阅读说明：本技术 一种轻质超韧高强NbTiVAlxZry铸态高熵合金 (Light super-tough high-strength NbTiVAlxZry as-cast high-entropy alloy ) 是由 汪涛 许金亮 陆永发 张陕南 王春雨 未文超 于 2018-10-22 设计创作，主要内容包括：本发明公开了一种轻质超韧高强NbTiVAlxZry铸态高熵合金,所述轻质超韧高强NbTiVAlxZry铸态高熵合金,其中Nb：Ti：V：Al：Zr的摩尔比依次为：1.0：1.0：1.0：0.2～0.3：0.4～0.5。制备工艺如下：选用纯度高于99.0wt.%的Nb、Ti、V、Al、Zr五种元素作为原料进行配料,选用能量束熔炼技术或感应熔炼技术制备该铸态高熵合金。本发明所述高熵合金组织均匀,表现出优异的综合力学性能,具有较高的强度和较大的塑性,其屈服强度为1062MPa～1469MPa,抗压强度为1371MPa～1993MPa,断裂应变35%～57%,密度为6.15g·cm<Sup>-3</Sup>～6.25g·cm<Sup>-3</Sup>,应用前景广阔。(The invention discloses a light super-tough high-strength NbTiVAlxZry as-cast high-entropy alloy, which is characterized in that Nb: ti: v: al: the mol ratio of Zr is as follows: 1.0: 1.0: 1.0: 0.2-0.3: 0.4 to 0.5. The preparation process comprises the following steps: five elements of Nb, Ti, V, Al and Zr with the purity higher than 99.0wt.% are selected as raw materials to be mixed, and an energy beam melting technology or an induction melting technology is selected to prepare the as-cast high-entropy alloy. The high-entropy alloy has uniform structure, excellent comprehensive mechanical property, higher strength and larger plasticity, the yield strength is 1062-1469 MPa, the compressive strength is 1371-1993 MPa, the fracture strain is 35-57%, and the density is 6.15 g.cm ‑3 ～6.25g•cm ‑3 And the application prospect is wide.)

1. The light super-tough high-strength NbTiVAlxZry as-cast high-entropy alloy is characterized in that Nb: ti: v: al: the molar ratio of Zr is 1.0: 1.0: 1.0: 0.2-0.3: 0.4 to 0.5.

2. The as-cast high entropy alloy of claim 1, wherein when Nb: ti: v: al: the molar ratio of Zr is 1.0: 1.0: 1.0: 0.3: at 0.5, the alloy takes a BCC structural phase as a main phase and takes an ordered B2 structural phase as an auxiliary phase.

3. The as-cast high-entropy alloy according to claim 1, wherein the alloy is single-phase with a BCC structure phase when the molar ratio of Nb to Ti to V to Al to Zr is 1.0: 1.0: 1.0: 0.2: 0.4 ~ 0.5.5, respectively.

4. The as-cast high entropy alloy of claim 1, wherein when Nb: ti: v: al: the molar ratio of Zr is 1.0: 1.0: 1.0: 0.3: at 0.4, the alloy is single-phase with BCC structure phase.

5. The as-cast high-entropy alloy according to any one of claims 1 to 4, wherein the as-cast high-entropy alloy has a yield strength of 1062MPa to 1469MPa, a compressive strength of 1371MPa to 1993MPa, a strain at break of 35% to 57%, and a density of 6.15 g.cm^-3～6.25g•cm^-3。

6. The method of preparing the as-cast NbTiVAlZry high entropy alloy as claimed in any of claims 1 to 5, comprising:

selecting five elements of Nb, Ti, V, Al and Zr as raw materials to prepare materials;

removing surface oxide scales of the raw materials of Nb, Ti, V, Al and Zr, and cleaning and drying;

and step three, obtaining the NbTiVAlxZry as-cast high-entropy alloy through smelting.

7. The method of claim 6, wherein in step one, the purity of the metal feedstock is greater than 99.0 wt.%.

8. The method as claimed in claim 6, wherein in step three, the NbTiVAlxZry as-cast high entropy alloy is obtained by melting by energy beam melting or induction melting.

9. Use of the as-cast high entropy alloy of NbTiVAlxZry according to any of claims 1-5 as a light or/and super tough or/and high strength structural material.

10. The use of claim 9, wherein the lightweight structural material is not greater than 7g/cm³The material of (1).

Technical Field

The invention relates to the field of metal materials and preparation thereof, and provides a light super-tough high-strength NbTiVAlxZry as-cast high-entropy alloy.

Background

The high-entropy alloy is a super solid solution alloy and is generally formed by combining five or more metal or nonmetal elements in an equal ratio or a nearly equal atomic ratio. To break through the limitations of research, the researchers have extended the definition of high entropy alloys to the extent that the proportion of each principal element in the alloy in the system can be between 5at.% and 35 at.%. Different from the traditional alloy, any element in the high-entropy alloy cannot become a leading element of an alloy system, and the characteristic of the whole alloy is the result of common leadership of various elements; the traditional alloy design concept considers that the more the alloy component number is, the more easily the complex phases such as brittle intermetallic compounds are formed, the alloy research is hindered, the alloy application is limited, and a large number of experiments show that: the lattice distortion effect, the delayed diffusion effect and the cocktail effect of the high-entropy alloy enable the alloy to integrate high strength, high hardness, high wear resistance and corrosion resistance, and the comprehensive mechanical property is excellent; the high-entropy alloy has more flexible component design, and can realize the regulation and control of material density, mechanical property and energy characteristic so as to meet the requirements of high-strength and high-toughness structural materials under different use conditions.

Nb-Ti-V-Al-Zr is a novel light high-entropy alloy system proposed by Russian Stepanov N D professor, and aims to reduce the density of the high-entropy alloy while simultaneously considering the excellent mechanical properties of the high-entropy alloy, so that the high-entropy alloy can be applied to wider fields. Stepanov N D Al was introduced into NbTiVZr high entropy alloy, NbTiVZrAlx (x =0,0.5,1.0,1.5) high entropy alloy was designed and found that when Al content exceeded 0.5, the strength of the alloy at room temperature only slightly increased (the fracture strength of Al0.5NbTiVZr was 1100MPa, the fracture strength of Al1.5NbTiVZr was 1310 MPa), but the plasticity significantly decreased (the plastic strain of Al0.5NbTiVZr was only 4%), even completely lost (Al1.5TiVZr no plastic strain) [ Stepanov N D, Yurchekon Y, Shaysultanov D G, et Al. Effect of Al on structure and mechanical properties of AlxNbVZr (x =0,0.5,1,1.5) high entropy J [ science ] analysis J.1183, 1194 ] Technology.

Yu. Yurchenko et al studied AlNbTiVZrx (x =0,0.1,0.25,0.5,1.0,1.5) high entropy alloys and found that the majority of the series exhibited fracture phenomena at compressive strains below 15% after homogenizing annealing at 1200 ℃ and exhibited poor room temperature plasticity [ Yurchenko N Y, Stepanov N D, zheherebwov SV, et al Structure and mechanical properties of B2 ordered purified recycled nbtivbtivzrx (x = 0-1.5) high-entropy alloys [ J ] Materials Science and engineering a, 2017, 704: 82-90 ].

In summary, even though the developed alloys have excellent room temperature strength, the ductility and toughness properties are poor, and the plastic forming is difficult, so that the practical application of the alloys as high-strength high-toughness structural materials is limited.

Disclosure of Invention

Aiming at the problem of poor matching of strength, plasticity and toughness of the existing Nb-Ti-V-Al-Zr light high-entropy alloy at room temperature, the invention aims to provide a light super-tough high-strength NbTiVAlxZry as-cast high-entropy alloy.

In order to realize the purpose of the invention, the following technical scheme is provided:

a light super-tough high-strength NbTiVAlxZry as-cast high-entropy alloy is disclosed, wherein Nb: ti: v: al: the molar ratio of Zr is 1.0: 1.0: 1.0: 0.2-0.3: 0.4 to 0.5.

Preferably, when Nb: ti: v: al: the molar ratio of Zr is 1.0: 1.0: 1.0: 0.3: at 0.5, the alloy takes a BCC structural phase as a main phase and takes an ordered B2 structural phase as an auxiliary phase.

Preferably, the alloy has a BCC structure phase as a single phase when the molar ratio of Nb to Ti to V to Al to Zr is 1.0: 1.0: 1.0: 0.2: 0.4 ~ 0.5.5, respectively.

Preferably, when Nb: ti: v: al: the molar ratio of Zr is 1.0: 1.0: 1.0: 0.3: at 0.4, the alloy is single-phase with BCC structure phase.

The preparation method of the NbTiVAlxZry as-cast high-entropy alloy comprises the following steps:

selecting five elements of Nb, Ti, V, Al and Zr as raw materials to prepare materials;

removing surface oxide skins of the raw materials of Nb, Ti, V, Al and Zr, and cleaning and drying for later use;

and step three, obtaining the NbTiVAlxZry as-cast high-entropy alloy through smelting.

Furthermore, in the step one, the purity of the metal raw material is higher than 99.0 wt.%.

Further, in the third step, the NbTiVAlxZry as-cast high-entropy alloy is obtained by adopting an energy beam melting technology or an induction melting technology.

The NbTiVAlxZry as-cast high-entropy alloy is applied as a light or/and super-tough or/and high-strength structural material.

Further, the light structural material is not more than 7g/cm³The material of (1).

Furthermore, the high-strength structural material is a material with the strength of more than 1000 MPa.

Furthermore, the super-tough structure material is a material with a compressive fracture strain not less than 35%.

Compared with the prior art, the invention has the beneficial effects that:

the invention solves the problem of poor combination of strength, plasticity and toughness of the Nb-Ti-V-Al-Zr light high-entropy alloy at room temperature by simultaneously changing the contents of Al and Zr, and the prepared high-entropy alloy has uniform structure, excellent comprehensive mechanical property, higher strength and larger plasticity, the yield strength of 1062-1469 MPa, the compressive strength of 1371-1993 MPa, the fracture strain of 35-57 percent and the density of 6.15 g.cm^-3～6.25g•cm^-3(ii) a When the high-entropy alloy is Nb: ti: v: al: the mol ratio of Zr is as follows: 1.0: 1.0: 1.0: 0.3: at 0.4, the yield strength of the high-entropy alloy is 1284MPa, the compressive strength is 1785MPa, and the fracture strain is 56.37%; nb: ti: v: al: the mol ratio of Zr is as follows: 1.0: 1.0: 1.0: 0.3: at 0.5, the yield strength of the high-entropy alloy is 1469MPa, the compressive strength is 1993MPa, the fracture strain is 39.12 percent, and the application prospect is wide.

Drawings

FIG. 1 is an X-ray diffraction (XRD) spectrum of an as-cast NbTiVAlxZry high entropy alloy.

FIG. 2 is a room temperature quasi-static compressive engineering stress-strain curve of an as-cast NbTiVAlxZry high entropy alloy.

FIG. 3 shows the compression fracture morphology of the as-cast NbTiVAlxZry high entropy alloy, wherein a represents the third embodiment, b represents the first embodiment, c represents the second embodiment, and d represents the fourth embodiment.

Detailed Description

The present invention is further illustrated in detail by the following examples: