Alpha-type high-specific-modulus heat-resistant easy-to-mold titanium alloy and preparation method thereof

文档序号：128754 发布日期：2021-10-22 浏览：16次中文

阅读说明：本技术 一种α型高比模量耐热易成型钛合金及制备方法 (Alpha-type high-specific-modulus heat-resistant easy-to-mold titanium alloy and preparation method thereof ) 是由杨治军李景娴李中琴苏捷侯树森于 2021-07-19 设计创作，主要内容包括：本发明属于航空航天用钛合金材料领域,公开了一种α型高比模量耐热易成型钛合金,以质量百分含量表示,钛合金由以下成分组成：Al 12.0％～14.0％,Zr 3.5％～6.0％,Sn 3.0％～6.0％,B 0.5％～1.0％,稀土元素Gd 0.05％～0.1％,O 0.10%～0.25%,余量为Ti及不可避免的杂质元素。本发明钛合金具有高模量、低密度、良好塑韧性和耐热性能,突破了钛合金弹性模量与塑韧性匹配的关键技术,在保证塑韧性的同时具有较高的弹性模量,同时具备低密度和耐高温等优异的性能,在航空航天、舰船装备及兵器工业等领域具有良好的技术应用与市场前景。(The invention belongs to the field of titanium alloy materials for aerospace, and discloses an alpha-type titanium alloy with high specific modulus, heat resistance and easy forming, which comprises the following components in percentage by mass: 12.0 to 14.0 percent of Al, 3.5 to 6.0 percent of Zr, 3.0 to 6.0 percent of Sn, 0.5 to 1.0 percent of B, 0.05 to 0.1 percent of rare earth element Gd, 0.10 to 0.25 percent of O, and the balance of Ti and inevitable impurity elements. The titanium alloy has high modulus, low density, good ductility and toughness and heat resistance, breaks through the key technology of matching the elasticity modulus and the ductility and toughness of the titanium alloy, has higher elasticity modulus while ensuring the ductility and toughness, has excellent performances of low density, high temperature resistance and the like, and has good technical application and market prospect in the fields of aerospace, ship equipment, weapon industry and the like.)

1. The alpha-type titanium alloy with high specific modulus, heat resistance and easy forming is characterized by comprising the following components in percentage by mass: 12.0 to 14.0 percent of Al, 3.5 to 6.0 percent of Zr, 3.0 to 6.0 percent of Sn, 0.5 to 1.0 percent of B, 0.05 to 0.1 percent of rare earth element, 0.10 to 0.25 percent of O, and the balance of Ti and inevitable impurity elements.

2. The α -type high specific modulus heat resistant easily formable titanium alloy according to claim 1, wherein said rare earth element is Gd.

3. The α -type high specific modulus heat resistant easily formable titanium alloy according to claim 1 or 2, wherein the titanium alloy has an aluminum equivalent [ Al [ ] in the titanium alloy]_{When in use}13.7 to 16.0, wherein [ Al]_{When in use}And the formula is defined as the mass percent of each element in the titanium alloy, wherein, =% Al +% Sn/3+% Zr/6.

4. The α -type high specific modulus heat resistant easily formable titanium alloy according to claim 3, wherein the titanium alloy has molybdenum equivalent [ Mo ]]_{When in use}Is 0.

5. The alpha-type titanium alloy with high specific modulus, heat resistance and easy molding as claimed in claim 1, wherein the impurity element is C, N, H, and the mass percentage of the impurity element in the titanium alloy is as follows: c is less than or equal to 0.10 percent, N is less than or equal to 0.05 percent, and H is less than or equal to 0.01 percent.

6. A preparation method of the alpha-type titanium alloy with high specific modulus, heat resistance and easy forming as claimed in any one of claims 1 to 5 is characterized by comprising the following steps:

(1) smelting and ingot casting: the titanium alloy composition of any one of claims 1 to 5 is proportioned, and the prepared titanium alloy raw material is smelted and cast to obtain an alloy cast ingot;

(2) forging: cogging the alloy ingot prepared in the step (1) at 1100-1280 ℃, and forging at least once at 1020 +/-10 ℃, wherein the finish forging temperature is not lower than 860 ℃; then forging or rolling the alloy into a required forge piece or plate at 980 +/-10 ℃, wherein the finish forging temperature is not lower than 850 ℃.

7. The preparation method according to claim 6, wherein the smelting is carried out by adopting a vacuum consumable arc smelting technology to smelt the titanium alloy raw material.

Technical Field

The invention relates to the field of titanium alloy materials for aerospace, in particular to an alpha-type titanium alloy with high specific modulus, heat resistance and easiness in forming and a preparation method thereof.

Background

The titanium and the titanium alloy have excellent performances of high specific strength, good plasticity and toughness, corrosion resistance, weldability and the like, and have outstanding weight reduction effect when being used as aerospace materials. However, the modulus of titanium alloys is only about 105GPa, half the elastic modulus of steel. Therefore, an increase in wall thickness or a reinforcement structure is required in the design, which results in an increase in weight, impairing the weight reduction advantage of the titanium alloy over other materials. The working temperature of pressure-resistant components such as hypersonic missile rudder wings, skins and rudder frameworks is as high as 600 ℃, and the requirement for weight reduction is urgent. Therefore, higher demands are made on the specific modulus, heat resistance and ductility of titanium alloys.

The elastic modulus is essentially a physical quantity representing the binding force between atoms, and it depends mainly on the properties of the metal, and is closely related to the crystal type and the atomic distance. The modulus of elasticity is a structurally insensitive parameter, determined primarily by the composition of the material. The elastic modulus of the alloy changes significantly only when a second phase with significantly different properties is included in the alloy.

At present, elements such as Al, B and C are mainly added at home and abroad to respectively form second phases such as TiAl, TiB and TiC and the like so as to improve the elastic modulus of the titanium alloy. However, the presence of the second phase tends to lower the ductility and toughness of the titanium alloy, and the cold-hot workability is poor. Therefore, under the condition of ensuring the ductility and toughness, the improvement of the elastic modulus of the titanium alloy is a technical problem.

In addition, most of the existing high-elasticity-modulus titanium alloys are alpha + beta type or beta type alloys, the elasticity moduli of pure alpha-Ti and pure beta-Ti are respectively 114 GPa and 73GPa, the contribution of the elasticity modulus of alpha phase is 40 percent higher than that of beta phase, and the alloys contain a large amount of beta phase and have lower elasticity modulus. Meanwhile, beta-stabilizing elements such as Mo, Ni, V, Nb, Co, Fe and the like are required to be added into the alloy, and the elements have high density and low specific modulus and are not beneficial to weight reduction. Meanwhile, the alpha + beta type or beta type titanium alloy has poor high temperature resistance. Therefore, aiming at the high-temperature service working condition of the aerospace pressure-resistant structure, the development of a titanium alloy material with high modulus, low density, good ductility and toughness and good heat resistance is urgently needed.

Disclosure of Invention

Aiming at the problems and the defects in the prior art, the invention aims to provide an alpha-type titanium alloy with high specific modulus, heat resistance and easy forming and a preparation method thereof.

In order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows:

the invention provides an alpha-type titanium alloy with high specific modulus, heat resistance and easy forming, which comprises the following components in percentage by mass: 12.0 to 14.0 percent of Al, 3.5 to 6.0 percent of Zr, 3.0 to 6.0 percent of Sn3, 0.5 to 1.0 percent of B, 0.05 to 0.1 percent of rare earth elements, 0.10 to 0.25 percent of O, and the balance of Ti and inevitable impurity elements.

According to the α -type high specific modulus heat resistant easy-to-shape titanium alloy, preferably, the rare earth element is Gd.

The alpha-type high specific modulus heat-resistant easily-formed titanium alloy preferably contains aluminum equivalent [ Al [. sup.]_{When in use}13.7 to 16.0, wherein [ Al]_{When in use}The aluminum alloy is characterized by comprising the following components in percentage by mass, wherein the percentage is Al +% Sn/3+% Zr/6, and the percentage is the mass percentage of each element in the titanium alloy.

According to the alpha-type high specific modulus heat-resistant easily-formed titanium alloy, molybdenum equivalent [ Mo ] in the titanium alloy is preferable]_{When in use}Is 0.

According to the α -type titanium alloy with high specific modulus, heat resistance and easy forming, preferably, the impurity element is C, N, H, and the mass percentage of the impurity element in the titanium alloy is: c is less than or equal to 0.10 percent, N is less than or equal to 0.05 percent, and H is less than or equal to 0.01 percent.

The first aspect of the present invention provides a method for preparing the α -type titanium alloy with high specific modulus, heat resistance and easy forming, which is characterized by comprising the following steps:

(1) smelting and ingot casting: mixing the titanium alloy components according to the first aspect, and smelting and casting the prepared titanium alloy raw material to obtain an alloy cast ingot;

According to the preparation method, the smelting is preferably to smelt the titanium alloy raw material by adopting a vacuum consumable arc smelting technology.

According to the preparation method, the raw material of the titanium element is preferably industrial grade 1 titanium sponge during batching.

Compared with the prior art, the invention has the following positive beneficial effects:

(1) the content of low-density alpha stable element aluminum in the alpha-type high-specific-modulus heat-resistant easy-forming titanium alloy material provided by the invention is up to 12.0-14.0%, and no high-density beta stable element is added, so that the density of the alloy is greatly reduced, and the density rho of the prepared alpha-type high-specific-modulus heat-resistant easy-forming titanium alloy is less than or equal to 4.2g/cm³Is obviously lower than that of the traditional titanium alloy (4.5 g/cm)³)。

(2) The alpha-type high specific modulus heat-resistant easy-to-form titanium alloy is an alpha-type structure, has higher elastic modulus and good heat resistance; moreover, 0.5% -1.0% of B element is added into the titanium alloy to form a second phase TiB, so that the elastic modulus of the titanium alloy is further improved, the room-temperature elastic modulus E of the prepared alpha-type high-specific-modulus heat-resistant easy-forming titanium alloy is not less than 138GPa, and the high-temperature elastic modulus E at 600 ℃ is not less than 104GPa, which is far higher than the elastic modulus of the titanium alloy reported at present.

(3) As the element B is added into the titanium alloy, the plasticity and toughness of the alloy are greatly reduced due to the addition of the element B, and in order to avoid the reduction of the plasticity and toughness of the titanium alloy, the research of the application finds that 0.05-0.1% of Gd element is added into the titanium alloy, so that the plasticity and toughness of the titanium alloy can be greatly improved, the elongation A of the prepared alpha-type high specific modulus heat-resistant easily-formed titanium alloy at room temperature is more than or equal to 12%, and the elongation A at high temperature of 600 ℃ is more than or equal to 18%, so that the optimal matching of the elastic modulus and the plasticity and toughness of the titanium alloy is realized; in addition, the invention also discovers that 0.05-0.1% of Gd element is added into the alloy material, so that the coarsening resistance of the alloy at high temperature can be improved, the prepared titanium alloy has good thermal stability, the tensile strength Rm is more than or equal to 510MPa at 600 ℃, and the yield strength R is_p0.2≥620MPa。

(4) 3.5 to 6.0 percent of Zr element is added into the alpha-type titanium alloy material with high specific modulus, heat resistance and easy forming, so that the prepared titanium alloy has good welding performance, can realize welding methods such as electron beam, laser, manual TIG and the like, and has a welding coefficient more than or equal to 0.9.

In conclusion, the alpha-type high-specific-modulus heat-resistant easily-formed titanium alloy developed by the invention has high modulus, low density, good plastic toughness and heat resistance (the specific performance detection result is shown in table 1), breaks through the key technology of matching the elastic modulus and the plastic toughness of the titanium alloy, has high elastic modulus while ensuring the plastic toughness, has excellent performances such as low density and high temperature resistance, and has good technical application and market prospects in the fields of aerospace, naval equipment, weapon industry and the like.

TABLE 1 Performance test results of alpha-type high specific modulus heat-resistant easily-formable titanium alloy of the present invention

Detailed Description

The present invention will be described in further detail with reference to specific examples, but the scope of the present invention is not limited thereto.

Example 1: ti-13Al-3.5Zr-5Sn-1B-0.05Gd alloy

An alpha-type titanium alloy with high specific modulus, heat resistance and easy forming is prepared from the following components in percentage by mass: 13.0% of Al, 3.5% of Zr, 5.0% of Sn, 1.0% of B, 0.05% of Gd, 0.1% of O and the balance of Ti and inevitable impurity elements.

The preparation method of the alpha-type titanium alloy with high specific modulus, heat resistance and easy forming comprises the following specific steps:

(1) smelting and ingot casting: preparing materials according to the components of the titanium alloy, and carrying out three times of smelting on the prepared titanium alloy raw material by adopting a vacuum consumable arc smelting technology to prepare an alloy ingot;

(2) forging: cogging the alloy ingot prepared in the step (1) at 1100-1280 ℃, and forging for six times at 1020 +/-10 ℃, wherein the finish forging temperature is not lower than 860 ℃; then forging or rolling the alloy into a required forge piece or plate at 980 +/-10 ℃, wherein the finish forging temperature is not lower than 850 ℃.