阅读说明：本技术 一种负热膨胀系数可调的钛铌合金的制备方法 (Preparation method of titanium-niobium alloy with adjustable negative thermal expansion coefficient ) 是由 陈锋 武祥为 邹雯倩 于 2020-11-27 设计创作，主要内容包括：本发明公开了一种负热膨胀系数可调的钛铌合金的制备方法,所述制备方法为：将掺杂有Nb元素的钛合金经固溶处理后进行淬火冷却,得到由β+α″相组成的钛铌合金,再将其进行冷形变加工,冷形变加工后进行预时效处理,得到随温度变化时沿轧制方向伸缩的钛铌合金。本发明制备方法通过改变预时效处理时间,使合金沿轧制方向在25℃～300℃的温度范围内具有-33.0×10～(-6)/K～-0.9×10～(-6)/K的可调节负热膨胀系数；本发明制得的钛铌合金能够适用于制备热开关、智能阀门等高性能的温度敏感元件以及高尺寸稳定性要求的高精度仪器构件。(The invention discloses a preparation method of a titanium-niobium alloy with adjustable negative thermal expansion coefficient, which comprises the following steps: and (2) carrying out solution treatment on the titanium alloy doped with the Nb element, quenching and cooling to obtain a titanium-niobium alloy consisting of a beta + alpha' phase, carrying out cold deformation processing on the titanium-niobium alloy, and carrying out pre-aging treatment after the cold deformation processing to obtain the titanium-niobium alloy which stretches along the rolling direction along with the temperature change. The preparation method of the invention changes the pre-aging treatment time to ensure that the alloy has a temperature of-33.0 multiplied by 10 in the rolling direction within the temperature range of 25 ℃ to 300 DEG C ‑6 /K～‑0.9×10 ‑6 of/KThe negative thermal expansion coefficient can be adjusted; the titanium-niobium alloy prepared by the invention can be suitable for preparing high-performance temperature sensitive elements such as thermal switches, intelligent valves and the like and high-precision instrument components with high dimensional stability requirements.)

1. A preparation method of a negative thermal expansion coefficient adjustable titanium-niobium alloy is characterized by comprising the following steps: and (2) carrying out solution treatment on the titanium alloy doped with the Nb element, quenching and cooling to obtain a titanium-niobium alloy consisting of a beta + alpha' phase, carrying out cold deformation processing on the titanium-niobium alloy, and carrying out pre-aging treatment after the cold deformation processing to obtain the titanium-niobium alloy which stretches along the rolling direction along with the temperature change.

2. The method for preparing the negative thermal expansion coefficient adjustable titanium-niobium alloy as claimed in claim 1, wherein: in the titanium alloy doped with the Nb element, the weight percentages of the elements are as follows: nb: 34.0% -34.1%; o: 0.10 to 0.12 percent; the balance being Ti.

3. The method for preparing the negative thermal expansion coefficient adjustable titanium-niobium alloy as claimed in claim 1, wherein: the treatment temperature of the pre-aging treatment is 300-304 ℃, and the treatment time is 0-150 min.

4. The method for preparing the negative thermal expansion coefficient adjustable titanium-niobium alloy as claimed in claim 1, wherein: in the cold deformation processing process, the deformation amount of the titanium-niobium alloy is 92-95%.

5. The method for preparing the negative thermal expansion coefficient adjustable titanium-niobium alloy as claimed in claim 1, wherein: the temperature of the solution treatment is 800-950 ℃, and the time of the solution treatment is 30-60 min.

6. The method for preparing the negative thermal expansion coefficient adjustable titanium-niobium alloy as claimed in claim 1, wherein: the quenching medium during quenching and cooling is water.

7. The method for preparing the negative thermal expansion coefficient adjustable titanium-niobium alloy as claimed in claim 1, wherein the method specifically comprises the following steps:

(1) according to the titanium alloy composition, Ti, Nb and TiO₂Preparing alloy for raw materials;

(2) repeatedly smelting the prepared raw materials in a magnetically-stirred vacuum non-consumable arc furnace to obtain an ingot with uniform components;

(3) hot forging the cast ingot into a bar, carrying out solution treatment on the alloy bar at 800-950 ℃ for 30-60 min, and then putting the alloy bar into water for quenching and cooling to obtain the titanium-niobium alloy with beta + alpha' phase;

(4) turning to remove oxide skin on the surface of the bar, and then performing cold deformation processing with the deformation amount of 92-95% at room temperature;

(5) and (3) performing pre-aging treatment on the alloy in the step (4) at the temperature of 300-304 ℃ for 0-150 min.

8. The method for preparing the negative thermal expansion coefficient adjustable titanium-niobium alloy as claimed in claim 7, wherein: in the step (3), the hot forging temperature is 900-1000 ℃, the deformation is 70-80%, and the hot forging is carried out in the air.

Technical Field

The invention relates to a preparation method of a titanium-niobium alloy with adjustable negative thermal expansion coefficient.

Background

The phenomenon in which the volume or length of an object changes relatively with changes in temperature is called thermal expansion. Common materials generally all have a positive coefficient of thermal expansion, which is its intrinsic nature. When the object has large temperature change, on one hand, thermal stress is easily generated, for example, the difference of the thermal expansion coefficients between the substrate and the film generates internal stress, thereby influencing the physical, electrical and thermal properties of the film; on the other hand, the member has obvious dimensional change, thereby affecting the precision of precision instruments, and causing the expansion joint to be reserved at the joint of large-scale structures such as bridges, railway tracks and the like. When the positive thermal expansion material is compounded with a proper negative thermal expansion material, the expansion coefficient of the materials can be adjusted in a wide range, the connection of dissimilar materials is realized, and even zero expansion is realized, so that the problems can be well solved. When the negative thermal expansion coefficient of the material is extremely small or close to zero, the material can be directly used for preparing high-precision instrument components with high dimensional stability requirements. On the other hand, when the positive thermal expansion material and the material with high negative thermal expansion characteristic are compounded, the material can also be used for preparing high-performance temperature sensitive elements such as a thermal switch, an intelligent valve and the like.

The developed relatively mature negative thermal expansion materials are mainly ceramic materials, such as oxide ceramics (tungstate, molybdate, chromate, etc.), microcrystalline glass, etc., but the manufacturing process is complex, the cost is high, and the mechanical strength is low. From the practical perspective, the metal material has the advantages of high strength, good toughness, easy processing and the like, so the development of the metal material with negative thermal expansion has important practical value.

Several titanium alloys with negative thermal expansion characteristics have been reported in recent years. H, Y, Kim, etc. adopts Ti-35Nb-3Zr-2Ta-0.3O alloy, and obtains-0.8 x 10 at the temperature of-93-17 ℃ by processing means of solution quenching, 98.5% deformation rate cold rolling, etc^-6A negative expansion coefficient of/K (H.Y.Kim, L.Wei, S.Kobayashi. Nanodomain structure and its effect on abnormal thermal expansion of Ti-23Nb-2Zr-0.7Ta-1.2O alloy. acta. Mater.61(2013) 4874. sup. 4886). Y, L, Hao, etc. adopts Ti-24Nb-4Zr-8Sn alloy, and is obtained through hot forging, hot rolling with 95% deformation rate and other processing means at the temperature of 20-300 deg.cTo obtain-7X 10^-6Negative Expansion coefficient of/K (Y.L.Hao, H.L.Wang, T.Li.Superelasticity and tubular Thermal Expansion across a Wide Temperature range. J.Mater.Sci.Technol.32(2016) 705-.

Disclosure of Invention

The purpose of the invention is as follows: the invention provides a preparation method of a titanium niobium alloy with adjustable negative thermal expansion coefficient, aiming at the problems of narrow adjustable range of negative thermal expansion coefficient and narrow applicable temperature range of titanium alloy with negative thermal expansion characteristic in the prior art.

The technical scheme is as follows: the invention relates to a preparation method of a titanium-niobium alloy with adjustable negative thermal expansion coefficient, which comprises the following steps: and carrying out solution treatment on the titanium alloy doped with the Nb element, quenching and cooling to obtain the titanium-niobium alloy simultaneously having a beta + alpha' phase, carrying out cold deformation processing on the titanium-niobium alloy, and carrying out pre-aging treatment after the cold deformation processing to obtain the titanium-niobium alloy which stretches along the rolling direction along with the temperature change.

The titanium alloy doped with the Nb element comprises the following elements in percentage by weight: nb: 34.0% -34.1%; o: 0.10 to 0.12 percent; the balance being Ti.

Wherein the treatment temperature of the pre-aging treatment is 300-304 ℃, and the treatment time is 0-150 min.

Wherein, in the cold deformation processing process, the deformation amount of the titanium-niobium alloy is 92-95%.

Wherein the temperature of the solid solution treatment is 800-950 ℃, and the time of the solid solution treatment is 30-60 min.

Wherein the quenching medium during quenching and cooling is water.

The preparation method specifically comprises the following steps:

(1) according to the titanium alloy composition, Ti, Nb and TiO₂As raw materialsPreparing an alloy;

(2) repeatedly smelting the prepared raw materials in a magnetically-stirred vacuum non-consumable arc furnace to obtain an ingot with uniform components;

(3) hot forging the cast ingot into a bar, carrying out solution treatment on the alloy bar at 800-950 ℃ for 30-60 min, and then putting the alloy bar into water for quenching and cooling to obtain the titanium-niobium alloy with beta + alpha' phase;

(4) turning to remove oxide skin on the surface of the bar, and then performing cold deformation processing with the deformation amount of 92-95% at room temperature;

(5) and (3) performing pre-aging treatment on the alloy in the step (4) at the temperature of 300-304 ℃ for 0-150 min.

Wherein, in the step (3), the hot forging temperature is 900-1000 ℃, the deformation is 70-80%, and the hot forging is carried out in the air.

The mechanism of the preparation method of the invention for preparing the titanium-niobium alloy with the large-range adjustable negative thermal expansion coefficient is as follows: firstly, the alloy component of the invention is Ti- (34.0 wt% -34.1 wt%) Nb- (0.10 wt% -0.12 wt%) O, and the titanium alloy doped with Nb element can be subjected to solution treatment and quenching cooling to obtain the titanium-niobium alloy consisting of beta + alpha phase; then, through 92% -95% cold deformation, the production of < 110 > parallel to the rolling direction_βAnd < 010 >_α″Strong texture, and < 110 >_β//＜010＞_α″In the cold rolling process, the rolling with large deformation rate of more than 92 percent can form strong texture in the rolling direction, thereby increasing the negative thermal expansion coefficient in the rolling direction (the larger the deformation amount is, the larger the negative thermal expansion coefficient in the rolling direction is, for example, for CR-Ti-34Nb alloy, when the deformation rate is 92 percent, the average expansion coefficient alpha in the range of 25-300 DEG C_25℃-300℃＝-33.0×10^-6K; when the deformation rates are 90%, 60% and 30%, respectively, the average expansion coefficient alpha is_25℃-300℃Are respectively-30.1X 10^-6/K、-22.5×10^-6/K、-9.6×10^-6K) is added. In the alloy temperature rising stage, alpha' → beta ((beta))From the XRD pattern of FIG. 1, CR-Ti-34Nb alloy can be calculated according to the Bragg equationLattice constant of each phase: b_α″＝0.482) The length in the rolling direction is continuously reduced; in the alloy cooling stage, the length of the rolling direction is continuously increased from beta → alpha', so that the alloy has a negative thermal expansion coefficient; when the alloy after cold rolling is subjected to pre-aging treatment at 300-304 ℃, the alpha 'phase content in the alloy is gradually reduced along with the prolonging of the treatment time, because the alpha' phase is unstable, the alpha 'phase is transformed into the alpha 0 phase more along with the prolonging of the high-temperature treatment time, and therefore the alpha' phase content in the alloy is lower (when the alloy matrix consists of beta and alpha 'phases, the alpha' phase is continuously reduced and gradually transformed into the beta phase along with the prolonging of the pre-aging treatment time), thereby ensuring that the alloy has an adjustable negative thermal expansion coefficient (-33.0 alpha 110) within a wider temperature range of 25-300 DEG C^-6/K～-0.9×10^-6K); when the pre-aging treatment time is between 150min and 240min, the expansion coefficient alpha is_25℃-300℃Can be adjusted to zero. Meanwhile, the content of O added into the alloy can improve the applicable temperature range of the titanium alloy and can also effectively improve the strength of the alloy.

Has the advantages that: the preparation method of the invention changes the pre-aging treatment time to ensure that the alloy has a temperature of-33.0 multiplied by 10 in the rolling direction within the temperature range of 25 ℃ to 300 DEG C^-6/K～-0.9×10^-6An adjustable negative thermal expansion coefficient of/K; therefore, the prepared titanium-niobium alloy has a large adjustable range of negative thermal expansion coefficient, wide applicable temperature range and stable shape memory effect during temperature cycle; the method can be suitable for preparing high-performance temperature sensitive elements such as thermal switches, intelligent valves and the like and high-precision instrument components with high dimensional stability requirements.

Drawings

FIG. 1 is an XRD spectrum of a titanium-niobium alloy prepared in examples 1 to 7 of the present invention;

FIG. 2 is a graph showing a peak height ratio I according to diffraction intensity in FIG. 1_α″(020)/I_β(110)The volume fraction of the alpha' phase obtained;

FIG. 3 is the rolling strain variation curve with temperature rise after pre-aging treatment at 300-304 deg.C for different time;

FIG. 4 is a graph showing the variation of the rolling thermal strain of the Ti-Nb alloy obtained in example 1 during thermal cycling;

FIG. 5 is a graph showing the variation of the rolling thermal strain of the Ti-Nb alloy obtained in example 6 during thermal cycling.

Detailed Description

The technical solution of the present invention is further described with reference to the following specific embodiments.

Ti, Nb and TiO used in examples of the present invention₂The purity of the raw materials is more than 99.9 wt%.

Example 1

The preparation method of the titanium-niobium alloy comprises the following steps: (1) with Ti, Nb and TiO₂Preparing alloy by taking the powder as a raw material, and weighing the following substances by weight: ti: 65.725 g; nb: 34.000 g; TiO 2₂: 0.275 g; the weight percentages of the elements of the prepared alloy are as follows: nb: 34.0 percent; o: 0.11 percent, and the balance being Ti; repeatedly smelting the prepared raw materials in a magnetically-stirred vacuum non-consumable electric arc furnace for five times to obtain an ingot with uniform components; (2) hot forging the cast ingot into a bar at 900 ℃, wherein the deformation amount is 80%; (3) carrying out solution treatment on the bar material in the step (2) at 800 ℃ for 60min, and then putting the bar material into water for quenching and cooling; (4) turning to remove oxide skin on the surface of the bar, and then performing cold rolling deformation with the deformation of 92% at room temperature. After the treatment, the alloy with the phase composition of beta matrix and a small amount of alpha' phase is obtained; the volume fraction of the alpha "phase in the alloy was calculated to be 0.337. The average expansion coefficient alpha of the alloy in the rolling direction is in the range of 25-300 DEG C_25℃-300℃＝-33.0×10^-6and/K. As can be seen from fig. 4, the alloy has a stable shape memory effect during temperature cycling and has negative thermal expansion characteristics.

Example 2

The preparation method of the titanium-niobium alloy comprises the following steps: (1) with Ti, Nb and TiO₂Preparing alloy by taking the powder as a raw material, and weighing the following substances by weight: ti: 65.600 g; nb: 34.100 g; TiO 2₂: 0.300 g; the weight percentages of the elements of the prepared alloy are as follows: nb: 34.1 percent; o: 0.12 percent, and the balance being Ti; will be provided withRepeatedly smelting the prepared raw materials in a magnetically-stirred vacuum non-consumable electric arc furnace for five times to obtain an ingot with uniform components; (2) hot forging the cast ingot into a bar at 950 ℃, wherein the deformation amount is 70%; (3) carrying out solution treatment on the bar material in the step (2) at 850 ℃ for 30min, and then putting the bar material into water for quenching and cooling; (4) turning to remove oxide skin on the surface of the bar, and then performing cold rolling deformation with the deformation of 95% at room temperature; (5) and (4) performing pre-aging treatment on the cold-rolled bar in the step (4) at 302 ℃ for 3 min. After the treatment, the alloy with the phase composition of beta matrix and a small amount of alpha' phase is obtained; the volume fraction of the alpha "phase in the alloy was calculated to be 0.247. The average expansion coefficient alpha of the alloy in the rolling direction is in the range of 25-300 DEG C_25℃-300℃＝-19.0×10^-6and/K. The alloy has stable shape memory effect and negative thermal expansion characteristic during temperature cycle.

Example 3

The preparation method of the titanium-niobium alloy comprises the following steps: (1) with Ti, Nb and TiO₂Preparing alloy by taking the powder as a raw material, and weighing the following substances by weight: ti: 65.650 g; nb: 34.100 g; TiO 2₂: 0.250 g; the weight percentages of the elements of the prepared alloy are as follows: nb: 34.1 percent; o: 0.10 percent, and the balance being Ti; repeatedly smelting the prepared raw materials in a magnetically-stirred vacuum non-consumable electric arc furnace for five times to obtain an ingot with uniform components; (2) hot forging the cast ingot into a bar at 1000 ℃ with the deformation amount of 75 percent; (3) carrying out solution treatment on the bar material in the step (2) at 950 ℃ for 45min, and then putting the bar material into water for quenching and cooling; (4) turning to remove oxide skin on the surface of the bar, and then performing cold rolling deformation with the deformation of 93% at room temperature; (5) and (4) performing pre-aging treatment on the cold-rolled bar in the step (4) at 304 ℃ for 10 min. After the treatment, the alloy with the phase composition of beta matrix and a small amount of alpha' phase is obtained; the volume fraction of the alpha "phase in the alloy was calculated to be 0.169. The average expansion coefficient alpha of the alloy in the rolling direction is in the range of 25-300 DEG C_25℃-300℃＝-6.3×10^-6and/K. The alloy has stable shape memory effect and negative thermal expansion characteristic during temperature cycle.

Example 4

The preparation method of the titanium-niobium alloy comprises the following steps: (1) with Ti, Nb and TiO₂Preparing alloy by taking the powder as a raw material, and weighing the following substances by weight: ti: 65.725 g; nb: 34.000 g; TiO 2₂: 0.275 g; the weight percentages of the elements of the prepared alloy are as follows: nb: 34.0 percent; o: 0.11 percent, and the balance being Ti; repeatedly smelting the prepared raw materials in a magnetically-stirred vacuum non-consumable electric arc furnace for five times to obtain an ingot with uniform components; (2) hot forging the cast ingot into a bar at 950 ℃, wherein the deformation amount is 80%; (3) carrying out solution treatment on the bar material in the step (2) at 800 ℃ for 30min, and then putting the bar material into water for quenching and cooling; (4) turning to remove oxide skin on the surface of the bar, and then performing cold rolling deformation with the deformation of 92% at room temperature; (5) and (4) performing pre-aging treatment on the cold-rolled bar in the step (4) at 300 ℃ for 30 min. After the treatment, the alloy with the phase composition of beta matrix and a small amount of alpha' phase is obtained; the volume fraction of the alpha "phase in the alloy was calculated to be 0.152. The average expansion coefficient alpha of the alloy in the rolling direction is in the range of 25-300 DEG C_25℃-300℃＝-3.3×10^-6and/K. The alloy has stable shape memory effect and negative thermal expansion characteristic during temperature cycle.

Example 5

The pre-ageing time for the cold rolled bar of example 2 was increased to 120min, and the rest of the process was exactly the same as in example 2. After the treatment, the alloy phase composition becomes a beta matrix plus a small amount of alpha' phase; the volume fraction of the alpha "phase was calculated to be 0.144. The average expansion coefficient alpha of the alloy along the rolling direction in the range of 25-300 DEG C_25℃-300℃＝-1.5×10^-6and/K, and the alloy has a shape memory effect and negative thermal expansion characteristics when subjected to temperature cycling.

Example 6

The pre-ageing time for the cold rolled bar of example 3 was increased to 150min, and the rest of the process was exactly the same as in example 3. After the treatment, the alloy phase composition becomes a beta matrix plus a small amount of alpha' phase; the volume fraction of the alpha "phase was calculated to be 0.141. The average expansion coefficient alpha of the alloy along the rolling direction in the range of 25-300 DEG C_25℃-300℃＝-0.9×10^-6and/K. As can be seen from fig. 5, the alloy has a stable shape memory effect during temperature cycling and has negative thermal expansion characteristics.

Example 7

The pre-ageing time for the cold rolled bar of example 4 was increased to 240min, and the rest of the process was exactly the same as in example 4. After the treatment, the alloy phase composition becomes a beta matrix plus a small amount of alpha' phase; the volume fraction of the alpha "phase was calculated to be 0.138. The average expansion coefficient alpha of the alloy along the rolling direction in the range of 25-300 DEG C_25℃-300℃＝0.4×10^-6and/K, and the alloy has a shape memory effect during temperature cycling and has positive thermal expansion characteristics.

As can be seen from FIGS. 1-2, the alloy after cold rolling (CR state) consists of a beta + alpha' phase. As the pre-aging treatment time is prolonged, the peak height of the alpha 'phase is gradually reduced, and the volume content of the alpha' phase is gradually reduced. As can be seen from FIG. 3, the average thermal expansion coefficient alpha of the alloy between 25 ℃ and 300 ℃ increases with the pre-aging treatment time_25℃-300℃from-33.0X 10^-6the/K (not aged) gradually changes to-0.9X 10^-6The expansion coefficient of the steel plate can be adjusted to be zero when the pre-aging treatment time is between 150min and 240 min.

The method of the invention first obtains an alloy consisting of a beta + alpha phase, then obtains < 110 > parallel to the rolling direction by cold rolling with large deformation_βAnd < 010 >_α″Strong texture, finally, the transformation from the alpha 'phase to the beta phase is realized by adding a pre-aging treatment step, and the volume fraction of the alpha' phase in the alloy is adjusted by adjusting the pre-aging treatment time, thereby realizing the adjustment of the negative thermal expansion coefficient of the alloy along the rolling direction. When the preaging time is changed within the range of 0 min-150 min, the volume fraction (ratio) of alpha' phase in the alloy can be changed within a large range, so that the alloy has-33.0 multiplied by 10 within the temperature range of 25 ℃ to 300 ℃ along the rolling direction^-6/K～-0.9×10^-6the/K can be adjusted to negative thermal expansion coefficient.