TITANIUM BASED PRODUCT AND METHOD FOR MANUFACTURING THE SAME

Abstract

A method for manufacturing a titanium based product includes the following steps. The first step is providing a titanium hydride ingot. The next step is pre-sintering the titanium hydride ingot to dehydrogenate the titanium hydride ingot according to a first temperature control mode, so as to form a titanium ingot. The next step is machining the titanium ingot to form a titanium semi-product having a desired shape. The last step is post-sintering the titanium semi-product according to a second temperature control mode that is different from the first temperature control mode, so as to form the titanium based product.

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the benefit of priority to Taiwan Patent Application No. 107129622, filed on Aug. 24, 2018. The entire content of the above identified application is incorporated herein by reference.

Some references, which may include patents, patent applications and various publications, may be cited and discussed in the description of this disclosure. The citation and/or discussion of such references is provided merely to clarify the description of the present disclosure and is not an admission that any such reference is “prior art” to the disclosure described herein. All references cited and discussed in this specification are incorporated herein by reference in their entireties and to the same extent as if each reference was individually incorporated by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates to a titanium based product and a method for manufacturing the same, and more particularly to a two-stage sintered titanium based product and a method for manufacturing the same.

BACKGROUND OF THE DISCLOSURE

Titanium and its alloys have many advantages such as stable chemical properties, high strength, low weight, high temperature resistance, high corrosion resistance, and high biocompatibility. In recent years, the application industries of titanium alloys widely include automobile, ship, medicine, entertainment equipment, and mobile electronic device.

The main methods for shaping titanium and its alloys include casting, forging and powder metallurgy. Although the casting and forging methods have simpler operations, it is difficult to produce products having complex structures and shapes therewith, and the products produced thereby may have poor precision. The powder metallurgy method is a technique that uses a powder material to form a metal product by shaping and sintering. In contrast, the powder metallurgy method can solve shaping problems associated with components with complex shapes. However, the conventional powder metallurgy method is provided with only one sintering step for the formation of the titanium or titanium alloy material. The one-stage sintered titanium or titanium alloy material is difficult to be precisely processed. In addition, the equipment used to process the one-stage sintered titanium or titanium alloy material may have a high wear rate and thus result in a high processing cost.

Therefore, there is an urgent need to reduce the processing difficulty and cost of the titanium and titanium alloy products having required mechanical properties.

SUMMARY OF THE DISCLOSURE

In response to the above-referenced technical inadequacies, the present disclosure provides a method for manufacturing a titanium based product, which can overcome the problems associated with the shaping of titanium or titanium alloy products, and a titanium based product manufactured by the method.

In one aspect, the present disclosure provides a method for manufacturing a titanium based product, including: providing a titanium hydride ingot; pre-sintering the titanium hydride ingot to dehydrogenate the titanium hydride ingot according to a first temperature control mode, so as to form a titanium ingot; machining the titanium ingot to form a titanium semi-product having a desired shape; and post-sintering the titanium semi-product according to a second temperature control mode that is different from the first temperature control mode, so as to form the titanium based product.

In one aspect, the present disclosure provides a titanium based product manufactured by the aforesaid method. The titanium based product has a Vickers hardness between 200 HV and 250 HV, a tensile strength between 600 MPa and 650 MPa, and a yield strength between 500 MPa and 550 MPa.

One of the advantages of the present disclosure is that the method of the present disclosure, which pre-sinters the titanium hydride ingot according to a first temperature control mode, then machines the titanium ingot formed, and subsequently post-sinters the titanium semi-product according to a second temperature control mode formed, can reduce the wear rate of the processing equipment, thereby reducing the cost.

These and other aspects of the present disclosure will become apparent from the following description of the embodiment taken in conjunction with the following drawings and their captions, although variations and modifications therein may be affected without departing from the spirit and scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from the following detailed description and accompanying drawings.

FIG. 1 is a flowchart of a method for manufacturing a titanium based product of the present disclosure.

FIG. 2 is a schematic view illustrating a step S1 of the method for manufacturing a titanium based product of the present disclosure.

FIG. 3 is a schematic view illustrating a step S2 of the method for manufacturing a titanium based product of the present disclosure.

FIG. 4 is a schematic view illustrating a step S3 of the method for manufacturing a titanium based product of the present disclosure.

FIGS. 5 and 6 are schematic views illustrating a step S4 of the method for manufacturing a titanium based product of the present disclosure.

FIG. 7 is a schematic view illustrating a step S5 of the method for manufacturing a titanium based product of the present disclosure.

FIG. 8 shows a first temperature control mode used in the step S2 of the method for manufacturing a titanium based product of the present disclosure.

FIG. 9 shows a second temperature control mode used in the step S4 of the method for manufacturing a titanium based product of the present disclosure.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present disclosure is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Like numbers in the drawings indicate like components throughout the views. As used in the description herein and throughout the claims that follow, unless the context clearly dictates otherwise, the meaning of “a”, “an”, and “the” includes plural reference, and the meaning of “in” includes “in” and “on”. Titles or subtitles can be used herein for the convenience of a reader, which shall have no influence on the scope of the present disclosure.

The terms used herein generally have their ordinary meanings in the art. In the case of conflict, the present document, including any definitions given herein, will prevail. The same thing can be expressed in more than one way. Alternative language and synonyms can be used for any term(s) discussed herein, and no special significance is to be placed upon whether a term is elaborated or discussed herein. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms is illustrative only, and in no way limits the scope and meaning of the present disclosure or of any exemplified term. Likewise, the present disclosure is not limited to various embodiments given herein. Numbering terms such as “first”, “second” or “third” can be used to describe various components, signals or the like, which are for distinguishing one component/signal from another one only, and are not intended to, nor should be construed to impose any substantive limitations on the components, signals or the like.

Referring to FIG. 1, which is to be read in conjunction with FIGS. 2 to 6, the present disclosure provides a method for manufacturing a titanium based product including the following steps. The first step (i.e., step S1) is providing a titanium hydride ingot. The next step (i.e., step S2) is pre-sintering the titanium hydride ingot according to a first temperature control mode to form a titanium ingot. The next step (i.e., step S3) is machining the titanium ingot to form a titanium semi-product having a desired shape. The last step (i.e., step S4) is post-sintering the titanium semi-product to form a titanium based product. The titanium based product can be a casing or component of an electronic device, but is not limited thereto.

Reference is made to FIG. 2, in the step S1, the titanium hydride ingot 102 can be formed from a titanium hydride powder 100. Specifically speaking, the titanium hydride powder 100 can have a predetermined particle size, and can be put into a specific mold and dry-pressed at a suitable pressure to form the titanium hydride ingot 102 with a specific shape and size. According to particular requirements, a predetermined amount of other metal (e.g., aluminum and vanadium) or metal precursor powders can be mixed into the titanium hydride powder 100.

In the present embodiment, the titanium hydride powder has an average particle size between 3 μm and 500 μm, and preferably between 100 μm and 300 μm. If the average particle size is less than 1 μm, the titanium hydride powder may spontaneously ignite. If the average particle size is greater than 400 μm, the titanium hydride powder is difficult to be densely pressed, so that the titanium hydride ingot 102 does not have a required density.

The titanium hydride powder can be made by the following steps. Firstly, a titanium sponge is hydrogenated under a vacuum condition and an atmosphere of a substantially pure hydrogen gas (purity >99.9%) to form a titanium hydride sponge. The titanium sponge is preferably a zero-order titanium sponge that has a low oxygen-content. Subsequently, the titanium hydride sponge is crushed by being ball-milled under a protective atmosphere, and the titanium hydride particles thus obtained are classified by particle size.

Reference is made to FIG. 3, in the step S2, the titanium hydride ingot 102 is placed in a chamber of a sintering device and the chamber is maintained at a vacuum degree of about 2×10⁻⁴ torr by pumping. Subsequently, the titanium hydride ingot 102 is pre-sintered (i.e., sintered for the first time) according to a first temperature control mode. During this process, the titanium hydride ingot 102 is dehydrogenated to form a high-purity titanium ingot 104. That is to say, a dehydrogenation reaction of the titanium hydride ingot 102 is carried out during this process. In other embodiments, the titanium hydride ingot 102 can be pre-sintered to form a sintered body, and the sintered body can proceed to be dehydrogenated under a vacuum condition.

As shown in FIG. 8, the first temperature control mode is exemplified as gradually increasing a pre-sintering temperature up to 800-900° C. at a predetermined heating rate, then maintaining the pre-sintering temperature for 3 hours, and finally cooling the pre-sintering temperature to the room temperature. In the present embodiment, the titanium ingot 104 formed in the step S2 has a line shrinkage rate between 6% and 9% with respect to the titanium hydride ingot 102, preferably 8.5%, a density between 3.5 g/cm³ and 4.1 g/cm³, preferably 3.71 g/cm³, a porosity between 15% and 20%, preferably 17.5%, and a Vickers hardness between 90 HV and 110 HV, preferably 108 HV.

Reference is made to FIG. 4 which is to be read in conjunction with FIG. 3, in the step S3, a machine tool (not numbered) such as a milling cutter can be used to change the shape and size of the titanium ingot 104, so as to form a titanium semi-product 106 that corresponds in shape and size to the final product before the post-sintering begins. However, the machine tool used in the step S3 is merely an example and is not meant to limit the present disclosure. It should be noted that, the titanium ingot 104 has a relatively low hardness and density, so that the wear rate of the processing equipment can be reduced, thereby reducing costs.

Reference is made to FIGS. 5 and 6, in the step S4, the titanium semi-product 106 is placed in a chamber of the sintering device and the chamber is maintained at a vacuum degree of about 2×10⁻⁴ torr by pumping. Subsequently, the titanium semi-product 106 is pre-sintered (i.e., sintered for the second time) according to a second temperature control mode that is different from the first temperature control mode, so as to form a titanium based product 108 having a high purity, high density and low oxygen content.

As shown in FIG. 9, the second temperature control mode is exemplified as gradually increasing a post-sintering temperature up to 1200-1300° C. at a predetermined heating rate, then maintaining the post-sintering temperature for 3 hours, and finally cooling the pre-sintering temperature to the room temperature. In the present embodiment, the titanium based product 108 formed in the step S4 has a line shrinkage rate between 13% and 16% with respect to the titanium hydride ingot 102, preferably 14.5%, a density of about 4.45 g/cm³, a porosity of about 0.4%, and a Vickers hardness between 200 HV and 250 HV, preferably 240 HV.

It should be noted that, if predetermined amounts of other metal powders such as 6 wt % of an aluminum powder and 4 wt % of a vanadium powder are mixed into the titanium hydride powder 100 in the step S1, the titanium based product 108 obtained by the step S4 would contain other metal components except for titanium.

Referring now to FIG. 1 along with FIG. 7, the method of the present disclosure can further include a step (step S5) of modifying an appearance of the titanium based product 108. In the present embodiment, surface trimming, polishing, lead angle chamfering processes, and etc., can be performed on the titanium based product 108 to meet precision requirements in actual use. However, the aforesaid processes are merely examples and are not meant to limit the present disclosure. After modifying the appearance of the titanium based product 108, the method of the present disclosure can further include a step (step S6) of precisely machining the modified titanium based product 108. In the present embodiment, the modified titanium based product 108 can be formed with through holes H, but is not limited thereto, so as to increase its structural complexity.

One of the advantages of the present disclosure is that the method of the present disclosure, which pre-sinters the titanium hydride ingot according to a first temperature control mode, then machines the titanium ingot formed, and subsequently post-sinters the titanium semi-product according to a second temperature control mode formed, can reduce the wear rate of the processing equipment, thereby reducing costs.

Furthermore, by using the aforesaid technical solution, the process time can be reduced and the processing precision and structural complexity of the titanium based product can be increased.

In addition, the titanium based product of the present disclosure, compared with the conventional titanium substrate, has more excellent mechanical properties. The comparison between the titanium based product of the present disclosure and the commercial titanium substrates is shown in Table 1.

	TABLE 1
	Titanium
	based	Ti	Ti	MIM Ti
	product	Gr.3	Gr.4	BASF
Vickers hardness (HV)	240	150	165	160-240
Density (g/cm3)	4.45	4.51	4.51	>4.2
tensile strength (MPa)	641	380	550	550
yield strength (MPa)	511	450	480	480
ductility (%)	11	18	15	>5
elastic modulus (GPa)	105	105	105	105

As shown in Table 1, the titanium based product of the present disclosure, compared with the commercial titanium substrate, has an improved hardness, tensile strength, and yield strength. The tensile strength of the titanium based product is between 600 MPa and 650 MPa and the yield strength of the titanium based product is between 500 MPa and 550 MPa.

The foregoing description of the exemplary embodiments of the disclosure has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.

The embodiments were chosen and described in order to explain the principles of the disclosure and their practical application so as to enable others skilled in the art to utilize the disclosure and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present disclosure pertains without departing from its spirit and scope.

Claims

1. A method for manufacturing a titanium based product, comprising:

providing a titanium hydride ingot;

pre-sintering the titanium hydride ingot to dehydrogenate the titanium hydride ingot according to a first temperature control mode, so as to form a titanium ingot;

machining the titanium ingot to form a titanium semi-product having a desired shape; and

post-sintering the titanium semi-product according to a second temperature control mode that is different from the first temperature control mode, so as to form the titanium based product.

2. The method according to claim 1, further comprising modifying an appearance of the titanium based product after the step of post-sintering the titanium semi-product.

3. The method according to claim 2, further comprising precisely machining the modified titanium based product after the step of modifying the appearance of the titanium based product.

4. The method according to claim 1, wherein the step of providing the titanium hydride ingot includes dry-pressing a titanium hydride powder to form the titanium hydride ingot.

5. The method according to claim 1, wherein the first temperature control mode is gradually increasing a pre-sintering temperature up to 800-900° C. at a predetermined heating rate and then maintaining the pre-sintering temperature for 3 hours.

6. The method according to claim 5, wherein the second temperature control mode is gradually increasing a post-sintering temperature up to 1200-1300° C. at the predetermined heating rate and then maintaining the post-sintering temperature for 3 hours.

7. The method according to claim 6, wherein the predetermined heating rate is 5° C./min.

8. The method according to claim 1, wherein the titanium ingot has a line shrinkage rate between 6% and 9% with respect to the titanium hydride ingot, and the titanium based product has a line shrinkage rate between 13% and 16% with respect to the titanium hydride ingot.

9. The method according to claim 1, wherein the titanium ingot has a density between 3.5 g/cm3 and 4.1 g/cm3, and the titanium based product has a density of 4.45 g/cm3.

10. The method according to claim 1, wherein the titanium ingot has a porosity between 15% and 20%, and the titanium based product has a porosity of 0.4%.

11. The method according to claim 1, wherein the titanium ingot has a Vickers hardness between 90 HV and 110 HV, and the titanium based product has a Vickers hardness between 200 HV and 250 HV.

12. A titanium based product manufactured by the method according to claim 1, the titanium based product having a Vickers hardness between 200 HV and 250 HV, a tensile strength between 600 MPa and 650 MPa, and a yield strength between 500 MPa and 550 MPa.