictional resistance is reduced, so that a titanium sintered body exhibiting particularly good wear resistance can be obtained. Be done.

The ornament of the present invention is characterized by containing the titanium sintered body of the present invention.
As a result, the surface is provided with excellent wear resistance, and scratches and wear are suppressed, so that an ornament that can maintain an excellent aesthetic appearance for a long period of time can be obtained.

The heat-resistant component of the present invention is characterized by containing the titanium sintered body of the present invention.
As a result, heat-resistant parts having excellent wear resistance and heat resistance can be obtained.

It is an electron microscope image which shows the embodiment of the titanium sintered body of this invention. It is a figure which drew a part of the electron microscope image shown in FIG. 1 schematically. It is a perspective view which shows the timepiece case to which the embodiment of the ornament of this invention is applied. It is a partial cross-sectional perspective view which shows the bezel to which the embodiment of the ornament of this invention is applied. It is an X-ray diffraction spectrum obtained about the titanium sintered body of Example 1. It is a side view which shows the nozzle vane for a turbocharger to which the 1st Embodiment of the heat-resistant component of this invention was applied (the figure when the wing part is viewed in a plane view). It is a top view of the nozzle vane shown in FIG. It is a rear view of the nozzle vane shown in FIG. It is a front view which shows the impeller wheel for a turbocharger to which the 2nd Embodiment of the heat-resistant component of this invention was applied. It is a perspective view which shows the compressor blade which applied the 3rd Embodiment of the heat-resistant component of this invention. It is an electron microscope image of the cross section of the titanium sintered body of Comparative Example 2. It is an electron microscope image of the cross section of the titanium molten material of Reference Example 1.

Hereinafter, the titanium sintered body, ornaments, and heat-resistant parts of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

<Titanium sintered body>
First, an embodiment of the titanium sintered body of the present invention will be described.

The titanium sintered body according to the present embodiment is manufactured by, for example, a powder metallurgy method. Therefore, in such a titanium sintered body, particles of titanium-based powder (powder composed of a material containing titanium) are sintered.

The titanium sintered body according to the present embodiment is made of a material containing titanium, has an oxygen content of 2500 ppm or more and 5500 ppm or less in terms of mass ratio, and has a surface Vickers hardness of 250 or more and 500 or less. Such a titanium sintered body has excellent wear resistance. Therefore, for example, when applied to sliding parts, a titanium sintered body capable of maintaining good sliding characteristics for a long period of time even under severe sliding conditions can be obtained. Further, for example, when applied to an ornament, a titanium sintered body capable of suppressing scratches on the surface and maintaining an excellent aesthetic appearance can be obtained by giving the surface excellent wear resistance.

When the oxygen content is below the lower limit, the titanium oxide in the titanium sintered body is significantly reduced. Titanium oxide has the effect of increasing the corrosion resistance of the titanium sintered body and making it less likely to wear. Therefore, when the oxygen content is less than the lower limit value, titanium oxide is particularly reduced, and the corrosion resistance is lowered accordingly, so that the wear resistance is lowered. On the other hand, when the oxygen content exceeds the upper limit value, the titanium oxide in the titanium sintered body increases remarkably. Therefore, the ratio of metal bonds between metallic titanium is reduced, and the mechanical strength is lowered. As a result, for example, peeling or cracking is likely to occur on the sliding surface, and the frictional resistance is increased accordingly, so that the wear resistance is lowered.

Further, when the Vickers hardness of the surface is less than the lower limit value, when the titanium sintered body slides with the mating member, the surface of the titanium sintered body is gradually scraped by the mating member, and it becomes easy to wear. On the other hand, if the Vickers hardness of the surface exceeds the above upper limit value, the toughness of the titanium sintered body decreases, and when the load during sliding is extremely large or when an excessive impact is applied during sliding, titanium firing occurs. The bond may crack or break.

The oxygen content (elemental equivalent concentration) is preferably 3000 ppm or more and 5000 ppm or less, and more preferably 3500 ppm or more and 4500 ppm or less.

On the other hand, the Vickers hardness of the surface is preferably 300 or more and 450 or less, and more preferably 350 or more and 400 or less.

The oxygen content of the titanium sintered body can be measured by, for example, an atomic absorption spectrometer, an ICP emission spectroscopic analyzer, an oxygen-nitrogen simultaneous analyzer, or the like. In particular, the oxygen quantification method for metallic materials specified in JIS Z 2613 (2006) is also used. As an example, an oxygen / nitrogen analyzer manufactured by LECO, TC-300 / EF-300, is used.

On the other hand, the Vickers hardness of the surface can be measured by a method according to the test method of the Vickers hardness test specified in JIS Z 2244 (2009). The test force of the indenter is 9.8 N (1 kgf), and the holding time of the test force is 15 seconds. Then, the average value of the measurement results at 10 points is taken as the Vickers hardness of the surface.

It is preferable that at least a part of oxygen contained in the titanium sintered body exists in the state of titanium oxide as described above.

At this time, the titanium sintered body may contain any form of titanium oxide, but preferably contains particles containing titanium oxide as a main component (hereinafter, abbreviated as "titanium oxide particles"). It is considered that the titanium oxide particles share the stress applied to the metallic titanium as a matrix by being dispersed in the titanium sintered body. Therefore, by including the titanium oxide particles, the mechanical strength of the entire titanium sintered body can be improved. Further, since titanium oxide is harder than metallic titanium, the wear resistance of the titanium sintered body can be further improved by dispersing the titanium oxide particles.

For particles containing titanium oxide as a main component, for example, the components of the target particles are analyzed by a fluorescent X-ray analysis method or an electron probe microanalyzer, and the most abundant element is among titanium and oxygen. It refers to particles that have been analyzed to have one element and then the other element.

The average particle size of the titanium oxide particles is not particularly limited, but is preferably 0.5 μm or more and 20 μm or less, more preferably 1 μm or more and 15 μm or less, and further preferably 2 μm or more and 10 μm or less. When the average particle size of the titanium oxide particles is within the above range, the wear resistance can be enhanced without impairing the mechanical properties such as toughness and tensile strength of the titanium sintered body. That is, when the average particle size of the titanium oxide particles is less than the lower limit value, the stress sharing action of the titanium oxide particles may decrease depending on the content of the titanium oxide particles. Further, when the average particle size of the titanium oxide particles exceeds the upper limit value, the titanium oxide particles may become a starting point of cracks and the mechanical strength may decrease depending on the content of the titanium oxide particles.

Further, the crystal structure of the titanium oxide particles may be any of a rutile type, an anatase type and a brookite type, and a plurality of types may be mixed.

The average particle size of the titanium oxide particles is measured as follows. First, the cross section of the titanium sintered body is observed with an electron microscope, and 100 or more titanium oxide particles are randomly selected in the obtained observation image. At this time, whether or not the particles are titanium oxide particles can be specified by the contrast of the image, the surface analysis of oxygen, and the like. Next, the area of the titanium oxide particles selected on the observation image is calculated, and the diameter of a circle having the same area as this area is obtained. The circle thus obtained is regarded as the particle size (diameter equivalent to the circle) of the titanium oxide particles, and the average value for 100 or more titanium oxide particles is obtained. This average value is the average particle size of the titanium oxide particles.

Next, the crystal structure of the titanium sintered body will be described.
FIG. 1 is an electron microscope image showing an embodiment of the titanium sintered body of the present invention, and FIG. 2 is a diagram schematically showing a part of the electron microscope image shown in FIG. Note that FIG. 1 is an image of the cut surface of the titanium sintered body, and the dark band extending to the left and right at the upper end of FIG. 1 is an outer region of the titanium sintered body. That is, the lower end of the dark band corresponds to the surface of the titanium sintered body.

The titanium sintered body 1 shown in FIG. 2 contains an α phase 2 and a β phase 3 as a crystal structure. Of these, the α phase 2 refers to a region (titanium α phase) in which the crystal structure constituting the α phase 2 is mainly a hexagonal close-packed (hcp) structure. On the other hand, the β phase 3 refers to a region (titanium β phase) in which the crystal structure constituting the β phase 3 is mainly a body-centered cubic lattice (bcc) structure. In FIG. 1, the α phase 2 is shown as a region showing a relatively light color, and the β phase 3 is shown as a region showing a relatively dark color.

Since the α phase 2 has a relatively low hardness and is rich in ductility, it contributes to the realization of a titanium sintered body 1 having excellent strength and deformation resistance particularly at high temperatures. On the other hand, although the β phase 3 has a relatively high hardness, it is liable to undergo plastic deformation, which contributes to the realization of the titanium sintered body 1 having excellent toughness as a whole.

In the cross section of the titanium sintered body 1, it is preferable that most of it is occupied by such α phase 2 and β phase 3. The total occupancy rate (area ratio) of the α phase 2 and the β phase 3 is not particularly limited, but is preferably 95% or more, and more preferably 98% or more. In such a titanium sintered body 1, since α phase 2 and β phase 3 are dominant in terms of characteristics, many advantages of titanium are reflected.

The total occupancy of α-phase 2 and β-phase 3 is determined based on, for example, the difference in color development and contrast based on the difference in crystal structure by observing the cross section of the titanium sintered body 1 with an electron microscope or an optical microscope. It is obtained by distinguishing the crystal phase and measuring the area.

Examples of crystal structures other than α phase 2 and β phase 3 include ω phase and γ phase.
Further, the titanium sintered body 1 contains α phase 2 and β phase 3 as crystal structures as described above, and the occupancy rate (area ratio) of α phase 2 in the cross section is 70% or more and 99.8% or less. It is preferably 75% or more and 99% or less, and more preferably 80% or more and 98% or less. Since the α phase 2 is dominant in this way, the mechanical strength of the titanium sintered body 1 is increased, and the whole is likely to be homogeneous, so that the uniformity of wearability can also be enhanced. Therefore, when the titanium sintered body 1 is applied to a sliding component, the phenomenon of chained wear promotion due to the occurrence of a region that is easily worn locally on the sliding surface is suppressed, and the wear resistance is further improved. A titanium sintered body 1 is obtained. In other words, since the hardness difference between α-phase 2 and β-phase 3 is less likely to become apparent, the sliding surface becomes smoother and less likely to be caught during sliding, and thus wear resistance is reduced by reducing frictional resistance. Can contribute to the improvement of. Furthermore, the α phase 2, which is predominantly present, is less likely to be denatured by sliding because dislocations are less likely to occur, and has high corrosion resistance. Therefore, wear resistance can be maintained even when exposed to sliding for a long period of time. As a result, the polished polished surface can be well maintained for a long period of time.

On the other hand, when the α phase 2 has the above-mentioned occupancy rate, the β phase 3 has a smaller occupancy rate than that, but preferably exists at an area ratio of about 0.2% or more and 30% or less. It is more preferably present at an area ratio of about 1% or more and 25% or less, and even more preferably at an area ratio of about 2% or more and 20% or less. Since the β phase 3 is likely to undergo plastic deformation as described above, it promotes slippage between the α phases 2. Therefore, since the β phase 3 is present at a ratio within the above range, even if a large load is applied to the sliding surface during sliding, the influence of the load is mitigated by the sliding between the α phases 2. Can be made to. As a result, it becomes difficult to reduce the wear resistance even when a large load is applied.

Therefore, when the occupancy rate of α phase 2 is lower than the lower limit value, α phase 2 is no longer dominant in the crystal structure, although it depends on the ratio of α phase 2 and β phase 3, so that the sliding surface becomes smooth. There is a risk that it will become difficult to become and the frictional resistance during sliding will increase. Further, when the occupancy rate of α phase 2 exceeds the above upper limit value, the occupancy rate of β phase 3 becomes very small, although it depends on the content of crystal structures other than α phase 2 and β phase 3, so sliding. When a large load is applied to the surface, the effect may not be mitigated.

The occupancy rate of α phase 2 is measured as follows. First, the cross section of the titanium sintered body 1 is observed with an electron microscope, and the area of the obtained observation image is calculated. Next, the total area of α-phase 2 shown in the observation image is calculated. Then, the total area of the obtained α-phase 2 is divided by the area of the observation image to obtain the area ratio. This area ratio becomes the occupancy ratio of α phase 2.

Further, in the cross section of the titanium sintered body 1, it is one of the important factors that the α phase 2 is fine. For example, the average particle size of the α phase 2 in the cross section is preferably 3 μm or more and 30 μm or less, more preferably 5 μm or more and 25 μm or less, and further preferably 7 μm or more and 20 μm or less. Since the α phase 2 having such an average particle size is fine, dislocations are less likely to occur. Therefore, the hardness of the titanium sintered body 1 can be further increased, the sliding surface can be easily smoothed, and the frictional resistance can be further reduced. In addition, a well-polished polished surface can be maintained in that state for a long period of time.

Further, if the average particle size of the α phase 2 is less than the lower limit value, the particle size of the α phase 2 becomes too small, so that the occupancy rate of the α phase 2 may not be sufficiently increased. In addition, the mechanical strength of the titanium sintered body 1 may not be sufficiently increased. On the other hand, when the average particle size of the α phase 2 exceeds the upper limit value, dislocations are likely to occur in the α phase 2, so that the sliding surface is easily denatured and wear resistance when exposed to long-term sliding. There is a risk of reduced sex. In addition, the reduced wear resistance tends to scratch the polished surface, which may make it difficult to maintain the polished surface well for a long period of time. In addition, the mechanical strength mainly derived from α phase 2 may decrease.

The average particle size of α phase 2 is measured as follows. First, the cross section of the titanium sintered body 1 is observed with an electron microscope, and 100 or more α-phases 2 are randomly selected in the obtained observation image. Next, the area of the α phase 2 selected on the observation image is calculated, and the diameter of a circle having the same area as this area is obtained. The circle thus obtained is regarded as the particle size (diameter equivalent to the circle) of the α phase 2, and the average value for 100 or more α phases 2 is obtained. This average value is the average particle size of α phase 2.

The constituent material of the titanium sintered body 1 is a material containing titanium, and examples thereof include titanium alone or a titanium-based alloy.

The titanium-based alloy is an alloy containing titanium as a main component. In addition to titanium (Ti), for example, carbon (C), nitrogen (N), oxygen (O), aluminum (Al), and vanadium (V) , Niob (Nb), Zirconium (Zr), Titanium (Ta), Molybdenum (Mo), Chromium (Cr), Manganese (Mn), Cobalt (Co), Iron (Fe), Silicon (Si), Gallium (Ga) , Tin (Sn), barium (Ba), nickel (Ni), sulfur (S) and other elements.

Such a titanium-based alloy preferably contains an α-phase stabilizing element and a β-phase stabilizing element. The titanium sintered body 1 composed of such a titanium-based alloy can have both α-phase 2 and β-phase 3 as a crystal structure even if the production conditions and usage conditions thereof are changed, so that the titanium sintered body 1 has excellent weather resistance. It will be excellent. Therefore, the titanium sintered body 1 has both the characteristics exhibited by the α phase 2 and the characteristics exhibited by the β phase 3, and is particularly excellent in mechanical characteristics.

Among these, examples of the α-phase stabilizing element include aluminum, gallium, tin, carbon, nitrogen, oxygen and the like, and one or more of these are used in combination. On the other hand, examples of the β-phase stabilizing element include molybdenum, niobium, tantalum, vanadium, iron and the like, and one or more of these are used in combination.

Specific examples of the titanium-based alloy include titanium alloys specified in JIS H 4600: 2012 as 60 types, 60E types, 61 types, or 61F types. Specific examples thereof include Ti-6Al-4V, Ti-6Al-4V ELI, Ti-3Al-2.5V and the like. In addition, Ti-6Al-6V-2Sn, Ti-6Al-2Sn-4Zr-2Mo-0.08Si, Ti-6Al-2Sn-4Zr-6Mo, etc. specified in the Aerospace Material Standard (AMS) can be mentioned. .. In addition, Ti-5Al-2.5Fe, Ti-6Al-7Nb, etc. specified in the standards established by the International Organization for Standardization (ISO) can be mentioned. Further, Ti-13Zr-13Ta, Ti-6Al-2Nb-1Ta, Ti-15Zr-4Nb-4Ta, Ti-5Al-3Mo-4Zr and the like can be mentioned.

The above-mentioned notation of the alloy composition describes the components having a high concentration in order from the left, and the number in front of the element indicates the concentration of the element in mass%. For example, Ti-6Al-4V contains 6% by weight Al and 4% by weight V, indicating that the balance is Ti and impurities. The impurities are elements that are unavoidably mixed or intentionally added at a predetermined ratio (for example, 0.40% by mass or less in total of impurities).

The main range of the alloy composition described above is as follows.
The Ti-6Al-4V alloy contains Al in an amount of 5.5% by mass or more and 6.75% by mass or less, V in an amount of 3.5% by mass or more and 4.5% by mass or less, and the balance is Ti and impurities. As impurities, for example, Fe is 0.4% by mass or less, O is 0.2% by mass or less, N is 0.05% by mass or less, H is 0.015% by mass or less, and C is 0.08% by mass or less. It is permissible to include each in the ratio of. Furthermore, it is permissible that other elements are individually contained in an amount of 0.10% by mass or less, and a total of 0.40% by mass or less.

The Ti-6Al-4V ELI alloy contains Al in an amount of 5.5% by mass or more and 6.5% by mass or less, V in an amount of 3.5% by mass or more and 4.5% by mass or less, and the balance is Ti and impurities. .. As impurities, for example, Fe is 0.25% by mass or less, O is 0.13% by mass or less, N is 0.03% by mass or less, H is 0.0125% by mass or less, and C is 0.08% by mass or less. It is permissible to include each in the ratio of. Furthermore, it is permissible that other elements are individually contained in an amount of 0.10% by mass or less, and a total of 0.40% by mass or less.

The Ti-3Al-2.5V alloy contains Al in an amount of 2.5% by mass or more and 3.5% by mass or less, V in an amount of 1.6% by mass or more and 3.4% by mass or less, and optionally contains S. It contains 0.05% by mass or more and 0.20% by mass or less, and if necessary, at least one of La, Ce, Pr and Nd is contained in a total of 0.05% by mass or more and 0.70% by mass or less, and the balance is Ti and impurities. As impurities, for example, Fe is 0.30% by mass or less, O is 0.25% by mass or less, N is 0.05% by mass or less, H is 0.015% by mass or less, and C is 0.10% by mass or less. It is permissible to include each in the ratio of. Furthermore, it is permissible that other elements are contained in a total ratio of 0.40% by mass or less.

The Ti-5Al-2.5Fe alloy contains Al in an amount of 4.5% by mass or more and 5.5% by mass or less, Fe in an amount of 2% by mass or more and 3% by mass or less, and the balance is Ti and impurities. As impurities, for example, O may be contained in a proportion of 0.2% by mass or less, N in an amount of 0.05% by mass or less, H in an amount of 0.013% by mass or less, and C in an amount of 0.08% by mass or less. Permissible. Furthermore, it is permissible that other elements are contained in a total ratio of 0.40% by mass or less.

The Ti-6Al-7Nb alloy contains Al in an amount of 5.5% by mass or more and 6.5% by mass or less, Nb in an amount of 6.5% by mass or more and 7.5% by mass or less, and the balance is Ti and impurities. Examples of impurities include Ta of 0.50% by mass or less, Fe of 0.25% by mass or less, O of 0.20% by mass or less, N of 0.05% by mass or less, and H of 0.009% by mass or less. , C are allowed to be contained in a proportion of 0.08% by mass or less, respectively. Furthermore, it is permissible that other elements are contained in a total ratio of 0.40% by mass or less. Since the Ti-6Al-7Nb alloy has particularly low cytotoxicity as compared with other alloy types, it is particularly useful when the titanium sintered body 1 is used for biocompatible applications.

Further, the components contained in the titanium sintered body 1 are analyzed by a method based on the titanium-ICP emission spectroscopic analysis method specified in, for example, JIS H 1632-1 (2014) to JIS H 1632-3 (2014). be able to.

Further, the shape of the α phase 2 according to the present embodiment is preferably an isotropic shape or a shape similar thereto, not a needle shape. By having such a shape, as described above, it is possible to suppress a decrease in the fatigue strength of the titanium sintered body 1. As a result, a titanium sintered body 1 capable of maintaining a high mirror surface property for a long period of time can be obtained.

In addition, there is an aspect ratio as an index for evaluating the shape of the crystal structure. The average aspect ratio of α phase 2 is preferably 1 or more and 3 or less, and more preferably 1 or more and 2.5 or less. When the average aspect ratio of the α phase 2 is within the above range, a decrease in fatigue strength and hardness of the titanium sintered body 1 can be suppressed. Therefore, a titanium sintered body 1 useful as a structural component can be obtained. Further, by adjusting the average aspect ratio within the above range, when the titanium sintered body 1 is applied to the sliding parts, unevenness is less likely to occur on the sliding surface. As a result, the smoothness of the sliding surface can be further improved, and a titanium sintered body 1 having particularly low sliding resistance and excellent wear resistance can be obtained. When the aspect ratio exceeds the upper limit value, the shape anisotropy of the α phase 2 becomes large, so that the smoothness of the sliding surface may decrease and the sliding resistance may increase depending on the particle size of the α phase 2. ..

The average aspect ratio of α-phase 2 is measured as follows. First, the cross section of the titanium sintered body 1 is observed with an electron microscope, and 100 or more α-phases 2 are randomly selected in the obtained observation image. Next, the long axis of the α phase 2 selected on the observation image is specified, and the longest axis in the direction orthogonal to the long axis is specified as the short axis. Next, the major axis / minor axis is calculated as the aspect ratio. Then, the aspect ratios of 100 or more α-phases 2 are averaged, and this is taken as the average aspect ratio.

Further, in the titanium sintered body 1, it is preferable that the particle sizes of the α phase 2 are the same. In addition to the isotropic shape as described above or a shape similar to the shape of the α phase 2, the titanium sintered body 1 has high fatigue strength for a long period of time due to the fact that the particle size is uniform. It has excellent wear resistance.

Here, when the measurement result of the particle size of α phase 2 is plotted in the plot area where the particle size of α phase 2 is taken on the horizontal axis and the number of α phase 2 corresponding to the particle size is taken on the vertical axis, the α phase is plotted. A particle size distribution of 2 is obtained. In this particle size distribution, the particle size when the cumulative number from the small diameter side is 16% of the total is D16, and the particle size when the cumulative number from the small diameter side is 84% of the total is D84. At this time, the standard deviation SD of the particle size distribution is calculated by the following formula.
SD = (D84-D16) / 2

The standard deviation SD obtained in this way serves as a guide for the distribution width of the particle size distribution. In the titanium sintered body 1, the standard deviation SD of the particle size distribution of the α phase 2 is preferably 5 or less, more preferably 3 or less, and further preferably 2 or less. The titanium sintered body 1 in which the standard deviation SD of the particle size distribution of the α phase 2 is within the above range has a sufficiently narrow particle size distribution and a sufficiently uniform particle size of the α phase 2. Such a titanium sintered body 1 has particularly high fatigue strength and can maintain excellent wear resistance for a long period of time.

Further, the titanium sintered body 1 is subjected to crystal structure analysis by an X-ray diffraction method, and the acquired X-ray diffraction spectrum includes, for example, a peak of reflection intensity due to the α phase and a peak of the reflection intensity due to the β phase. including.

The X-ray diffraction spectrum obtained by the X-ray diffraction method particularly includes a peak of the reflection intensity due to the plane orientation (100) of the titanium α phase and a peak of the reflection intensity due to the plane orientation (110) of the titanium β phase. Is preferable. Then, in the X-ray diffraction spectrum, the peak value (peak top value) of the reflection intensity due to the plane orientation (110) of the titanium β phase is the peak value (peak) of the reflection intensity due to the plane orientation (100) of the titanium α phase. The top value) is preferably 5% or more and 60% or less, more preferably 10% or more and 50% or less, and further preferably 15% or more and 40% or less. As a result, the above-mentioned characteristics of the α phase 2 and the characteristics of the β phase 3 are manifested without being buried. That is, since α phase 2 is less likely to cause dislocations, it is less likely to be denatured by sliding and has high corrosion resistance. On the other hand, since the β phase 3 promotes the sliding between the α phases 2, even when a large load is applied to the sliding surface, the influence of the load can be mitigated by the sliding between the α phases 2. Therefore, by manifesting each of these functions, a synergistic effect can be obtained without canceling each other's effects. As a result, a titanium sintered body 1 that can maintain excellent wear resistance for a long period of time even when a large load is applied to the sliding surface can be obtained.

The peak of the reflection intensity due to the plane orientation (100) of the titanium α phase is located near 35.3 ° in 2θ. On the other hand, the peak of the reflection intensity due to the plane orientation (110) of the titanium β phase is 2θ located in the vicinity of 39.5 °.

Further, Cu—Kα ray is used as the X-ray source of the X-ray diffractometer, the tube voltage is 30 kV, and the tube current is 20 mA.

Further, the titanium sintered body 1 preferably has a relative density of 99% or more, more preferably 99.5% or more. When the relative density of the titanium sintered body 1 is within the above range, it becomes difficult for holes to be exposed on the sliding surface. For this reason, wear starting from the pores is less likely to occur, and the frictional resistance is reduced, so that the titanium sintered body 1 exhibiting particularly good wear resistance can be obtained.

The relative density of the titanium sintered body 1 is a dry density measured according to the density test method of the sintered metal material specified in JIS Z 2501: 2000.

The titanium sintered body 1 as described above can be applied to various uses, and the use is not particularly limited, but it is particularly useful as an ornament or a sliding part described later.

<Manufacturing method of titanium sintered body>
Next, a method for producing the titanium sintered body 1 will be described.

The method for producing the titanium sintered body 1 includes [1] a step of mixing a titanium-based powder and an organic binder to obtain a mixture, and [2] a step of molding the mixture by a powder molding method to obtain a molded body. 3] A step of degreasing the molded body to obtain a degreased body, [4] a step of firing the degreased body to obtain a sintered body, and [5] a hot isotropic pressure treatment (HIP treatment) on the sintered body. It has a step of applying the above. Hereinafter, each step will be described in sequence.

[1] Mixing Step First, a titanium-based powder, which is a raw material of the titanium sintered body 1, is kneaded together with an organic binder to obtain a kneaded product (mixture).

The average particle size of the titanium-based powder is not particularly limited, but is preferably 1 μm or more and 50 μm or less, and more preferably 5 μm or more and 40 μm or less.

The titanium-based powder is a titanium simple substance powder or a titanium alloy powder. The titanium alloy powder may be a powder composed of only particles having a single alloy composition (pre-alloy powder), or may be a mixed powder (premix powder) formed by mixing a plurality of types of particles having different compositions from each other. good. In the case of the premix powder, the individual particles may be particles containing only one kind of element or particles containing a plurality of elements, as long as the entire premix powder satisfies the composition ratio as described above. good.

The content of the organic binder in the kneaded product is appropriately set according to the molding conditions, the shape to be molded, etc., but is preferably about 2% by mass or more and 20% by mass or less of the entire kneaded product, and is 5% by mass or more. It is more preferably about 10% by mass or less. By setting the content of the organic binder within the above range, the kneaded product has good fluidity. As a result, the filling property of the kneaded product during molding is improved, and a sintered body having a shape (near net shape) closer to the desired shape can be finally obtained.

Examples of the organic binder include polyolefins such as polyethylene, polypropylene and ethylene-vinyl acetate copolymer, acrylic resins such as polymethylmethacrylate and polybutylmethacrylate, styrene resins such as polystyrene, polyvinyl chloride and polyvinylidene chloride. Polyesters such as polyamide, polyethylene terephthalate, polybutylene terephthalate, various resins such as polyether, polyvinyl alcohol, polyvinylpyrrolidone or copolymers thereof, various waxes, paraffins, higher fatty acids (eg, stearic acid), higher alcohols, higher grades. Examples thereof include various organic binders such as fatty acid esters and higher fatty acid amides, and one or a mixture of two or more of these can be used.

Further, a plasticizer may be added to the kneaded product, if necessary. Examples of this plasticizer include phthalates (eg, DOP, DEP, DBP), adipates, trimellitic acids, sebacic acids and the like, and one or more of these are mixed. Can be used.

Further, in addition to the titanium powder, the organic binder, and the plasticizer, various additives such as a lubricant, an antioxidant, a degreasing accelerator, and a surfactant may be added to the kneaded product as needed. can.

The kneading conditions vary depending on various conditions such as the alloy composition and particle size of the titanium powder used, the composition of the organic binder, and the blending amount thereof. For example, the kneading temperature is about 50 ° C. or higher and 200 ° C. or lower. The kneading time can be about 15 minutes or more and 210 minutes or less.

In addition, the kneaded product is made into pellets (small lumps) as needed. The particle size of the pellet is, for example, about 1 mm or more and 15 mm or less.

In addition, depending on the molding method described later, a granulated powder (mixture) may be produced instead of the kneaded product.

[2] Molding Step Next, the obtained kneaded product (mixture) is molded to produce a molded product.

The molding method is not particularly limited, and for example, various powder molding methods such as a compact molding (compression molding) method, a metal injection molding (MIM) method, and an extrusion molding method can be used. Of these, the metal powder injection molding method is preferably used from the viewpoint of being able to produce a near-net-shaped sintered body.

Further, the molding conditions in the case of the compaction molding method vary depending on various conditions such as the composition and particle size of the titanium-based powder used, the composition of the organic binder, and the blending amount thereof, but the molding pressure is 200 MPa or more and 1000 MPa or less (2t). / cm ² or more 10t / cm ² or less) about a is preferably.

In the case of titanium powder, the molding conditions are different depending on various conditions, but the material temperature is 80 ° C. or higher and 210 ° C. or lower, and the injection pressure is 50 MPa or higher and 500 MPa or lower (0.5 t / cm ² or higher and 5 t / cm ² or lower). ) Is preferable.

Further, the molding conditions in the case of the extrusion molding method are different depending on various conditions, but the material temperature is about 80 ° C. or more and 210 ° C. or less, and the extrusion pressure is 50 MPa or more and 500 MPa or less (0.5 t / cm ² or more and 5 t / cm ² or less). ) Is preferable.

The molded product thus obtained is in a state in which the organic binder is uniformly distributed in the gaps between the particles of the titanium-based powder.

The shape and dimensions of the molded product to be produced are determined in consideration of the shrinkage of the molded product in the subsequent degreasing step and firing step.

Further, if necessary, the molded body may be machined such as cutting, polishing, and cutting. Since the molded product has a relatively low hardness and is relatively rich in plasticity, it can be easily machined while preventing the shape of the molded product from collapsing. According to such machining, the titanium sintered body 1 having high dimensional accuracy can be finally obtained more easily.

[3] Solventing Step Next, the obtained molded product is subjected to a degreasing treatment (degreasing treatment) to obtain a degreased body.

Specifically, by heating the molded product to decompose the organic binder, at least a part of the organic binder is removed from the molded product, and a degreasing treatment is performed.

Examples of this degreasing treatment include a method of heating the molded product, a method of exposing the molded product to a gas that decomposes the binder, and the like.

When the method of heating the molded body is used, the heating conditions of the molded body are about 100 ° C. or higher and 750 ° C. or lower × 0.1 hour or more and 20 hours or less, although the heating conditions of the molded body differ slightly depending on the composition and the blending amount of the organic binder. It is more preferable that the temperature is 150 ° C. or higher and 600 ° C. or lower × 0.5 hours or longer and 15 hours or lower. As a result, the molded product can be degreased in a necessary and sufficient manner without sintering the molded product. As a result, it is possible to reliably prevent a large amount of the organic binder component from remaining inside the degreased body.

The atmosphere for heating the molded body is not particularly limited, and is a reducing gas atmosphere such as hydrogen, an inert gas atmosphere such as nitrogen or argon, an oxidizing gas atmosphere such as air, or these atmospheres. A reduced pressure atmosphere in which the pressure is reduced is mentioned.

On the other hand, examples of the gas that decomposes the binder include ozone gas and the like.
By dividing the degreasing step into a plurality of processes (steps) having different degreasing conditions, the organic binder in the molded product is decomposed and removed more quickly and so as not to remain in the molded product. be able to.

Further, if necessary, the degreased body may be machined such as cutting, polishing, and cutting. Since the degreased body has a relatively low hardness and is relatively rich in plasticity, it can be easily machined while preventing the shape of the degreased body from being deformed. According to such machining, the titanium sintered body 1 having high dimensional accuracy can be finally obtained more easily.

[4] Baking Step Next, the obtained degreased body is fired in a baking furnace to obtain a sintered body. That is, diffusion occurs at the interface between the particles of the titanium-based powder, leading to sintering. As a result, the titanium sintered body 1 is obtained.

The firing temperature varies depending on the composition, particle size, etc. of the titanium-based powder, but is, for example, about 900 ° C. or higher and 1400 ° C. or lower. Further, it is preferably about 1050 ° C. or higher and 1300 ° C. or lower.

The firing time is 0.2 hours or more and 7 hours or less, but preferably 1 hour or more and 6 hours or less.

In the firing step, the sintering temperature and the firing atmosphere described later may be changed during the firing step.

The atmosphere during firing is not particularly limited, but in consideration of preventing significant oxidation of the metal powder, a reducing gas atmosphere such as hydrogen, an inert gas atmosphere such as argon, or these atmospheres. A reduced pressure atmosphere or the like in which the pressure is reduced is preferably used.

When the titanium sintered body 1 is produced from the titanium-based powder, both the α phase 2 and the β phase 3 may be formed depending on the firing conditions and the like. In particular, when the above-mentioned β-phase stabilizing element is contained in the titanium-based powder, β-phase 3 is formed more reliably.

On the other hand, the oxygen content of the titanium sintered body 1 can be adjusted by optimizing various manufacturing conditions. For example, the titanium sintered body 1 is manufactured using a titanium-based powder, and the oxygen content of the titanium sintered body 1 can be adjusted by appropriately changing the oxygen content of the titanium-based powder. Specifically, when producing titanium-based powder from molten metal (melt of raw material), the powder in the uncooled state (high temperature state) is exposed to water or an oxygen-containing atmosphere, or the contact time is secured for a long time. By doing so, the oxygen content of the titanium-based powder can be increased. Since the oxygen contained in the titanium-based powder exists in a state such as titanium oxide and easily migrates to the titanium sintered body 1 as it is, the oxygen content of the titanium sintered body 1 can be increased.

Although the oxygen content of the titanium-based powder used is not particularly limited, it is preferably 300 ppm or more and 5000 ppm or less, and more preferably 500 ppm or more and 3000 ppm or less in terms of mass ratio. By using such an alloy powder having an oxygen content, it is possible to obtain a titanium sintered body 1 having a relatively high oxygen content without impairing the sinterability of the titanium-based powder.

In addition to this, oxygen is supplied from the decomposition product of the organic binder, and oxygen is supplied from the furnace body and atmosphere of the heating furnace, which is also one of the factors for increasing the oxygen content.

Further, by optimizing various manufacturing conditions, the ratio occupied by the α phase 2 in the titanium sintered body 1, that is, the area ratio occupied by the α phase 2 in the cross section of the titanium sintered body 1 can also be adjusted. For example, as the firing temperature increases, the proportion of β-phase 3 increases, so the firing temperature is adjusted so that the proportion of β-phase 3 falls within the target range, and the crystal structure becomes enlarged due to the firing time being too long. The firing time may be set in consideration of.

Therefore, for example, when the titanium sintered body 1 is manufactured using a titanium-based powder containing almost no β-phase 3, the proportion of β-phase 3 increases as the firing temperature increases, depending on the composition of the titanium-based powder. Since there is a tendency, the firing temperature may be adjusted so that the area ratio of the α phase 2 falls within the above range, and the firing time may be set so as not to cause insufficient sintering or oversintering by adjusting the firing temperature.

Further, with the optimization of such production conditions, the particle size of α-phase 2 can also be adjusted. Since the particle size of α-phase 2 tends to increase as the firing temperature is raised or the firing time is lengthened, the firing temperature and firing time should be set so that the particle size of α-phase 2 falls within the above range. Just do it.

Further, the hardness of the surface of the titanium sintered body 1 tends to depend on the particle size of the α phase 2. If the particle size of the α phase 2 is reduced, the hardness tends to increase, and if the particle size of the α phase 2 is increased, the hardness tends to decrease. Therefore, the Vickers hardness of the surface of the titanium sintered body 1 can be kept within the above range by setting the firing temperature and the firing time in order to adjust the particle size of the α phase 2.

When the average particle size of the α phase 2 is within the above range, the shape of the α phase 2 tends to approach an isotropic shape as the area ratio of the α phase 2 increases. It is considered that this is because the probability that the α phases 2 are adjacent to each other increases as the ratio of the β phase 3 decreases, and the anisotropic grain growth is hindered by the α phases 2 interfering with each other. Be done. Therefore, it is possible to adjust the aspect ratio as well as the particle size of the α phase 2.

[5] HIP Step Further, the sintered body thus obtained may be further subjected to a HIP treatment (hot isotropic pressure treatment) or the like. As a result, the density of the sintered body can be further increased, and an ornament having more excellent mechanical properties can be obtained.

The conditions for the HIP treatment are, for example, a temperature of 850 ° C. or higher and 1200 ° C. or lower, and a time of 1 hour or more and 10 hours or less.

The pressing force is preferably 50 MPa or more, and more preferably 100 MPa or more and 500 MPa or less.

Further, if necessary, the obtained sintered body may be further subjected to annealing treatment, solution treatment, aging treatment, hot working treatment, cold working treatment and the like.

If necessary, the obtained titanium sintered body 1 may be machined, for example, by polishing. The polishing treatment is not particularly limited, and examples thereof include electrolytic polishing, buffing, dry polishing, chemical polishing, barrel polishing, and sandblasting. By performing these polishing treatments, the surface of the titanium sintered body 1 can be given a further metallic luster and the mirror surface property can be improved. A surface having a high mirror surface has a small sliding resistance, so that the surface has more excellent wear resistance.

<Ornaments>
Next, an embodiment of the ornament of the present invention will be described.

The ornaments according to the present embodiment include, for example, a watch case (body, back cover, one-piece case in which the body and back cover are integrated, etc.), a watch band (band clasp, band / bangle attachment / detachment mechanism, etc.). ), Bezel (eg, rotating bezel, etc.), crown (eg, screw-locking crown, etc.), buttons, glass edges, dial rings, parting plates, watch exterior parts such as packing, glasses (eg, glasses frame) ), Tie pins, cufflinks, rings, necklaces, bracelets, ankles, broaches, pendants, earrings, jewelry such as piercings, spoons, forks, chopsticks, knives, butter knives, tableware such as stoppers, lighters or their cases For equipment such as sports equipment such as golf clubs, nameplates, panels, prize cups, and other housings (eg housings for mobile phones, smartphones, tablet terminals, wearable terminals, mobile computers, music players, cameras, shavers, etc.) Examples include exterior parts. All of these ornaments may be valued for their excellent aesthetic appearance. When these ornaments contain at least a part of the titanium sintered body 1, the surface of the ornament can be provided with excellent wear resistance. As a result, scratches and abrasion are suppressed, and an ornament that can maintain an excellent aesthetic appearance for a long period of time can be obtained. At the same time, the surface of the ornament can be given a mirror surface property. From this point of view, the ornament according to the present embodiment is excellent in aesthetic appearance.

FIG. 3 is a perspective view showing a watch case to which the embodiment of the ornament of the present invention is applied, and FIG. 4 is a partial cross-sectional perspective view showing a bezel to which the embodiment of the ornament of the present invention is applied. ..

The watch case 11 shown in FIG. 3 includes a case main body 112 and a band attachment portion 114 which is provided so as to project from the case main body 112 and for attaching a watch band. In such a watch case 11, a container can be constructed together with a glass plate and a back cover (not shown). A movement, a dial, etc. (not shown) are stored in this container. Therefore, this container protects the movement and the like from the external environment and has a great influence on the aesthetic appearance of the watch.

The bezel 12 shown in FIG. 4 has an annular shape, is attached to the watch case, and can rotate with respect to the watch case as needed. When the bezel 12 is attached to the watch case, the bezel 12 is located on the outside of the watch case, so that the bezel 12 influences the aesthetic appearance of the watch.

Further, since such a watch case 11 and a bezel 12 are used in a state of being attached to a human body, they are always easily scratched. Therefore, by using the titanium sintered body 1 as a constituent material of such an ornament, an ornament having a high mirror surface and an excellent aesthetic appearance can be obtained. Furthermore, this mirror property can be maintained for a long period of time.

In addition, the watch case 11 and the bezel 12 may be subjected to a polishing process in order to remove scratches on the surface (overhaul). Even if the watch case 11 and the bezel 12 including the titanium sintered body 1 according to the present embodiment are subjected to such a polishing treatment, they are unlikely to be significantly worn or uneven, so that the polishing treatment is performed. It is easy to apply. That is, even if such a watch case 11 or a bezel 12 is subjected to a polishing treatment, it is possible to maintain a state in which the surface has a high mirror surface and is excellent in aesthetic appearance (the mirror surface may be deteriorated by polishing). Less is).

<Sliding parts>
Next, sliding parts will be described as an application example of the titanium sintered body 1 of the present invention.

Sliding parts include, for example, parts for industrial machines such as parts for electric motors, parts for generators, parts for pumps, parts for compressors, and parts for automobiles (for example, engine components such as pistons, tappets, and conrods). Etc.), bicycle parts, railroad vehicle parts, marine parts, aircraft parts, transportation equipment parts such as space transporter parts (for example, rockets, etc.), personal computer parts, mobile phone terminal parts, consumer robots Parts for electronic devices such as parts for electronic devices, parts for refrigerators, parts for washing machines, parts for electrical devices such as parts for air conditioners, parts for machine tools, parts for semiconductor manufacturing equipment, parts for industrial robots Examples include parts for plants, nuclear power plants, thermal power plants, hydroelectric power plants, refineries, plant parts used in plants such as chemical complexes.

All of these slide with the mating member in a state where a load is applied to the sliding surface. Therefore, by using the titanium sintered body 1 for at least a part of such sliding parts, a sliding parts having excellent wear resistance for a long period of time can be realized.

<Heat-resistant parts>
<< First Embodiment >>
The heat-resistant parts of the present invention can be applied to, for example, parts for a supercharger. The turbocharger component described later is the first embodiment of the heat-resistant component of the present invention, and includes the titanium sintered body described above. That is, at least a part of the turbocharger parts described later is made of the titanium sintered body described above. Such turbocharger parts become heat-resistant parts with high density and excellent wear resistance and heat resistance without any additional treatment (or by less additional treatment).

Examples of such turbocharger parts include a nozzle vane for a turbocharger, a turbine wheel for a turbocharger, an impeller wheel for a turbocharger, a wastegate valve, a turbine shaft, a housing, a drive ring, a drive lever, a nozzle ring, a nozzle plate, and a unison. Rings, arms, links, rods and the like can be mentioned. All of these turbocharger parts may be exposed to high temperatures for a long period of time, and in some cases, they slide with other parts, so that wear resistance is required. As described above, the titanium sintered body of the present invention has excellent heat resistance and mechanical properties due to its high density. Therefore, a turbocharger component having excellent long-term durability can be obtained.

Hereinafter, as an example of the turbocharger parts, a turbocharger nozzle vane (hereinafter, also abbreviated as “nozzle vane”) will be described. The nozzle vane is used in a variable displacement turbocharger and is a valve body for controlling the boost pressure by adjusting the nozzle opening degree.

FIG. 6 is a side view (viewing a wing portion in a plan view) showing a turbocharger nozzle vane to which the first embodiment of the heat-resistant component of the present invention is applied, and FIG. 7 is a plan view of the nozzle vane shown in FIG. FIG. 8 is a rear view of the nozzle vane shown in FIG.

The nozzle vane 4 shown in FIG. 6 has a shaft portion 41 and a wing portion 42.
The cross-sectional shape of the main portion of the shaft portion 41 is circular with the axis 43 as the central axis. The shaft portion 41 has a portion on the wing portion 42 side (left side in FIG. 6) rotatably supported by a nozzle mount (not shown), and a portion on the side opposite to the wing portion 42 (right side in FIG. 6). It is fixed to a nozzle plate (not shown). As a result, the blade portion 42 can be rotated around the axis 43 to change the angle thereof, and the nozzle opening degree can be adjusted.

Further, a center hole 44 is formed on one end surface of the shaft portion 41 (the end surface on the right side in FIG. 6). The center hole 44 has a circular cross-sectional shape, and its center is formed so as to coincide with the axis 43.

Further, a pair of flat portions 45 (two-sided cut portions) facing each other via the axis 43 are provided on the outer peripheral surface of one end side (right side in FIG. 6) of the shaft portion 41 (see FIG. 8). ..

Each of such flat portions 45 is used in a state of being abutted against a abutting surface formed on a lever plate (not shown). The rotation angle of the shaft portion 41 around the axis 43 is regulated, and the rotation angle of the nozzle vane 4 around the axis 43 can be adjusted with high accuracy. Further, each flat portion 45 is formed so as to be inclined at an angle θ with respect to the projecting direction (blade surface) of the blade portion 42 (see FIG. 8).

On the other hand, a wing portion 42 is provided on the other end side of the shaft portion 41 (the end portion on the left side in FIG. 6). That is, the wing portion 42 is provided so as to project from one end of the shaft portion 41.

Further, on the other end side of the shaft portion 41, a flange portion 46 projecting to the outside of the shaft portion 41 is formed.

As shown in FIG. 6, such a wing portion 42 has a strip shape extending in a direction perpendicular to the axis 43 of the shaft portion 41 in a plan view thereof. Further, the protruding length of the wing portion 42 from the shaft portion 41 is longer on one end side (lower side in FIG. 6) than on the other end side (upper side in FIG. 6).

Further, chamfers 47 and 48 are provided on the edges of the wing portion 42 at both ends in the width direction (horizontal direction in FIG. 6) in a plan view.

Further, as shown in FIGS. 7 and 8, the wing portion 42 is slightly curved in the thickness direction thereof. Further, the thickness of the wing portion 42 gradually decreases toward each end in the extending direction (protruding direction).

The nozzle vane 4 as described above contains the titanium sintered body of the present invention. As a result, the nozzle vane 4 has excellent heat resistance and mechanical properties, and has excellent wear resistance. Further, the nozzle vane 4 has high dimensional accuracy even if it has a complicated shape. As a result, it is possible to realize a turbocharger capable of exhibiting excellent performance for a long period of time.
The shape and the like of the nozzle vane 4 described above are examples, and are not limited.

<< Second Embodiment >>
FIG. 9 is a front view showing an impeller wheel for a turbocharger to which the second embodiment of the heat-resistant component of the present invention is applied. An impeller wheel for a turbocharger (hereinafter, abbreviated as "impeller wheel") is a component that generates a rotational force by receiving pressure such as exhaust gas in a turbocharger.

The impeller wheel 5 shown in FIG. 9 has a hub portion 54 and a plurality of wing portions 55 provided on the outer peripheral surface of the hub portion 54.
Further, the hub portion 54 is provided with a through hole 541 through which the shaft is penetrated.

The plurality of wing portions 55 include a long wing portion 551 and a short wing portion 552 having different lengths in the direction of the rotation axis 530 of the impeller wheel 5. The long wing portions 551 and the short wing portions 552 are alternately arranged at equal intervals in the circumferential direction of the outer periphery of the hub portion 54.

Further, the long wing portion 551 is arranged from the lower end to the upper end of the impeller wheel 5 shown in FIG. The long wing portion 551 has a shape curved in the circumferential direction of the outer circumference of the hub portion 54.

On the other hand, although the short wing portion 552 is arranged from the lower end to the upper end of the impeller wheel 5 shown in FIG. 9, it is arranged so as to be shorter than the long wing portion 551. The short wing portion 552 also has a shape curved in the circumferential direction of the outer circumference of the hub portion 54.

Such an impeller wheel 5 contains the titanium sintered body of the present invention. As a result, the impeller wheel 5 has excellent heat resistance and mechanical properties, and has excellent wear resistance. Further, the impeller wheel 5 has high dimensional accuracy even if it has a complicated three-dimensional shape. As a result, it is possible to realize a turbocharger capable of exhibiting excellent performance for a long period of time.

The shape and the like of the impeller wheel 5 described above are examples, and are not limited.

<< Third Embodiment >>
The heat-resistant component of the present invention can be applied to, for example, a compressor blade which is a component for a jet engine or a component for a power generation turbine. Such a compressor blade is a third embodiment of the heat-resistant component of the present invention, and at least a part thereof is made of the titanium sintered body of the present invention.

FIG. 10 is a perspective view showing a compressor blade to which the third embodiment of the heat-resistant component of the present invention is applied. The compressor blade 6 shown in FIG. 10 includes an inner rim 61 and an outer rim 62 provided concentrically with each other, and a blade portion 63 provided between them and arranged in the circumferential direction of the inner rim 61. I have. The inner rim 61 and the outer rim 62 each have a shape obtained by cutting out a part of an annulus. That is, the compressor blade 6 shown in FIG. 10 corresponds to one segment among those in which the entire annular compressor blade is divided into a plurality of segments. Further, the wing portion 63 has a flat plate shape including a curved curved surface. The blade tip (end surface) of the blade portion 63 is coupled to the outer peripheral surface of the inner rim 61 and the inner peripheral surface of the outer rim 62.

Such a compressor blade 6 is one of the components constituting a jet engine or a gas turbine for power generation, and a turbine shaft (not shown) provided inside the inner rim 61 when the blade portion 63 receives gas receives gas. To rotate. As a result, the compressor can compress the gas in the jet engine or the gas turbine for power generation.

The inner rim 61, the outer rim 62, and the wing portion 63 may be separate members from each other, but in the compressor blade 6 shown in FIG. 10, the inner rim 61, the outer rim 62, and the wing portion 63 are integrated. ing. Therefore, the relative position accuracy of each part is high, and the performance as a compressor blade is excellent. Then, by forming the entire compressor blade 6 with the titanium sintered body of the present invention, the compressor blade 6 having excellent dimensional accuracy can be obtained.

Further, in general, in a compressor blade, from the necessity of improving aerodynamic performance, the shape of the blade portion is required to be a three-dimensional shape including a thinner and curved curved surface.

In response to this problem, since the entire compressor blade 6 is made of a sintered body manufactured by a powder metallurgy method, even if the blade portion 63 having a thin and complicated three-dimensional shape is included, the dimensions are large. The compressor blade 6 with high accuracy can be realized.

Further, since the titanium sintered body of the present invention has high density and excellent heat resistance, it also contributes to the improvement of the mechanical properties of the compressor blade 6. That is, since the compressor blade is generally a component that constitutes an air flow path, sufficient fatigue strength and wear resistance against vibration are required even at high temperatures.

In response to this problem, since the compressor blade 6 is made of the titanium sintered body of the present invention, it has a high density, excellent heat resistance, and sufficient wear resistance. Therefore, the compressor blade 6 having excellent long-term durability can be obtained.

Further, since it is manufactured by using various molding methods, post-processing after sintering is hardly required or the amount of processing can be suppressed to be small in the production of the compressor blade 6. Further, as described above, since the density is increased, additional processing such as HIP processing is not required. Therefore, the manufacturing cost can be reduced, and the occurrence of defects caused by post-processing marks can be minimized.

The shape of the compressor blade and the like described above are examples, and are not limited. For example, the compressor blade 6 shown in FIG. 10 is a so-called stationary blade, but the compressor blade may be a moving blade.

Further, the titanium sintered body of the present invention includes parts other than the compressor such as other parts constituting a jet engine and a gas turbine for power generation, such as fan blades, turbine blades, fan disks, mounts, shafts, combustors, and exhaust ports. It can also be applied to the components that make up.

The titanium sintered body, ornaments, and heat-resistant parts of the present invention have been described above based on suitable embodiments, but the present invention is not limited thereto.

For example, the use of the titanium sintered body is not limited to ornaments, sliding parts, heat-resistant parts, and the like, and may be any other structure (structural part). Examples of this structural part include parts for automobiles, parts for bicycles, parts for railway vehicles, parts for ships, parts for aircraft, parts for transportation equipment such as parts for space transport machines (for example, rockets), and parts for personal computers. , Electronic equipment parts such as mobile phone terminal parts, electrical equipment parts such as refrigerators, washing machines, air conditioners, machine tools, mechanical parts such as semiconductor manufacturing equipment, nuclear power plants, thermal power plants, Examples include plant parts such as hydropower plants, refineries and chemical complexes, surgical instruments, artificial bones, artificial joints, artificial teeth, artificial tooth roots, and medical equipment such as orthodontic parts.

Since the titanium sintered body has high biocompatibility, it is particularly useful as an artificial bone or a dental metal part. Of these, the dental metal part is not particularly limited as long as it is a metal part that is temporarily or semi-permanently placed in the oral cavity, and is, for example, an inlay, a crown, a bridge, a metal bed, a denture, an implant, an abutment, or a fixture. Examples include metal frames such as chars and screws.

Next, specific examples of the present invention will be described.
1. 1. Production of Titanium Sintered Body (Example 1)
<1> First, a Ti-6Al-4V alloy powder having an average particle size of 23 μm produced by the gas atomization method was prepared.

Next, a mixture of polypropylene and wax (organic binder) was prepared and weighed so that the mass ratio of the raw material powder and the organic binder was 9: 1 to obtain a composition for producing a titanium sintered body.

Next, the obtained composition for producing a titanium sintered body was kneaded with a kneader to obtain a compound. Then, the compound was processed into pellets.

<2> Next, using the obtained pellets, molding was performed under the molding conditions shown below to prepare a molded product.

<Molding conditions>
-Molding method: Metal powder injection molding-Material temperature: 150 ° C
-Injection pressure: 11 MPa (110 kgf / cm ² )

<3> Next, the obtained molded product was subjected to a degreasing treatment under the following degreasing conditions to obtain a degreased body.

<Solvent degreasing conditions>
・ Solvent temperature: 520 ° C
・ Solventing time: 5 hours ・ Solventing atmosphere: Nitrogen gas atmosphere

<4> Next, the obtained degreased body was calcined under the calcining conditions shown below. A sintered body was produced in this way.

<Baking conditions>
・ Baking temperature: 1100 ℃
・ Baking time: 5 hours ・ Baking atmosphere: Argon gas atmosphere ・ Atmospheric pressure: Atmospheric pressure (100 kPa)

<5> Next, the obtained sintered body was subjected to HIP treatment under the following treatment conditions. In this way, a rod-shaped titanium sintered body having a diameter of 5 mm and a length of 100 mm was obtained.

<HIP processing conditions>
・ Processing temperature: 900 ℃
-Treatment time: 3 hours-Treatment pressure: 1480 kgf / cm ² (145 MPa)

<6> Next, the obtained titanium sintered body was cut, and the cut surface was buffed.
Next, the polished surface was observed with an electron microscope, and the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were determined, respectively. The results are shown in Table 1.

(Examples 2 to 6)
The same as in Example 1 except that the production conditions were changed so that the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were the values shown in Table 1, respectively. To obtain a titanium sintered body.

(Comparative Examples 1 to 4)
The same as in Example 1 except that the production conditions were changed so that the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were the values shown in Table 1, respectively. To obtain a titanium sintered body.

(Reference example 1)
First, a molten material of Ti-6Al-4V alloy was prepared.

Next, the obtained molten material was cut and the polished surface was buffed.
Next, the polished surface was observed with an electron microscope, and the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were determined, respectively. The results are shown in Table 1.

(Example 7)
A titanium sintered body was obtained in the same manner as in Example 1 except that a Ti-3Al-2.5V alloy powder having an average particle size of 23 μm was used instead of the Ti-6Al-4V alloy powder.
Then, the obtained titanium sintered body was cut, and the cut surface was buffed.

Next, the polished surface was observed with an electron microscope, and the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were determined, respectively. The results are shown in Table 2.

(Examples 8 to 12)
The same as in Example 7 except that the production conditions were changed so that the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were the values shown in Table 2, respectively. To obtain a titanium sintered body.

(Comparative Examples 5 to 8)
The same as in Example 7 except that the production conditions were changed so that the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were the values shown in Table 2, respectively. To obtain a titanium sintered body.

(Reference example 2)
First, a molten material of Ti-3Al-2.5V was prepared.

Next, the obtained molten material was cut and the polished surface was buffed.
Next, the polished surface was observed with an electron microscope, and the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were determined, respectively. The results are shown in Table 2.

(Example 13)
A titanium sintered body was obtained in the same manner as in Example 1 except that a Ti-6Al-7Nb alloy powder having an average particle size of 25 μm was used instead of the Ti-6Al-4V alloy powder.
Then, the obtained titanium sintered body was cut, and the cut surface was buffed.

Next, the polished surface was observed with an electron microscope, and the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were determined, respectively. The results are shown in Table 3.

(Examples 14 to 18)
The same as in Example 13 except that the production conditions were changed so that the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were the values shown in Table 3, respectively. To obtain a titanium sintered body.

(Comparative Examples 9 to 12)
The same as in Example 13 except that the production conditions were changed so that the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were the values shown in Table 3, respectively. To obtain a titanium sintered body.

(Reference example 3)
First, a molten material of Ti-6Al-7Nb was prepared.

Next, the obtained molten material was cut, and the cut surface was buffed.
Next, the polished surface was observed with an electron microscope, and the average particle size of the α phase, the area ratio occupied by the α phase and the β phase, and the average aspect ratio of the α phase were determined, respectively. The results are shown in Table 3.

2. Evaluation of Titanium Sintered 2.1 Oxygen Content First, the oxygen content of the titanium sintered body of each example and comparative example and the titanium molten material of each reference example was measured by an oxygen-nitrogen simultaneous analyzer (manufactured by LECO). , TC-136). The measurement results are shown in Tables 1 to 3.

2.2 Vickers hardness Next, the Vickers hardness of the surfaces of the titanium sintered body of each example and each comparative example and the titanium molten material of each reference example was measured according to the method specified in JIS Z 2244: 2009. The measurement results are shown in Tables 1 to 3.

2.3 Average particle size of titanium oxide particles Next, the polished surfaces of the titanium sintered bodies of each example and each comparative example and the titanium molten material of each reference example were observed with an electron microscope. Then, the titanium oxide particles were identified in the observation image, and the average particle size thereof was calculated. The calculation results are shown in Tables 1 to 3.

2.4 Crystal structure analysis by X-ray diffraction method Next, the titanium sintered body of Example 1 was subjected to crystal structure analysis by X-ray diffraction method under the measurement conditions shown below.

<Measurement conditions for crystal structure analysis by X-ray diffraction method>
・ X-ray source: Cu-Kα ray ・ Tube voltage: 30 kV
・ Tube current: 20mA
The obtained X-ray diffraction spectrum is shown in FIG.

As is clear from FIG. 5, the X-ray diffraction spectrum obtained for the titanium sintered body of Example 1 shows the peak of the reflection intensity due to the α phase (α-Ti) and the reflection intensity due to the β phase (β-Ti). It was found that it contained the peak of. Therefore, when 2θ is based on the peak value of the reflection intensity due to the plane orientation (100) α-Ti located near 35.3 °, the plane orientation (110) β-Ti where 2θ is located near 39.5 ° is used as a reference. The ratio (peak ratio) of the peak value of the reflection intensity according to the above to the standard was calculated. Further, the same calculation was performed on the titanium sintered bodies of Examples 2 to 18 and Comparative Examples 1 to 3, 5 to 7, 9 to 11 and the titanium molten materials of Reference Examples 1 to 3. The calculation results of the peak ratio are shown in Tables 1 to 3. In the titanium sintered bodies of Comparative Examples 4, 8 and 12, peaks other than the α phase and the β phase were also conspicuous, so that it was difficult to calculate the peak ratio.

2.5 Mirror surface Next, the polished surfaces of the titanium sintered bodies of each example and each comparative example and the titanium molten material of each reference example were visually observed. Then, the mirror surface property of the polished surface was evaluated against the following evaluation criteria. The evaluation results are shown in Tables 1 to 3.

<Evaluation criteria for mirroring of polished surface>
⊚: The polished surface has a very high mirror surface (the aesthetic appearance is particularly good).
◯: The mirror surface of the polished surface is slightly high (the aesthetic appearance is slightly good).
Δ: The mirror surface of the polished surface is slightly low (the aesthetic appearance is slightly poor).
X: The mirror surface of the polished surface is very low (the aesthetic appearance is poor).

2.6 Relative Density Next, the relative densities of the titanium sintered bodies of each example and each comparative example and the titanium molten lumber of each reference example were calculated according to the method specified in JIS Z 2501: 2000. The calculation results are shown in Tables 1 to 3.

2.7 Abrasion resistance Next, the surface abrasion resistance of the titanium sintered body of each example and each comparative example and the titanium molten material of each reference example was evaluated. Specifically, first, the surface of the titanium sintered body was buffed. Next, the polished surface was subjected to a wear test according to the wear test method of the fine ceramics by the ball-on-disk method specified in JIS R 1613 (2010), and the amount of wear of the disk-shaped test piece was measured. The measurement conditions are as follows.

<Measurement conditions for specific wear amount>
-Material of spherical test piece: High carbon chrome bearing steel (SUJ2)
-Spherical test piece size: 6 mm in diameter
-Material of disk-shaped test piece: Sintered body of each example and each comparative example and molten material of each reference example-Size of disk-shaped test piece: diameter 35 mm, thickness 5 mm
・ Load size: 10N
・ Sliding speed: 0.1m / s
・ Sliding circle diameter: 30 mm
・ Sliding distance: 50m

Then, the amount of wear obtained for the titanium molten material of Reference Example 1 was set to 1, and the relative value of the amount of wear obtained for the titanium sintered bodies of each Example and each Comparative Example shown in Table 1 was calculated.

Similarly, the amount of wear obtained for the titanium molten material of Reference Example 2 was set to 1, and the relative value of the amount of wear obtained for the titanium sintered bodies of each Example and each Comparative Example shown in Table 2 was calculated.

Further, similarly, the amount of wear obtained for the titanium molten material of Reference Example 3 was set to 1, and the relative value of the amount of wear obtained for the titanium sintered bodies of each Example and each Comparative Example shown in Table 3 was calculated. ..

Then, the calculated relative value was evaluated against the following evaluation criteria. The evaluation results are shown in Tables 1 to 3.

<Evaluation criteria for wear amount>
A: Very little wear (relative value is less than 0.5)
B: The amount of wear is small (relative value is 0.5 or more and less than 0.75)
C: The amount of wear is slightly small (relative value is 0.75 or more and less than 1).
D: Slightly large amount of wear (relative value is 1 or more and less than 1.25)
E: Large amount of wear (relative value is 1.25 or more and less than 1.5)
F: Very large amount of wear (relative value is 1.5 or more)

2.8 Tensile strength Next, the tensile strength of the titanium sintered body of each example and each comparative example, the titanium molten material of each reference example, and the like were measured. The tensile strength was measured according to the metal material tensile test method specified in JIS Z 2241 (2011).

Then, the tensile strength obtained for the titanium molten material of Reference Example 1 was set to 1, and the relative value of the tensile strength obtained for the titanium sintered bodies of each Example and each Comparative Example shown in Table 1 was calculated.

Similarly, the tensile strength obtained for the titanium molten material of Reference Example 2 was set to 1, and the relative value of the tensile strength obtained for the titanium sintered bodies of each Example and each Comparative Example shown in Table 2 was calculated. ..

Further, similarly, the tensile strength obtained for the titanium molten material of Reference Example 3 is set to 1, and the relative value of the tensile strength obtained for the titanium sintered body of each Example and each Comparative Example shown in Table 3 is set to 1. Calculated.

Then, the obtained relative values were evaluated against the following evaluation criteria. The evaluation results are shown in Tables 1 to 3. Regarding the tensile strength, in addition to the above test specimens, SUS316L sintered body, ASTM F75 (Co-28% Cr-6% Mo alloy) cast material and sintered body, and α-Ti sintered body are also used. , Evaluated as reference examples a to d (Table 1). In addition, Reference Example d was also evaluated in the same manner as in 2.1, 2.2 and 2.5 to 2.7 described above.

<Evaluation criteria for tensile strength>
A: The tensile strength is very large (relative value is 1.09 or more).
B: High tensile strength (relative value is 1.06 or more and less than 1.09)
C: Tensile strength is slightly large (relative value is 1.3 or more and less than 1.06)
D: Tensile strength is slightly small (relative value is 1 or more and less than 1.03)
E: Tensile strength is small (relative value is 0.97 or more and less than 1)
F: Tensile strength is very small (relative value is less than 0.97)

2.9 Nominal strain at break (break elongation)
Next, the elongation at break was measured for the titanium sintered body of each example and each comparative example, the titanium molten material of each reference example, and the like. The elongation at break was measured according to the metal material tensile test method specified in JIS Z 2241 (2011).

Then, the obtained elongation at break was evaluated against the following evaluation criteria. The evaluation results are shown in Tables 1 to 3. Regarding elongation at break, in addition to the above test specimens, SUS316L sintered body, ASTM F75 (Co-28% Cr-6% Mo alloy) cast material and sintered body, and α-Ti sintered body were also used. It was evaluated as reference examples a to d (Table 1).

<Evaluation criteria for elongation at break>
A: Very large breaking elongation (0.15 or more)
B: Large breaking elongation (0.125 or more and less than 0.15)
C: Slightly large elongation at break (0.10 or more and less than 0.125)
D: Slightly small elongation at break (0.075 or more and less than 0.10)
E: Small elongation at break (0.050 or more and less than 0.075)
F: Very small elongation at break (less than 0.050)

2.10 Cytotoxicity test Next, a cytotoxicity test was conducted on a test piece composed of a titanium sintered body of each Example and each Comparative Example and a titanium molten material of each Reference Example. The cytotoxicity test was performed according to the cytotoxicity test specified in ISO 10993-5: 2009. Specifically, when the average value of the number of colonies in the control group is set to 100% by the colonization method by the direct contact method, the ratio of the number of cells directly seeded to the test piece to the number of colonies in the control group (colony formation). The rate [%]) was calculated. The test conditions are as follows.

-Cell line: V97 cells-Medium: MEM10 medium-Negative control material (negative control): High-density polyethylene film-Positive control material (positive control): Polyurethane film containing 0.1% zinc diethyldithiocarbamate-Control group (control) : Number of colonies of cells seeded directly in the medium

Next, the cytotoxicity of each test body was evaluated by classifying the obtained colony formation rate according to the following evaluation criteria. The evaluation results are shown in Tables 1 to 3. Regarding the cytotoxicity test, in addition to the above test specimens, SUS316L sintered body, ASTM F75 (Co-28% Cr-6% Mo alloy) sintered body, and α-Ti sintered body are also referred to as reference example a. , C, d (Table 1).

<Cytotoxicity evaluation criteria>
A: Colony formation rate is 90% or more B: Colony formation rate is 80% or more and less than 90% C: Colony formation rate is less than 80%

As is clear from Tables 1 to 3, the titanium sintered body of each example was found to have excellent wear resistance. Further, it was confirmed that the titanium sintered body of each example had high relative density and tensile strength, and was excellent in mirror surface property of the polished surface.

Here, an electron microscope image of a cross section of the titanium sintered body of Comparative Example 2 is shown in FIG. From FIG. 11, it can be seen that in the titanium sintered body of Comparative Example 2, the α phase has an elongated shape, that is, a shape having a large anisotropy.

Further, an electron microscope image of a cross section of the titanium molten material of Reference Example 1 is shown in FIG. From FIG. 12, it can be seen that the titanium molten lumber of Reference Example 1 has a shape having a large anisotropy, although the particle size of the α phase is relatively small.

1 ... Titanium sintered body, 2 ... α phase, 3 ... β phase, 4 ... Nozzle vane, 5 ... Impeller wheel, 6 ... Compressor blade, 11 ... Watch case, 12 ... Bezel, 41 ... Shaft, 42 ... Wing , 43 ... Axis, 44 ... Center hole, 45 ... Flat part, 46 ... Flange part, 47 ... Chamfer, 48 ... Chamfer, 54 ... Hub part, 55 ... Wing part, 61 ... Inner rim, 62 ... Outer rim, 63 ... Wing part, 112 ... Case body, 114 ... Band mounting part, 530 ... Rotating shaft, 541 ... Through hole, 551 ... Long wing part, 552 ... Short wing part, θ ... Angle

Claims (8)

Composed of materials containing titanium,
It contains the α phase and β phase of titanium as a crystal structure.
The area ratio occupied by the α phase in the cross section is 78 % or more and 99.8% or less.
The average particle size of the α phase in the cross section is 5 μm or more and 30 μm or less.
The oxygen content is 3200 ppm or more and 5500 ppm or less in terms of mass ratio.
A titanium sintered body having a surface Vickers hardness of 300 or more and 500 or less. The titanium sintered body according to claim 1, wherein the average aspect ratio of the α phase is 1 or more and 3 or less. In the X-ray diffraction spectrum acquired by the X-ray diffraction method, the peak value of the reflection intensity due to the plane orientation (110) of the β phase is 5% or more of the peak value of the reflection intensity due to the plane orientation (100) of the α phase. The titanium sintered body according to claim 2, which is 60% or less. The titanium sintered body according to any one of claims 1 to 3, which contains particles containing titanium oxide as a main component. The titanium sintered body according to claim 4, wherein the average particle size of the particles is 0.5 μm or more and 20 μm or less. The titanium sintered body according to any one of claims 1 to 5, wherein the relative density is 99% or more. An ornament comprising the titanium sintered body according to any one of claims 1 to 6. A heat-resistant component comprising the titanium sintered body according to any one of claims 1 to 6.

Images