1. The method for improving the performance of the silicide enhanced refractory high-entropy alloy by the thermal deformation process is characterized by comprising the following steps: the method comprises the following steps:

step one, sequentially putting Si, Ti, V, Nb and Ta into a non-consumable vacuum arc melting furnace according to the melting point from low to high;

step two, introducing inert protective gas after vacuumizing;

step three, repeatedly smelting the VaNbbTicTadSie alloy for more than 10 times, wherein the smelting current is 450-500A, the smelting voltage is 10-15V, and the smelting time is 3min each time; after the smelting is finished, cooling the alloy, and taking out the cast ingot to obtain VaNbbTicTadSie alloy;

step four, cutting the prepared VaNbbTicTadSie alloy into strips with the length of lmm, the width of wmm and the thickness of tmm, wrapping the VaNbbTicTadSie alloy by an alloy sheath with the thickness of nmm, and welding; wherein 30< l <100, 5< w <100, 5< t <100, 1< n <10,

fifthly, putting the coated alloy into a heat treatment furnace at 1100-1200 ℃, preheating for 10-20 min, and then rolling; controlling the rolling quantity to be about 10% each time, and obtaining VaNbbTicTadSie alloy with the deformation quantity of 60-90% through multi-pass rolling; removing the last rolling, and after each rolling, returning to the furnace and heating for 10-20 min;

and sixthly, cooling the alloy, removing the alloy sheath and the oxide skin, and obtaining the VaNbbTicTadSie alloy with excellent mechanical properties through structure regulation.

2. The method of improving the performance of a silicide enhanced refractory high entropy alloy by a hot deformation process as claimed in claim 1, wherein: the VaNbbTicTadSie alloy comprises five elements of titanium Ti, tantalum Ta, niobium Nb, vanadium V and silicon Si, and forms a VaNbbTicTadSie refractory high-entropy alloy; wherein a, b, c, d and d are atomic percentages of Ti, Ta, V, Nb and Si alloy respectively, a + b + c + d + e is 100, 20< a <40, 20< b <40, 20< c <40, 20< d <40, and 1< e < 10;

the VaNbbTicTadSie alloy is composed of Body Centered Cubic (BCC) phase and hexagonal M5Si3 silicide.

3. The silicide-reinforced refractory high-entropy alloy material of claim 1, wherein: the second step is realized by the following concrete method: pumping a non-consumable vacuum arc melting furnace to a vacuum state, and then introducing high-purity argon with the purity of 99.99 wt% as protective gas.

Background

The high-entropy alloy is an alloy design concept which has been raised in recent decades, and provides a new idea for the design of novel alloys. Researchers have combined this concept with refractory elements and have proposed the concept of refractory high entropy alloys. Research shows that the refractory high-entropy alloy has excellent high-temperature performance. For example, the high-temperature strength of the refractory high-entropy alloy such as WNbMoTa and WNbMoTaV can be maintained at 400MPa or more at a high temperature of 1600 ℃. The refractory high-entropy alloy is expected to replace the traditional nickel-based high-temperature alloy and become a new-generation high-temperature alloy, so that the service temperature of hot-end components of aeroengines and gas turbines is further increased, and the service performance of new-generation weaponry is improved.

However, the application of the refractory high-entropy alloy is severely restricted by the problems of higher density, poorer oxidation resistance, poorer plasticity and the like. Researches show that the addition of light elements such as Al, Cr, Si and the like can effectively reduce the density of the refractory high-entropy alloy and improve the oxidation resistance of the alloy. Meanwhile, due to the large negative mixing enthalpy between the elements and refractory elements, intermetallic compounds such as B2, Laves phases, silicide and the like are easily formed, and the strength of the alloy is improved. Among them, the silicide has the most obvious strengthening effect at high temperature. However, since the intermetallic compound is brittle and distributed at the grain boundary, the plastic deformability of the alloy is greatly reduced, and fracture easily occurs in practical applications. The invention utilizes a thermal deformation process to regulate and control the distribution of silicide in the silicide-reinforced refractory high-entropy alloy composite material, thereby realizing the purpose of optimizing the performance.

Disclosure of Invention

The invention aims to solve the problem of poor plasticity of silicide reinforced refractory high-entropy alloy, and provides a method for improving the performance of the silicide reinforced refractory high-entropy alloy through a thermal deformation process, which can realize synchronous improvement of the strength and the plastic deformation capacity of the silicide reinforced refractory high-entropy alloy.

In order to achieve the above object, the present invention is achieved by the following technical solutions.

A silicide reinforced refractory high-entropy alloy material comprises five elements of titanium (Ti), tantalum (Ta), niobium (Nb), vanadium (V) and silicon (Si) to form a VaNbbTicTadSie refractory high-entropy alloy. Wherein a, b, c, d and d are atomic percentages of Ti, Ta, V, Nb and Si alloy respectively, a + b + c + d + e is 100, 20< a <40, 20< b <40, 20< c <40, 20< d <40, and 1< e < 10;

the VaNbbTicTadSie alloy is composed of Body Centered Cubic (BCC) phase and hexagonal M5Si3 silicide.

The preparation method of the VaNbbTicTadSie alloy comprises the following steps:

the method comprises the following steps: selecting five elements of Ti, Ta, V, Nb and Si, accurately weighing the raw materials according to an alloy expression formula, and sequentially placing the raw materials into a copper crucible of a non-consumable vacuum arc melting furnace according to the sequence of melting points from low to high, namely Si, Ti, V, Nb and Ta.

Step two: and closing the furnace door, pumping the non-consumable vacuum arc melting furnace to a vacuum state, and introducing high-purity argon with the purity of 99.99 wt% as protective gas.

Step three: repeatedly smelting the VaNbbTicTadSie alloy for more than 10 times, wherein the smelting current is 450-500A, the smelting voltage is 10-15V, and the smelting time is 3min each time. And after the smelting is finished, taking out the cast ingot after the alloy is cooled.

The VaNbbTicTadSie alloy is processed by a hot deformation method, and the method comprises the following steps:

the method comprises the following steps: the prepared VaNbbTicTadSie alloy is cut into strips with the length of lmm, the width of wmm and the thickness of tmm, and the VaNbbTicTadSie alloy is wrapped by an alloy sheath with the thickness of nmm and welded. Wherein 30< l <100, 5< w <100, 5< t <100, 1< n <10,

step two: and (3) preheating the coated alloy in a heat treatment furnace at 1100-1200 ℃ for 10-20 min, and then rolling. The rolling amount is controlled to be about 10% each time, and the VaNbbTicTadSie alloy with the deformation amount of 60-90% is obtained through multi-pass rolling. And removing the last rolling, and after each rolling, returning to the furnace and heating for 10-20 min.

Step three: and cooling the alloy, and removing the alloy sheath and the oxide skin to obtain the VaNbbTicTadSie alloy with excellent mechanical property through structure regulation.

Advantageous effects

The as-cast VaNbbTicTadSie alloy has a BCC-structure matrix and a hexagonal-structure M5Si3 silicide phase. The BCC structure can ensure that the alloy has better plastic deformation capability, and the M5Si3 silicide phase ensures that the alloy has high strength. Wherein, the VNbTiTaSi system alloy has the strength higher than 500MPa under the compression condition of 1000 ℃, has 30 percent of compression fracture strain at room temperature and has better comprehensive mechanical property.

The thermal deformation method provided by the invention can crush the brittle silicide originally distributed in the crystal boundary and uniformly distribute the brittle silicide on the BCC toughness matrix. In addition, the hot rolling process enables the alloy grains to be refined. The refined crystal grains and the dispersed M5Si3 silicide enable the alloy to have higher strength and plastic deformation capability. The VNbTiTaSi system alloy after thermal deformation has the strength of 1300MPa under the condition of room-temperature stretching and has the elongation at break of 8 percent. Much higher than 1100MPa tensile strength and 1% elongation at break in the undeformed condition.

Drawings

FIG. 1 is a photograph of the structure and structure of an as-cast V22Nb25Ti28Ta22Si3 alloy, wherein (a) is the XRD pattern and (b) is the microstructure of the alloy;

FIG. 2 is an SEM picture of a hot deformed V22Nb25Ti28Ta22Si3 alloy;

FIG. 3 is the compressive mechanical properties of the as-cast V22Nb25Ti28Ta22Si3 alloy;

FIG. 4 is a comparison of the tensile mechanical properties of the V22Nb25Ti28Ta22Si3 alloy in the as-cast condition and after hot deformation.

Detailed Description

The invention is further described with reference to the following figures and examples.

Example 1

The embodiment is a method for improving the plastic deformability and strength of the silicide-reinforced refractory high-entropy alloy through thermal deformation. The refractory high-entropy alloy is a V22Nb25Ti28Ta22Si3 alloy composed of five elements of Ti, Ta, V, Nb, Si and the like, wherein the relative atomic percent of Ti is 28%, the relative atomic percent of Ta is 22%, the relative atomic percent of V is 22%, the relative atomic percent of Nb is 25%, and the relative atomic percent of Si is about 3%. The V22Nb25Ti28Ta22Si3 alloy has a BCC + M5Si3 structure, as shown in FIG. 1.

The preparation method of the V22Nb25Ti28Ta22Si3 refractory high-entropy alloy comprises the following steps:

the method comprises the following steps: selecting five elements of Ti, Ta, V, Nb and Si, accurately weighing the raw materials according to an alloy expression formula, and sequentially placing the raw materials into a copper crucible of a non-consumable vacuum arc melting furnace according to the sequence of melting points from low to high, namely Si, Ti, V, Nb and Ta.

Step two: and closing the furnace door, pumping the non-consumable vacuum arc melting furnace to a vacuum state, and introducing high-purity argon with the purity of 99.99 wt% as protective gas.

Step three: repeatedly smelting the V22Nb25Ti28Ta22Si3 alloy for 10 times, wherein the smelting current is 500A, the smelting voltage is 15V, and the smelting time is 3min each time. And after the smelting is finished, taking out the cast ingot after the alloy is cooled.

The V22Nb25Ti28Ta22Si3 alloy is processed by a hot deformation method, and the method comprises the following steps:

the method comprises the following steps: the V22Nb25Ti28Ta22Si3 alloy thus prepared was cut into a strip having a length of 30mm, a width of 10mm and a thickness of 10mm, and the V22Nb25Ti28Ta22Si3 alloy was wrapped with an alloy sheath having a thickness of 2mm and welded.

Step two: the coated alloy is preheated for 15min in a heat treatment furnace at 1150 ℃ and then rolled. The rolling amount is controlled to be about 10% each time, and V22Nb25Ti28Ta22Si3 alloy with the deformation amount of 80% is obtained through multi-pass rolling. The last rolling is removed, and after each rolling, the furnace is returned and heated for 15 min.

Step three: and cooling the alloy, and removing the alloy sheath and the oxide skin to obtain the V22Nb25Ti28Ta22Si3 alloy regulated and controlled by the structure.

XRD and SEM tests of the as-cast V22Nb25Ti28Ta22Si3 alloy are shown in FIG. 1. The results indicate that the as-cast V22Nb25Ti28Ta22Si3 alloy phase consists of a BCC phase and an M5Si3 phase distributed along grain boundaries. The compression test was performed on the as-cast V22Nb25Ti28Ta22Si3 alloy at room temperature and 1000 ℃ as shown in FIG. 3, and the results showed that the alloy had a yield strength of 1100MPa at room temperature, a strain at break of 30%, a yield strength of 500MPa at 1000 ℃ and no cracks were generated during the test. Tensile mechanical property tests are carried out on the as-cast V22Nb25Ti28Ta22Si3 alloy, and as shown in FIG. 4, the result shows that the tensile yield strength of the alloy is about 1050MPa, and the elongation at break is 1%. SEM test of the hot deformed V22Nb25Ti28Ta22Si3 alloy is shown in FIG. 2, and the result shows that the M5Si3 phase in the alloy is uniformly dispersed on the matrix. Tensile mechanical property tests are carried out on the thermally deformed V22Nb25Ti28Ta22Si3 alloy, as shown in FIG. 4, the results show that the tensile yield strength of the alloy is about 1300MPa, the elongation at break is 8%, the performance is remarkably improved compared with that of the as-cast alloy, and the refractory high-entropy alloy with high strength and high toughness is obtained.

Example 2

The embodiment is a method for improving the plastic deformability and strength of the silicide-reinforced refractory high-entropy alloy through thermal deformation. The refractory high-entropy alloy is a V22Nb25Ti28Ta22Si3 alloy composed of five elements of Ti, Ta, V, Nb, Si and the like, wherein the relative atomic percent of Ti is 28%, the relative atomic percent of Ta is 22%, the relative atomic percent of V is 22%, the relative atomic percent of Nb is 25%, and the relative atomic percent of Si is about 3%. The V22Nb25Ti28Ta22Si3 alloy has a BCC + M5Si3 structure, as shown in FIG. 1.

The preparation method of the V22Nb25Ti28Ta22Si3 refractory high-entropy alloy comprises the following steps:

the method comprises the following steps: selecting five elements of Ti, Ta, V, Nb and Si, accurately weighing the raw materials according to an alloy expression formula, and sequentially placing the raw materials into a copper crucible of a non-consumable vacuum arc melting furnace according to the sequence of melting points from low to high, namely Si, Ti, V, Nb and Ta.

Step two: and closing the furnace door, pumping the non-consumable vacuum arc melting furnace to a vacuum state, and introducing high-purity argon with the purity of 99.99 wt% as protective gas.

Step three: repeatedly smelting the V22Nb25Ti28Ta22Si3 alloy for 10 times, wherein the smelting current is 500A, the smelting voltage is 15V, and the smelting time is 3min each time. And after the smelting is finished, taking out the cast ingot after the alloy is cooled.

The V22Nb25Ti28Ta22Si3 alloy is processed by a hot deformation method, and the method comprises the following steps:

the method comprises the following steps: the V22Nb25Ti28Ta22Si3 alloy thus prepared was cut into a strip having a length of 30mm, a width of 10mm and a thickness of 10mm, and the V22Nb25Ti28Ta22Si3 alloy was wrapped with an alloy sheath having a thickness of 2mm and welded.

Step two: the coated alloy is preheated for 15min in a heat treatment furnace at 1150 ℃ and then rolled. The rolling amount is controlled to be about 10% each time, and the V22Nb25Ti28Ta22Si3 alloy with the deformation amount of 90% is obtained through multi-pass rolling. The last rolling is removed, and after each rolling, the furnace is returned and heated for 15 min.

Step three: and cooling the alloy, and removing the alloy sheath and the oxide skin to obtain the V22Nb25Ti28Ta22Si3 alloy regulated and controlled by the structure.

XRD and SEM tests were performed on the as-cast V22Nb25Ti28Ta22Si3 alloy. The phase composition of the V22Nb25Ti28Ta22Si3 alloy is BCC phase and M5Si3 phase distributed along grain boundaries. The compression test was performed on the as-cast V22Nb25Ti28Ta22Si3 alloy at room temperature and 1000 ℃ as shown in FIG. 3, and the results showed that the alloy had a yield strength of 1100MPa at room temperature, a strain at break of 30%, a yield strength of 500MPa at 1000 ℃ and no cracks were generated during the test. Tensile mechanical property tests are carried out on the as-cast V22Nb25Ti28Ta22Si3 alloy, and as shown in FIG. 4, the result shows that the tensile yield strength of the alloy is about 1050MPa, and the elongation at break is 1%. SEM test of the V22Nb25Ti28Ta22Si3 alloy after 90% of heat deformation shows that M5Si3 phase in the alloy is uniformly dispersed and distributed on the matrix. The tensile mechanical property test is carried out on the V22Nb25Ti28Ta22Si3 alloy which is subjected to 90% thermal deformation, the result shows that the tensile yield strength of the alloy is about 1200MPa, the fracture elongation is 10%, the performance is obviously improved compared with that of an as-cast state, and the refractory high-entropy alloy with high strength and high toughness is obtained.

Example 3

The embodiment is a method for improving the plastic deformability and strength of the silicide-reinforced refractory high-entropy alloy through thermal deformation. The refractory high-entropy alloy is a V20Nb27Ti30Ta20Si3 alloy composed of five elements of Ti, Ta, V, Nb, Si and the like, wherein the relative atomic percent of Ti is 30%, the relative atomic percent of Ta is 20%, the relative atomic percent of V is 20%, the relative atomic percent of Nb is 27%, and the relative atomic percent of Si is about 3%. The V20Nb27Ti30Ta20Si3 alloy has a BCC + M5Si3 structure.

The preparation method of the V20Nb27Ti30Ta20Si3 refractory high-entropy alloy comprises the following steps:

the method comprises the following steps: selecting five elements of Ti, Ta, V, Nb and Si, accurately weighing the raw materials according to an alloy expression formula, and sequentially placing the raw materials into a copper crucible of a non-consumable vacuum arc melting furnace according to the sequence of melting points from low to high, namely Si, Ti, V, Nb and Ta.

Step two: and closing the furnace door, pumping the non-consumable vacuum arc melting furnace to a vacuum state, and introducing high-purity argon with the purity of 99.99 wt% as protective gas.

Step three: repeatedly smelting the V20Nb27Ti30Ta20Si3 alloy for 10 times, wherein the smelting current is 500A, the smelting voltage is 15V, and the smelting time is 3min each time. And after the smelting is finished, taking out the cast ingot after the alloy is cooled.

The V20Nb27Ti30Ta20Si3 alloy is processed by a hot deformation method, and the method comprises the following steps:

the method comprises the following steps: the V20Nb27Ti30Ta20Si3 alloy thus prepared was cut into a strip having a length of 30mm, a width of 10mm and a thickness of 10mm, and the V20Nb27Ti30Ta20Si3 alloy was wrapped with an alloy sheath having a thickness of 2mm and welded.

Step two: the coated alloy is preheated for 15min in a heat treatment furnace at 1150 ℃ and then rolled. The rolling amount is controlled to be about 10% each time, and the V20Nb27Ti30Ta20Si3 alloy with the deformation amount of 80% is obtained through multi-pass rolling. The last rolling is removed, and after each rolling, the furnace is returned and heated for 15 min.

Step three: and cooling the alloy, and removing the alloy sheath and the oxide skin to obtain the V20Nb27Ti30Ta20Si3 alloy subjected to structure regulation.

XRD and SEM tests of the cast V20Nb27Ti30Ta20Si3 alloy show that the phase composition is BCC phase and M5Si3 phase distributed along grain boundaries. The compression test of the cast V20Nb27Ti30Ta20Si3 alloy at room temperature and 1000 ℃ shows that the yield strength of the alloy at room temperature is 1050MPa, the breaking strain is 35 percent, the yield strength at 1000 ℃ is 480MPa, and no crack is generated in the test process. Tensile mechanical property tests are carried out on the as-cast V20Nb27Ti30Ta20Si3 alloy, and the results show that the tensile yield strength of the alloy is about 1000MPa, and the elongation at break is 1%. SEM test of V20Nb27Ti30Ta20Si3 alloy with 80% thermal deformation shows that M5Si3 phase in the alloy is uniformly dispersed on a matrix. The tensile mechanical property test is carried out on the V20Nb27Ti30Ta20Si3 alloy with 80% thermal deformation, the result shows that the tensile yield strength of the alloy is about 1250MPa, the fracture elongation is 10%, the performance is obviously improved compared with the cast state, and the refractory high-entropy alloy with high strength and high toughness is obtained.

The foregoing is a description of the preferred embodiments of the present invention. It should be noted that the present invention is not limited to the above embodiments, and any modifications, equivalent replacements, or improvements that can be made to the present invention are included in the protection scope of the present invention when the scope of the claims, the summary of the invention, and the accompanying drawings are satisfied.