阅读说明：本技术 具有均一横纵向性能的钛合金制件及其制备方法 (Titanium alloy part with uniform transverse and longitudinal properties and preparation method thereof ) 是由 计霞 楚瑞坤 段修涛 陈志茹 汪承杰 高桦 许停停 秦贤 邹荣堃 于 2019-10-23 设计创作，主要内容包括：本申请提供了一种具有均一横纵向性能的钛合金制件及其制备方法。该方法包括：通过在激光选区熔化成型过程中,使钛合金制件的至少一部分马氏体转变为α相和/或β相,以制备钛合金制件；及通过热处理对钛合金制件进行均一化处理,进一步提高横纵向一致性。本申请的技术方案可获得具有均一横纵向性能的钛合金制件,其横向、纵向的强度及延伸率差异在5％内,比较一致。(The application provides a titanium alloy part with uniform transverse and longitudinal properties and a preparation method thereof. The method comprises the following steps: preparing a titanium alloy article by converting at least a portion of the martensite of the titanium alloy article to the alpha phase and/or the beta phase during the selective laser melting formation; and carrying out homogenization treatment on the titanium alloy workpiece through heat treatment, and further improving the transverse and longitudinal consistency. According to the technical scheme, the titanium alloy part with uniform transverse and longitudinal properties can be obtained, and the transverse and longitudinal strength and elongation rate difference is within 5%, so that the transverse and longitudinal strength and elongation rate difference are relatively consistent.)

1. A method of making a titanium alloy article having uniform transverse and longitudinal properties, comprising:

preparing the titanium alloy article by converting at least a portion of the martensite of the titanium alloy article to an alpha phase and/or a beta phase during a laser selective melt-forming process;

and carrying out homogenization treatment on the titanium alloy workpiece through heat treatment.

2. The method of claim 1, wherein the process parameters of the selective laser melting molding are as follows: the laser power is 280-330W, the scanning speed is 900-1200mm/s, the powder layer thickness is 20-40 μm, the spot diameter is 0.06-0.25mm, the laser overlap is 0-0.2mm, and the substrate temperature is 150-210 ℃.

3. The method of claim 1, wherein the heat treatment is a vacuum heat treatment.

4. The method of claim 3, wherein the vacuum degree of the vacuum heat treatment is 1.0 x 10^-1-6.67×10^-2Pa。

5. The method as claimed in claim 3, wherein the temperature of the vacuum heat treatment is 800-925 ℃ and the holding time is 2-4 h.

6. The method of claim 3, wherein the vacuum heat treated titanium alloy article is cooled by air cooling.

7. The method as claimed in claim 1, wherein the sphericity is not less than 88% and the bulk density is 2.00-2.45g/cm³The tap density is 2.50-2.80g/cm³And carrying out laser selective melting molding on the titanium alloy powder with the Hall flow rate of less than or equal to 50s/50g, the hollow powder rate of less than or equal to 0.5 percent and the inclusion of less than or equal to 0.5 percent.

8. The method of claim 1, wherein the selective laser melting is performed using titanium alloy powder having a D10 particle size of 18-22 μm, a D50 particle size of 26-35 μm, and a D90 particle size of 45-55 μm.

9. A titanium alloy article having uniform transverse longitudinal properties produced by the method of any one of claims 1 to 8.

Technical Field

The application belongs to the technical field of titanium alloys, and particularly relates to a titanium alloy part with uniform transverse and longitudinal properties and a preparation method thereof, in particular to a special-shaped titanium alloy part with uniform transverse and longitudinal properties and a preparation method thereof.

Background

Alloy parts are widely applied in various industries, wherein the use of special-shaped components is increased. The traditional mechanical processing is difficult to prepare various special-shaped components, and the laser selective melting forming technology (3D printing) just makes up for the defect, so that products with almost any shapes can be manufactured. However, the alloys manufactured by the current selective laser melting method often have obvious differences of transverse and longitudinal properties, for example, titanium alloys such as TC4, TA15, TA17, TA1, TC21 and the like have high strength and low elongation rate of samples perpendicular to the growth direction and low strength and high elongation rate of samples parallel to the growth direction under the current process parameters, which inevitably causes the differences of transverse and longitudinal properties of products, and the differences of transverse and longitudinal properties cannot be twisted at all by subsequent annealing heat treatment.

The isotropy of the metal-based alloy is related to the establishment of the allowable design value, and if the alloy has obvious anisotropy, the alloy piece is likely to cause material failure phenomena such as product damage and the like due to the low performance values of certain orientations in the alloy piece. Especially for the special-shaped structural parts, the structural parts are always subjected to multi-directional load during the use process, so that the improvement of the anisotropy of the alloy is necessary.

Disclosure of Invention

The invention aims to improve the structure form of the alloy in the forming process so as to reduce the difference between the transverse direction and the longitudinal direction, and further, the transverse direction and the longitudinal direction of the alloy are finally consistent through a heat treatment mode.

One aspect of the present application provides a method of making a titanium alloy article having uniform transverse longitudinal properties, comprising:

preparing the titanium alloy article by converting at least a portion of the martensite of the titanium alloy article to an alpha phase and/or a beta phase during selective laser melting; and

and carrying out homogenization treatment on the titanium alloy workpiece through heat treatment.

In some embodiments of the present application, the process parameters of the selective laser melting molding are as follows: the laser power is 280-330W, the scanning speed is 900-1200mm/s, the powder layer thickness is 20-40 μm, the spot diameter is 0.06-0.25mm, the laser overlap is 0-0.2mm, and the substrate temperature is 150-210 ℃.

In some embodiments of the present application, the heat treatment is a vacuum heat treatment.

In some embodiments of the present application, the vacuum degree of the vacuum heat treatment is 1.0 × 10^-1-6.67×10^-2Pa。

In some embodiments of the present application, the temperature of the vacuum heat treatment is 800-.

In some embodiments of the present application, the vacuum heat treated titanium alloy article is cooled by air cooling.

In some embodiments of the present application, a sphericity of 88% or more and a bulk density of 2.00-2.45g/cm is used³The tap density is 2.50-2.80g/cm³And carrying out laser selective melting molding on the titanium alloy powder with the Hall flow rate of less than or equal to 50s/50g, the hollow powder rate of less than or equal to 0.5 percent and the inclusion of less than or equal to 0.5 percent.

In some embodiments of the present application, the selective laser melting molding is performed using titanium alloy powder having a D10 particle size of 18-22 μm, a D50 particle size of 26-35 μm, and a D90 particle size of 45-55 μm.

In another aspect of the present application, there is provided a titanium alloy article having uniform transverse longitudinal properties produced by the above method.

According to the technical scheme, the titanium alloy part with uniform transverse and longitudinal properties can be obtained, and the transverse and longitudinal strength and elongation rate difference is within 5%, so that the transverse and longitudinal strength and elongation rate difference are relatively consistent.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

FIG. 1 is a flow chart of a preferred process for making titanium alloy articles according to the present application.

FIG. 2 is a metallographic representation of a photograph of a green article of titanium alloy obtained from example 1 after printing, in which (1) is the XZ plane and (2) is the XY plane.

Fig. 3 shows a gold phase diagram of the titanium alloy article finally obtained in example 1, in which (1) is an XZ plane and (2) is an XY plane.

FIG. 4 is a metallographic representation of a gold phase of a titanium alloy green part obtained after printing obtained in comparative example 1, wherein (1) is an XZ plane and (2) is an XY plane.

FIG. 5 shows the gold phase diagram of the final titanium alloy article of comparative example 1, wherein (1) is the XZ plane and (2) is the XY plane.

FIG. 6 is a metallographic representation of a photograph of a green article of titanium alloy obtained from example 2 after printing, in which (1) is the XZ plane and (2) is the XY plane.

Fig. 7 shows a gold phase diagram of a titanium alloy article finally obtained in example 2, in which (1) is an XZ plane and (2) is an XY plane.

FIG. 8 is a schematic diagram showing the gold phase of the final titanium alloy article of comparative example 2, wherein (1) is an XZ plane and (2) is an XY plane.

Fig. 9 shows a gold phase diagram of a titanium alloy article finally obtained in example 3, in which (1) is an XZ plane and (2) is an XY plane.

FIG. 10 shows the gold phase diagram of the final titanium alloy article of comparative example 3, wherein (1) is the XZ plane and (2) is the XY plane.

Detailed Description

The following detailed description of the present application, taken in conjunction with the accompanying drawings and examples, is provided to enable the aspects of the present application and its advantages to be better understood. However, the specific embodiments and examples described below are for illustrative purposes only and are not limiting of the present application.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The following disclosure provides many different embodiments or examples for implementing different features of the application. In order to simplify the disclosure of the present application, specific example components and arrangements are described below. Of course, they are merely examples and are not intended to limit the present application. Moreover, the present application may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, examples of various specific processes and materials are provided herein, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and are not to be construed as limiting the present application.

The transverse and longitudinal properties refer to transverse and longitudinal mechanical properties (such as strength and elongation) of a titanium alloy product.

The technical scheme for preparing the titanium alloy part with uniform transverse and longitudinal properties provided by the application is as follows:

preparing a titanium alloy article by converting at least a portion of the martensite of the titanium alloy article to an alpha phase and/or a beta phase during a selective laser melting formation process; and

and carrying out homogenization treatment on the titanium alloy workpiece through heat treatment.

According to the method, the titanium alloy part is prepared by a selective laser melting forming technology, and at least a part of martensite in the titanium alloy part is converted into an alpha phase and/or a beta phase in the forming process, so that the internal organization structure of the titanium alloy part is improved, and the difference of transverse and longitudinal properties of the titanium alloy is reduced.

Furthermore, the prepared titanium alloy part is melted and formed through selective laser, and then heat treatment is carried out, so that the internal organization structure of the titanium alloy part is further more uniform, and more consistent transverse and longitudinal performance is obtained.

In the application, the technological parameters of selective laser melting molding directly influence the phase change of the internal organization structure of the titanium alloy part. In the preferred embodiment of the present application, the process parameters of selective laser melting molding are as follows: the laser power is 280-330W, the scanning speed is 900-1200mm/s, the powder layer thickness is 20-40 μm, the spot diameter is 0.06-0.25mm, the laser overlap is 0-0.2mm, and the substrate temperature is 150-210 ℃. Within this range, sufficient heat transfer from the formed layer to transform at least a portion of the martensite to the alpha phase and/or the beta phase is ensured when the next layer is printed.

In the application, the heat treatment mode and the heat treatment process parameters directly influence the homogenization of the internal tissue structure of the titanium alloy workpiece. In the preferred embodiment of the present application, the homogenization treatment is performed by means of vacuum heat treatment. More preferably still, the first and second liquid crystal compositions are,the vacuum degree of the vacuum heat treatment is 1.0 x 10^-1-6.67×10^-2Pa. Titanium alloy is an active metal, and is in contact with oxygen during heat treatment at a temperature of above 400 ℃, so that a compact alpha pollution layer is easily formed on the surface of the titanium alloy, and the alpha pollution layer can greatly reduce the plastic toughness of the titanium alloy, so that the vacuum degree is preferably strictly controlled during heat treatment.

Further preferably, the temperature of the vacuum heat treatment is 800-. After the heat treatment, the titanium alloy product is preferably cooled by air cooling.

The titanium alloy powder is subjected to selective laser melting molding to prepare a titanium alloy part, and the performance of the titanium alloy powder also has indirect influence on the performance of the final titanium alloy part, especially the particle size of the titanium alloy powder. In the preferred embodiment of the present application, titanium alloy powder having a D10 particle size of 18-22 μm, a D50 particle size of 26-35 μm, and a D90 particle size of 45-55 μm is used. More preferably, the titanium alloy powder used has a sphericity of 88% or more and a bulk density of 2.00 to 2.45g/cm³The tap density is 2.50-2.80g/cm³The Hall flow rate is less than or equal to 50s/50g, the hollow powder rate is less than or equal to 0.5 percent, and the inclusion is less than or equal to 0.5 percent. It should be noted that the titanium alloy powder used in the present application may be made by self or purchased, as long as the corresponding requirements are met.

FIG. 1 illustrates a preferred process for preparing titanium alloy articles according to the present application, comprising the following steps:

s1: and preparing titanium alloy powder.

The parameters of the titanium alloy powder were as follows: the particle size of D10 is 18-22 μm, the particle size of D50 is 26-35 μm, and the particle size of D90 is 45-55 μm; the sphericity is more than or equal to 88 percent, the apparent density is 2.00-2.45g/cm3, the tap density is 2.50-2.80g/cm3, the Hall flow rate is less than or equal to 50s/50g, the hollow powder rate is less than or equal to 0.5 percent, and the inclusion content is less than or equal to 0.5 percent.

S2: and (5) manufacturing a titanium alloy workpiece model.

And drawing a model of the titanium alloy workpiece by using three-dimensional drawing software, converting a three-dimensional digital model into two-dimensional slice data by using three-dimensional conversion two-dimensional data software to obtain two-dimensional slice data, and introducing the two-dimensional slice data into a system of laser selective melting molding equipment.

S3: and selective laser melting and forming.

Setting molding process parameters: the laser power is 280-330W, the scanning speed is 900-1200mm/s, the powder layer thickness is 20-40 μm, the spot diameter is 0.06-0.25mm, the laser overlap is 0-0.2mm, and the substrate temperature is 150-210 ℃. And then printing to obtain a titanium alloy blank workpiece.

S4: and (6) heat treatment.

And carrying out vacuum heat treatment on the titanium alloy blank part obtained after printing at the temperature of 800-. And cooling the titanium alloy workpiece in an air cooling mode after the heat treatment. And (5) obtaining the product.

The present application will be described with reference to specific examples. The values of the process conditions taken in the following examples are exemplary and ranges of values are provided as indicated in the foregoing summary, and reference may be made to conventional techniques for process parameters not specifically noted. The detection methods used in the following examples are all conventional in the industry.