CN114369744A - A kind of non-magnetic wide temperature range constant elasticity titanium alloy and preparation method thereof - Google Patents

Abstract

The invention relates to the field of metal materials, in particular to a non-magnetic wide temperature range constant elasticity titanium alloy and a preparation method thereof. The composition of the titanium alloy contains at least one β-stabilizing element, may contain one or two or more neutral elements, and may contain one or two or more α-stabilizing elements. The preparation method of the titanium alloy includes heat treatment, the heat treatment temperature is 250-550 DEG C, and the heat treatment time is 0.5-48 hours. The constant elasticity titanium alloy prepared by this method has a temperature coefficient of elastic modulus less than 20×10 ^‑6 /℃ in a wide temperature range, an elastic modulus at room temperature of 60 to 90 GPa, and a yield strength of more than 600 MPa, and has excellent comprehensive properties. The titanium alloy in the present invention belongs to non-magnetic materials, is not disturbed by the magnetic field of the actual use environment, can achieve constant elastic performance in a very wide temperature range, and the temperature coefficient of elastic modulus can be adjusted, and has excellent mechanical properties at the same time, The preparation method is simple, so it is a non-magnetic and constant elastic material with good application prospect.

Description

A kind of non-magnetic wide temperature range constant elasticity titanium alloy and preparation method thereof

technical field

The invention relates to the field of metal materials, in particular to a non-magnetic wide temperature range constant elasticity titanium alloy and a preparation method thereof.

Background technique

As early as the early 19th century, people discovered that temperature changes would affect the accuracy of timekeeping, and gradually realized that this phenomenon was related to the change of the elastic modulus of the hairspring in the watch with temperature. In subsequent studies, it was found that for general metals or non-transformation alloys, as the temperature increases, the elastic modulus will decrease due to the gradual weakening of the interatomic bonding force. This elastic modulus increases with the temperature. The changing relationship is extremely detrimental to the accuracy of instruments used in different temperature environments. Therefore, in order to ensure the accuracy and reliability of instruments used in different temperature environments, it is urgent to develop a material whose elastic modulus does not change or changes very little with temperature within a certain temperature range. The elastic modulus of this material The temperature coefficient is very small, and it can also be called a constant elasticity Elinvar (Elinvar) alloy.

In 1896, it was found that when the atomic percentage of Ni in Fe-Ni binary alloy is 42%, the temperature coefficient of elastic modulus can be close to zero, but its constant elastic temperature range is very narrow and its mechanical properties are poor, so it does not Get a wide range of applications. Since then, people have developed practically applicable carbide-strengthened and age-strengthened Fe-Ni-based constant elastic alloys, and formed many grades, such as: Ni-Span C, Ni-Span D and my country's 3J53, 3J58 and other constant elastic alloys alloy. Due to the poor performance consistency and low mechanical quality factor of Fe-Ni alloys, a lot of work has been done at home and abroad, and a variety of constant elastic alloys have been studied to make up for the above deficiencies of Fe-Ni alloys. One of them is ferromagnetic constant elastic alloys, which are mainly Fe-Ni and Fe-Co alloys. In order to further reduce the temperature coefficient of elastic modulus, appropriate amount of Mo, Cu, Zr, Ge and rare earth elements can be added to change the morphology of the precipitates. and quantity, so as to develop a new type of constant elastic alloy with better performance. Another widely used ferromagnetic constant elastic alloy is Co-Fe alloy, whose elastic modulus temperature coefficient is relatively stable, and the typical alloy is Elcolloy alloy. In the instrumentation industry, most elastic components are required to be free from external magnetic field interference, or not to interfere with the working magnetic field of the instrument. Therefore, ferromagnetic constant elasticity alloys cannot meet the requirements for use in magnetic fields, so it is necessary to develop Research on new non-magnetic constant elastic alloys.

Non-magnetic and constant-elastic alloys are mainly divided into two categories. The first is antiferromagnetic constant-elastic alloys, including Cr-based, Fe-Mn-based, Mn-based alloys, and the other is paramagnetic constant-elastic alloys, such as: Nb base, Ti-based and Pd-Au-based alloys, etc. Fe-Mn alloys and Mn alloys are characterized by low cost, but the constant elastic temperature zone is narrow and the corrosion resistance is poor, so they cannot meet the use environment with high precision requirements and large temperature changes. Paramagnetic Nb-based constant elasticity alloys have excellent properties and wide constant elasticity temperature range, but are difficult to process, while Pd-Au alloys are expensive and cannot be widely used. In comparison, Ti-based alloys have the advantages of non-magnetic, high corrosion resistance, high elastic limit, high fatigue limit, high tensile strength, high yield strength, good plasticity, etc. It is suitable for use in aerospace navigation instruments, instruments, etc., and has extremely high application potential. However, at present, there are few patent reports on Ti-based constant elasticity alloys with excellent comprehensive properties, and related constant elasticity materials have not been widely used. Therefore, such wide temperature range constant elasticity titanium alloys have high research and application value. .

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a non-magnetic wide temperature range constant elasticity titanium alloy with excellent comprehensive mechanical properties and a preparation method thereof, which can meet the requirements of elastic components (such as pressure sensors, strain gauge calibration beams, torsion gauges, etc.) applied in a wide temperature range. Rod gyroscopes, etc.) have special requirements for material properties in order to achieve high precision, high sensitivity, and high anti-interference ability.

In order to achieve the above object, the technical scheme of the present invention is:

A non-magnetic wide temperature range constant elasticity titanium alloy, the chemical composition of the alloy contains at least one or two or more β-stabilizing elements: Nb, Ta, Mo, V, and its content is 10-40% by weight percentage ; Can contain one or two neutral elements as needed: Zr, Sn, with a total content of 0 to 20%; can contain one or more α stable elements as needed: Al, O, with a content of 0 to 20% 5%; the balance is Ti.

The non-magnetic wide temperature range constant elasticity titanium alloy has a constant elastic modulus in a wide temperature range of -150-350°C.

In the non-magnetic wide temperature range constant elasticity titanium alloy, the temperature coefficient of elastic modulus of the alloy is less than 20×10 ^-6 /°C in a wide temperature range of -150 to 350°C.

In the non-magnetic wide temperature range constant elasticity titanium alloy, the temperature coefficient of elastic modulus of the alloy is less than 0.5×10 ^-6 /°C in the temperature range of -50 to 50°C.

In the non-magnetic wide temperature range constant elasticity titanium alloy, the elastic modulus of the alloy is 60-90 GPa, and the yield strength is greater than 600 MPa.

For the preparation method of the non-magnetic wide temperature constant elastic titanium alloy, the volume fraction and lattice parameters of the orthogonal structure α" phase of the alloy are regulated by heat treatment, the heat treatment temperature is 250-550 DEG C, and the heat treatment time is 0.5-48 hours .

The design idea of the present invention is:

Traditional ferromagnetic galvanostatic alloys rely on magnetic-related mechanisms. For example, the modulus hardening caused by magnetostriction cancels the modulus softening caused by atomic thermal shock, resulting in macroscopic galvanostatic properties of the alloy. Other non-magnetic constant-elastic alloys can control the elastic properties through antiferromagnetic-paramagnetic transition, phase transformation, and cold working to introduce texture. These methods are relatively complicated and interfere with external magnetic fields. For β-titanium alloys, heat treatment can introduce a large number of nanoscale metastable transition phases, which can significantly adjust the elastic properties of the alloy. When adjusted by a suitable heat treatment regime, the alloy can exhibit constant elastic properties within a certain temperature range.

The wide temperature range constant elasticity titanium alloy and the preparation method thereof provided by the present invention have the advantages and beneficial effects as follows:

1. The wide temperature range constant elasticity titanium alloy provided by the present invention has the advantages of high strength, wide temperature range, good plasticity and constant elasticity. The details are as follows: the yield strength of the alloy is greater than 600MPa, and the constant modulus temperature range is -150 ～350℃, the elongation is 8～20%, the temperature coefficient of elastic modulus is less than 20×10 ^-6 /℃, and it has excellent comprehensive performance. In addition, the material is non-magnetic, so that its function is not disturbed by external magnetic fields, and the working magnetic field in the actual working environment is not affected by the existence of the material, which significantly improves the magnetic field stability and anti-interference characteristics.

2. The present invention creatively proposes a method for preparing a wide-temperature constant-modulus titanium alloy. Compared with traditional constant-modulus materials, the properties of the alloy do not depend on adjusting the original composition. This method only adjusts the aging temperature and aging time. The desired relationship between modulus and temperature can be obtained without changing the original composition of the material from the source, so it brings great convenience to production and use, and has good product consistency and unprecedented technical effects. Its application has huge economy.

3. The preparation method of titanium alloy with wide temperature range and constant modulus adopted in the present invention is suitable for a series of β titanium alloys capable of precipitation of orthogonal structure precipitation phase through aging. Therefore, the preparation method is not limited to the original composition of titanium alloy, and can be based on the original composition of titanium alloy. It is necessary to change the heat treatment process to achieve constant modulus properties for β-titanium alloys with different compositions.

Description of drawings

Figure 1 shows the room temperature tensile curve of Ti-Nb-Zr-Sn-O alloy.

Figure 2 shows the room temperature tensile curve of the Ti-Nb-Al alloy.

FIG. 3 is a graph showing the relationship between the modulus of Ti-Nb-Zr-Sn-O alloy and the temperature.

FIG. 4 is a graph showing the relationship between the modulus of Ti-Nb-Al alloy and temperature.

Figure 5 shows the XRD diffraction patterns of the Ti-Nb-Zr-Sn-O alloy hot-rolled and aged at 450°C for 4 hours. (a) original state, (b) heat-treated state.

Figure 6 shows the microstructure of the Ti-Nb-Zr-Sn-O alloy in the hot-rolled state and after aging at 450°C for 4 hours.

Detailed ways

In the specific implementation process, the preparation method of the non-magnetic wide temperature range constant elasticity titanium alloy of the present invention includes the following preparation steps: electrode manufacturing→melting→blanking→hot rolling→aging heat treatment→air cooling. The scope of application of the non-magnetic wide temperature range constant elasticity titanium alloy is: it contains at least one or two or more β-stabilizing elements (10% to 40% by weight), and can contain one or more than two neutral elements ( 0 to 20% by weight), a beta titanium alloy that may contain one or more than two α-stabilizing elements (0 to 5% by weight). Wherein, the aging heat treatment temperature is 250-550 degrees Celsius, and the holding time is 0.5-48 hours; preferably, the aging heat treatment temperature is 300-500 degrees Celsius, and the holding time is 1-24 hours.

Below, in conjunction with the accompanying drawings and specific embodiments, the present invention will be described in further detail:

Example 1

In this embodiment, the constant modulus Ti-Nb-Zr-Sn-O alloy in a wide temperature range and its preparation process are as follows:

In terms of weight percentage, the composition of the constant modulus Ti-Nb-Zr-Sn-O alloy in a wide temperature range includes: Nb24%, Zr4%, Sn8%, O0.1%, and Ti balance.

The preparation method of the constant modulus Ti-Nb-Zr-Sn-O alloy in a wide temperature range is as follows: according to the proportion of the required components, the raw materials are smelted in a secondary vacuum consumable electric arc furnace according to the conventional method, and then forged through billeting. , and hot-rolled titanium alloy processing technology to obtain a titanium alloy round bar with a diameter of 12 mm. After aging treatment at 450°C for 4 hours, air-cooled to room temperature.

As shown in Figure 1, it can be seen from the tensile curve of the titanium alloy at room temperature in this example that the yield strength of the alloy is higher than 1000 MPa, and can reach 1200 MPa under proper heat treatment conditions, which is superior to other traditional constant elasticity alloys .

The wide temperature range constant modulus titanium alloy prepared in this example has an elastic modulus of 78GPa, which remains unchanged in the range of -170°C to 350°C (Fig. 3), and its elastic modulus temperature coefficient e is 1.5× 10 ^-6 /°C. Furthermore, it has an orthogonal structure precipitation phase distributed in the β-phase matrix (FIG. 5), and its size is 20-80 nm (FIG. 6).

Example 2

In this embodiment, the constant modulus Ti-Nb-Al alloy in a wide temperature range and its preparation process are as follows:

In terms of weight percentage, the composition of the constant modulus Ti-Nb-Al alloy in a wide temperature range includes: Nb25%, Al5%, and Ti balance.

The preparation method of the constant modulus Ti-Nb-Al alloy in a wide temperature range is as follows: according to the required composition ratio, the raw materials are smelted in a secondary vacuum consumable electric arc furnace according to the conventional method, and then the raw materials are forged by billet and hot rolled. Titanium alloy processing technology to obtain a titanium alloy round rod with a diameter of 12 mm. After aging treatment at 400°C for 2 hours, air-cooled to room temperature.

As shown in Figure 2, it can be seen from the tensile curve of the titanium alloy at room temperature in this example that the yield strength of the alloy is higher than 1000 MPa, and it has better mechanical properties.

The wide temperature range constant modulus titanium alloy prepared in this example has an elastic modulus of 63GPa, which remains unchanged in the range of 200°C to 500°C (Fig. 4), and its elastic modulus temperature coefficient e is 9.1×10 ^-6 /°C.

The elastic properties of other titanium alloy components prepared by this scheme are listed in Table 1.

Table 1 Alloy composition elastic properties

In Example 3 to Example 5, the preparation method of the non-magnetic wide temperature range constant elasticity titanium alloy is basically the same as that in Example 1, the difference is: in Example 3, after aging treatment at 300 ° C for 24 hours, air-cooled to room temperature . In Example 4, after aging treatment at 350°C for 12 hours, it was air-cooled to room temperature. In Example 5, after aging treatment at 500°C for 1 hour, it was air-cooled to room temperature.

The results of the examples show that the titanium alloy prepared by the method of the present invention has a nearly constant elastic modulus and excellent mechanical properties in a wide temperature range of -150 to 350°C. The temperature coefficient of elastic modulus of the constant elastic titanium alloy prepared by this method is less than 20×10 ^-6 /℃ in a wide temperature range, and the temperature coefficient of elastic modulus of the constant elastic titanium alloy without magnetic wide temperature range can be -50 The temperature range of ~50°C is less than 0.5×10 ^-6 /°C. At the same time, the room temperature properties of the non-magnetic wide temperature constant elastic titanium alloy are: the elastic modulus is 60-90GPa, the yield strength is higher than 600MPa, the elongation is 8-20%, and it has excellent comprehensive mechanical properties. The equal-modulus titanium alloy in the present invention is a non-magnetic material, which is not disturbed by the magnetic field of the actual use environment, and can achieve constant elastic performance in a very wide temperature range, and the temperature coefficient of elastic modulus can be adjusted, so it has a good application prospects.

Claims (6)

1. A non-magnetic wide-temperature-range constant-elasticity titanium alloy is characterized in that the chemical composition of the alloy at least contains one or more than two beta stable elements in percentage by weight: 10-40% of Nb, Ta, Mo and V; it may contain one or two neutral elements as required: zr and Sn, the total content is 0-20%; one or two or more α stabilizing elements may be contained as required: 0-5% of Al and O; the balance being Ti.

2. The non-magnetic wide temperature range constant-elasticity titanium alloy according to claim 1, wherein the alloy has a constant elastic modulus in a wide temperature range of-150 to 350 ℃.

3. The nonmagnetic wide temperature range constant elasticity titanium alloy according to claim 1, wherein the temperature coefficient of elastic modulus of the alloy is less than 20 x 10 in a wide temperature range of-150 to 350 ℃^-6/℃。

4. The nonmagnetic wide temperature range constant elasticity titanium alloy according to claim 1, wherein the temperature coefficient of elastic modulus of the alloy is less than 0.5 x 10 in the temperature range of-50 to 50 ℃^-6/℃。

5. The non-magnetic wide-temperature-range constant-elasticity titanium alloy according to claim 1, wherein the elastic modulus of the alloy is 60-90 GPa, and the yield strength is more than 600 MPa.

6. A method for preparing a nonmagnetic wide temperature range constant elasticity titanium alloy as defined in any one of claims 1 to 5, wherein the volume fraction of the α "phase of the alloy orthorhombic structure and the lattice parameter are controlled by heat treatment at a temperature of 250 to 550 ℃ for 0.5 to 48 hours.

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