阅读说明：本技术 一种亚微米析出相ZrTiNbTaSn难熔高熵合金及其制备方法 (Submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy and preparation method thereof ) 是由 朱正旺 周永康 张海峰 张宏伟 付华萌 李宏 王爱民 张龙 李正坤 李松涛 于 2021-07-21 设计创作，主要内容包括：本发明涉及一种亚微米析出相ZrTiNbTaSn难熔高熵合金及其制备方法,属于金属材料技术领域。该难熔高熵合金的组成元素为Zr、Ti、Nb、Ta、Sn,各组分按原子百分比为：Zr 44-48％,Ti 11-15％,Nb 24-28％,Ta8-12％,Sn 2-6％。该合金铸态下为单一的BCC结构,组织状态为树枝状,通过热处理可析出亚微米尺寸的析出相。(The invention relates to a submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy and a preparation method thereof, belonging to the technical field of metal materials. The refractory high-entropy alloy comprises the following components in percentage by atom: 44-48% of Zr, 11-15% of Ti, 24-28% of Nb, 8-12% of Ta and 2-6% of Sn. The alloy has a single BCC structure in an as-cast state and a dendritic structure state, and can precipitate a precipitated phase with a submicron size through heat treatment.)

1. A submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy is characterized in that: the ZrTiNbTaSn refractory high-entropy alloy comprises the following components in percentage by atom: 44-48% of Zr, 11-15% of Ti, 24-28% of Nb, 8-12% of Ta and 2-6% of Sn.

2. The submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy as claimed in claim 1, wherein: the refractory high-entropy alloy structure is a single BCC structure at room temperature, and a precipitated phase with a submicron size can be precipitated through heat treatment.

3. The submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy according to claim 2, characterized in that: the cooling mode after the heat treatment is furnace cooling.

4. The submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy according to claim 1 or 2, characterized in that: the purity of the refractory high-entropy alloy constituent elements of zirconium, titanium, niobium, tantalum and tin is more than or equal to 99.9 wt%.

5. A method for preparing the submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy as claimed in claims 1 and 2, characterized by comprising the following steps:

1) converting the atomic percentage of the chemical components of the raw materials into mass percentage, and batching according to the mass percentage;

2) putting raw materials of zirconium, titanium and tin into a copper crucible of a vacuum arc furnace according to the sequence that the melting point is lower than the lower melting point and the melting point is higher than the upper melting point; placing niobium and tantalum in other copper crucibles of a vacuum arc furnace in the order of lower melting point and higher melting point; titanium sponge is put into the rest copper crucible; vacuumizing and then filling argon;

3) carrying out heat treatment on the ZrTiNbTaSn refractory high-entropy alloy ingot at 1180-1220 ℃ for 1420-1460 min, and carrying out furnace cooling.

6. The preparation method of the submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy according to claim 5, which is characterized by comprising the following steps: in the step 1), Zr, Ti, Nb and Ta and Sn are used as raw materials, namely zirconium sponge, titanium sponge, niobium chips and granular particles.

7. The preparation method of the submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy according to claim 5, which is characterized by comprising the following steps: in step 2), the vacuum degree of the vacuum furnace is 3.5 multiplied by 10^-3After Pa, filling high-purity argon of-0.08 MPa, and arc striking to smelt ZrTiNbTaSn refractory high-entropy alloy; firstly, smelting an intermediate alloy of Zr-Ti-Sn and Nb-Ta; the master alloys are then melted together.

8. The preparation method of the submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy according to claim 5, which is characterized by comprising the following steps: in the step 2), opening magnetic stirring in the smelting process, and smelting the alloy ingot for at least 7 times.

9. The preparation method of the submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy according to claim 5, which is characterized by comprising the following steps: in step 3), the mixture is first heated to 1000 ℃ at a rate of 10 ℃/min and then heated to 1200 ℃ at a rate of 5 ℃/min for heat treatment.

Technical Field

The invention relates to the field of metal materials and preparation thereof, in particular to a submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy and a preparation method thereof.

Background

The development of innovative metallurgical processes inevitably requires a breakthrough from the traditional metallurgical technology. This means that the concept of materials needs to be updated and adapted so that new materials with enhanced performance can be presented. Among the various exploration methods, "high entropy alloys" (HEA) have attracted a wide range of attention.

The high-entropy alloy has the same strengthening method as the traditional alloy: precipitation strengthening, solid solution strengthening, fine grain strengthening and dislocation strengthening. The refractory high-entropy alloy has a typical Body Centered Cubic (BCC) structure, the crystal structure does not have phase change in the heat treatment process, the crystal structure is a single crystal structure in general, the phase stability is high, and a precipitated phase is difficult to form. Refractory high entropy alloys generally achieve performance improvements in other strengthening ways. Therefore, a great deal of work is required for preparing and realizing the submicron-nanoscale precipitated phase high-entropy alloy.

Disclosure of Invention

The invention aims to provide a submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy and a preparation method thereof.

The technical scheme of the invention is as follows:

a submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy is characterized in that: the ZrTiNbTaSn refractory high-entropy alloy comprises the following components in percentage by atom: 44-48% of Zr, 11-15% of Ti, 24-28% of Nb, 8-12% of Ta and 2-6% of Sn.

The alloy has a single BCC structure (at room temperature) in an as-cast state and a dendritic structure. After a certain heat treatment process (heat treatment is carried out at 1180-1220 ℃ for 1420-1460 min, and furnace cooling), a large amount of submicron phases can be precipitated, and the size of the precipitated phases is 263.3 +/-50.7 nm.

The purity of the components of zirconium, titanium, niobium, tantalum and tin in the refractory high-entropy alloy is more than or equal to 99.9%.

The preparation method of the submicron precipitated phase ZrTiNbTaSn refractory high-entropy alloy is characterized by comprising the following steps of:

1) converting the atomic percentage of the chemical components of the raw materials into mass percentage, and batching according to the mass percentage;

2) putting raw materials of zirconium, titanium and tin into a copper crucible of a vacuum arc furnace according to the sequence that the melting point is lower than the lower melting point and the melting point is higher than the upper melting point; placing niobium and tantalum in other copper crucibles of a vacuum arc furnace in the order of lower melting point and higher melting point; titanium sponge is put into the rest copper crucible; vacuumizing and then filling argon;

3) carrying out heat treatment on the ZrTiNbTaSn refractory high-entropy alloy ingot at 1200 +/-20 ℃ for 1440 +/-20 min, and carrying out furnace cooling.

As a preferred technical scheme:

in the step 1), Zr serving as a raw material, Ti serving as sponge titanium, Nb serving as niobium chips and Ta and Sn serving as particles; the quality of the raw materials is controlled to three bits after a decimal point, and in order to ensure the purity of the raw materials, the raw materials are firstly cleaned by ultrasonic in acetone for 20min and then cleaned by ultrasonic in alcohol for 20 min.

In step 2), the vacuum degree of the vacuum furnace is 3.5 multiplied by 10^-3After Pa, filling high-purity argon of-0.08 MPa, and arc striking to smelt ZrTiNbTaSn refractory high-entropy alloy; firstly, smelting an intermediate alloy of Zr-Ti-Sn and Nb-Ta; the master alloys are then melted together. And opening magnetic stirring in the smelting process, and smelting the alloy ingot for at least 7 times.

In the step 3), when the ingot alloy is subjected to heat treatment, a quartz glass tube is firstly used for vacuum packaging to prevent oxidation. Firstly heating to 1000 ℃ at the speed of 10 ℃/min, then heating to 1200 ℃ at the speed of 5 ℃/min for heat treatment, and furnace cooling.

Compared with the prior art, the invention has the advantages that:

the invention designs a new alloy system through the selection of alloy elements, and the addition of Sn element plays a role in solid solution strengthening. Compared with the existing refractory high-entropy alloy, the refractory high-entropy alloy prepared by the invention has the room-temperature compressive strength of more than 3GPa, the yield strength of 1.3GPa and the plasticity of more than 50%, and the submicron phase is precipitated by a simple heat treatment method, and the yield strength of 1.5 GPa. Meanwhile, the alloy is simple in preparation process, can be prepared by adopting the traditional electric arc melting, is simple in heat treatment process, greatly reduces the cost, and realizes energy conservation and emission reduction.

Drawings

FIG. 1 is a microstructure of a ZrTiNbTaSn refractory high-entropy alloy;

FIG. 2 is a microstructure of a ZrTiNbTaSn refractory high-entropy alloy after heat treatment;

FIG. 3 is a size distribution diagram of precipitated phases of a ZrTiNbTaSn refractory high-entropy alloy;

FIG. 4 is a room temperature compressive engineering stress-strain diagram of a ZrTiNbTaSn refractory high-entropy alloy.

Detailed Description

The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Examples

The preparation method of the ZrTiNbTaSn alloy comprises the following specific steps:

1) preparing raw materials: the refractory high-entropy alloy developed by the invention comprises Zr, Ti, Nb, Ta and Sn. The alloy preparation is converted into a mixture by mass percent according to the atomic percent of chemical components, and the purity of the selected 5 elements is higher than 99.9 percent. Zr is sponge zirconium, Ti is sponge titanium, Nb is niobium scrap, and Ta and Sn are granular.

Pretreating raw materials before smelting: ultrasonically cleaning with acetone for 20min, removing oil stains on the surfaces of Nb, Ta and Sn, ultrasonically cleaning with alcohol for 20min, and drying in a drying oven.

2) Preparing an alloy: the invention adopts a vacuum arc furnace to smelt the alloy. Raw materials of Zr, Ti and Sn are separately placed in a copper crucible, and Nb and Ta are separately placedIn other copper crucibles, master alloys were prepared. Oxygen-absorbing titanium sponge is added into the vacant copper crucible. Vacuum-pumping to 3.5X 10^-3Pa, then filling high-purity argon to-0.08 MPa. And (3) opening magnetic stirring in the smelting process to ensure that the chemical components are uniform. And putting the smelted intermediate alloys together, and smelting the final alloy. The melting was repeated 7 times.

3) And (3) finishing alloy smelting, filling air after the furnace body is cooled, opening a furnace door, taking out an alloy ingot to obtain an as-cast alloy, and carrying out heat treatment and structural characterization. Firstly heating to 1000 ℃ at the speed of 10 ℃/min, then heating to 1200 ℃ at the speed of 5 ℃/min, carrying out heat treatment on the cast ingot at the temperature of 1200 +/-20 ℃ for 1440 +/-20 min, and cooling in a furnace.

TABLE 1 actual composition ratio of ZrTiNbTaSn alloy

Element	Zr	Ti	Nb	Ta	Sn
						At％	45.55	13.56	25.44	10.99	4.46

Referring to fig. 1, it can be seen that the refractory high entropy alloy of the present embodiment is dendritic and intergranular in the as-cast state. Referring to fig. 2, it can be seen that the heat treated alloy precipitates a large amount of submicron-sized precipitates within the crystal. Referring to FIG. 3, it can be seen that the sizes of the precipitated phases are normally distributed, and the average size is 263.3 + -50.7 nm. Referring to FIG. 4, it can be seen that the as-cast yield strength is 1.3GPa, the compressive strength exceeds 3GPa, and the plasticity is > 50%. The yield strength after heat treatment was 1.5 GPa. Therefore, the composite material has excellent mechanical properties and microstructure.

Example 2

The difference from the embodiment 1 is that the actual composition ratio of the ZrTiNbTaSn alloy is shown in the table 2.

TABLE 2 actual composition ratio of ZrTiNbTaSn alloy

Element	Zr	Ti	Nb	Ta	Sn
						At％	44.54	14.62	26.13	9.42	5.29

The alloy is dendritic crystal and intercrystalline structure in an as-cast state, and a large amount of precipitated phases with submicron sizes can be precipitated in the crystal after heat treatment. The yield strength at room temperature under the casting state is 1.35GPa, the compressive strength exceeds 3GPa, and the plasticity is more than 50 percent. The yield strength after heat treatment is 1.55GPa, the average precipitated phase size is 259.3 +/-48.7, and the alloy has excellent mechanical properties and microstructure.

The invention is not the best known technology.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.