EP3896183A1

EP3896183A1 - Lightweight high-entropy alloy having high strength and high plasticity and preparation method therefor

Info

Publication number: EP3896183A1
Application number: EP19895264.0A
Authority: EP
Inventors: Yunfei XUE; Songshen CHEN; Liang Wang; Tangqing CAO; Benpeng WANG; Fuchi WANG; Lu Wang
Original assignee: Beijing Institute of Technology BIT
Current assignee: Beijing Institute of Technology BIT
Priority date: 2018-12-10
Filing date: 2019-11-19
Publication date: 2021-10-20
Also published as: EP3896183A4; CN109402482B; CN109402482A; WO2020118802A1

Abstract

The invention relates to a lightweight high-entropy alloy with high strength and high plasticity and a preparation method thereof, belonging to the fields of metal materials and preparation thereof. The high-entropy alloy is mainly composed of Ti, Zr, V, Nb and M, wherein M is one or more of Al, Hf, Cr, Fe, Mg, Be, Li, Mo, Co, Ni, Si, B, O and N. By regulating contents of all the elements, the high-entropy alloy has low density, high strength and high plasticity so as to have a huge application potential in the field of engineering. Moreover, the preparation method of the high-entropy alloy is easy to operate as well as safe and reliable, the adopted raw materials are nontoxic and harmless, and the high-entropy alloy is economical and practical.

Description

TECHNICAL FIELD

The present invention relates to a lightweight high-entropy alloy with high strength and high plasticity and a preparation method thereof, belonging to the fields of metal materials and preparation thereof.

BACKGROUND

A high-entropy alloy is an alloy formed by combining five or more elements in an approximate equi-atomic ratio and is also referred to as a multi-principal-element and high-irregularity alloy. Due to a multi-principal-element effect (a high-entropy effect, a lattice distortion effect, a lagged diffusion effect and a cocktail effect), the high-entropy alloy shows a metallurgical-physical effect mechanism different from that of traditional alloy and further shows a series of excellent properties such as outstanding high-temperature strength, good low-temperature plasticity, good wear resistance, good corrosion resistance and excellent radiation resistance. With the development of research, the range of the high-entropy alloy is widened, elements are no longer limited to five or more than five elements, the atomic proportion also gradually deviates from an equi-atomic ratio, and the designability of the alloy is greatly improved.
At present, researchers generally adopt a method for adding a great number of low-density metals in first three periods to reduce the density of the high-entropy alloy, which results in the production of a great number of second phases. Although relatively low density, high hardness and high compression strength can be achieved, the plasticity is seriously sacrificed, which greatly limits the application in the engineering.

SUMMARY

In view of this, the present invention provides a lightweight high-entropy alloy with high strength and high plasticity and a preparation method thereof. The high-entropy alloy has low density, high strength and high plasticity so as to have a huge application potential in the field of engineering. Moreover, the preparation method of the high-entropy alloy is easy to operate as well as safe and reliable, and the high-entropy alloy is economical and practical.
The purpose of the present invention is achieved through the following technical solutions.
Provided is a lightweight high-entropy alloy with high strength and high plasticity. The high-entropy alloy is marked as Ti_aZr_bV_cNb_dM_x according to an atomic number ratio, M is one or more of Al, Hf, Cr, Fe, Mg, Be, Li, Mo, Co, Ni, Si, B, O and N, wherein 25<a≤65, 0<b≤55, 0≤c<25, 0<d≤35, 0≤x<20, a+b+c+d+x=100, and c and x cannot be 0 at the same time.
Further, in Ti_aZr_bV_cNb_dM_x, 25<a≤60, 15≤b≤50, 0≤c <25, 5≤d≤30, 0≤x <20, a+b+c+d+x=100, and c and x cannot be 0 at the same time.
Further, M is preferably one or more of Al, Hf, Cr, Fe, Mg, Be, Li, Mo, Co and Ni.
A preparation method of the high-entropy alloy provided by the present invention includes the following steps:

step 1, placing clean elemental raw materials Ti, Zr, V, Nb and M into a smelting furnace of which the vacuum degree is smaller than or equal to 2.5×10^-3 Pa, and filling the smelting furnace with a protective gas; then, performing smelting, and cooling an alloy liquid generated by smelting to obtain an alloy ingot; and overturning the alloy ingot, and performing repeated smelting for more than three times to ensure that components are uniform to obtain a high-entropy alloy ingot; and
step 2, sealing the high-entropy alloy ingot in an argon-filled quartz tube, performing solution treatment at the temperature of 900-1200°C, and keeping the temperature for 1-12 h to obtain the high-entropy alloy.

Further, purities of the elemental raw materials Ti, Zr, V, Nb and M are respectively greater than or equal to 99.7wt%.
Further, the smelting furnace is preferably an electric arc smelting furnace.
Further, the protective gas is preferably argon.
Beneficial effects:

(1) the high-entropy alloy of the present invention is composed of Ti, Zr, V, Nb and M, and by regulating contents of all the elements, the high-entropy alloy has the property advantages of low density, high strength and high plasticity so as to have a huge application potential in the field of engineering; and
(2) the preparation method of the present invention is easy to operate as well as safe and reliable, and the adopted raw materials are nontoxic, harmless and easily available.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a comparison diagram of X-ray diffractometer (XRD) spectrums of high-entropy alloys prepared in Embodiments 1-6;
Fig. 2 is a metallographic diagram of a high-entropy alloy Ti₆₀Zr₂₀V₃Nb₁₇ prepared in Embodiment 1;
Fig. 3 is a metallographic diagram of a high-entropy alloy Ti₃₀Zr₂₇V₁₈Nb₂₅ prepared in Embodiment 2;
Fig. 4 is a metallographic diagram of a high-entropy alloy Ti₅₀Zr₁₈V₁₂Nb₁₆Al₄ prepared in Embodiment 3;
Fig. 5 is a metallographic diagram of a high-entropy alloy Ti₄₀Zr₂₃V₁₃Nb₁₉Al₅ prepared in Embodiment 4;
Fig. 6 is a metallographic diagram of a high-entropy alloy Ti₃₀Zr₄₅Nb₇Al₈Hf₁₀ prepared in Embodiment 5;
Fig. 7 is a metallographic diagram of a high-entropy alloy Ti₅₀Zr₂₅V₇Nb₁₂Al₅Fe₁ prepared in Embodiment 6; and
Fig. 8 is a comparison diagram of quasi-static tensile engineering stress-strain curves of the high-entropy alloys prepared in Embodiments 1-6.

DETAILED DESCRIPTION

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, wherein the methods are conventional methods if they are not especially specified, and the raw materials are commercially available if they are not especially specified.
In the following embodiments:

high-vacuum non-consumable electric arc smelting furnace: DHL-400 high-vacuum non-consumable electric arc smelting furnace produced by SKY Technology Development Co., Ltd, CAS (Chinese Academy of Sciences);
phase analysis: an X-ray diffractometer (XRD) spectrum of the prepared high-entropy alloy is measured by adopting a Rigaku Smartlab X-ray Diffractometer, wherein a Kα ray on a Cu target is adopted, a working voltage is 40 kV, a working current is 110 mA, a scanning angle ranges from 20° to 90°, a scanning speed is 5°/min, a step length is 0.02°, and a measured angle error is smaller than 0.01°; and the size of a specimen measured by the XRD is 10 mm×10 mm×5 mm; and firstly, six surfaces are ground to be flat with 240# abrasive paper, and then, an irradiated surface is sequentially ground with 400# abrasive paper, 600# abrasive paper, 800# abrasive paper, 1000# abrasive paper, 1200# abrasive paper, 1500# abrasive paper, and 2000# abrasive paper;
microstructure: a microstructure of the prepared high-entropy alloy in a solution state is observed by adopting an Axio observer Aim research-grade metalloscope produced by the Deiss company in Germany, wherein the size of a metallographic specimen is 10 mm×10 mm×5 mm; and the metallographic specimen is firstly mounted by using a hot mounting press, then, is polished sequentially with 400# abrasive paper, 600# abrasive paper, 800# abrasive paper, 1000# abrasive paper, 1200# abrasive paper, 1500# abrasive paper, 2000# abrasive paper, 3000# abrasive paper, 5000# abrasive paper, and 7000# abrasive paper, and then, is polished with a silicon dioxide suspension with the particle size of 0.02 µm, and is finally soaked in a corrosive agent containing HF, HNO₃ and H₂O in a volume ratio of 1:3:20 for 5-30 s;
density measurement: the density of the prepared high-entropy alloy is measured by adopting a hydrostatic weighing method according to the standard GB/T1423-1996; firstly, the specimen is placed in the air to be weighed, then, the specimen is placed on a lifting appliance to be weighed in water, finally, the lifting appliance is placed in water alone to be weighed, a buoyancy of the specimen in water is obtained by calculation according to the three weighed values, the volume of the specimen is
calculated in combination with the water density, and the density of the alloy may be calculated according to the mass of the specimen in the air and the calculated volume, wherein the used specimen is the same as the specimen measured by XRD; and quasi-static tensile mechanical property test: an axial quasi-static tensile test at room temperature is performed by adopting a CMT4305 microcomputer electronic universal testing machine according to the standard GB/T228.1-2010, a strain rate is selected as 10^-3s^-1, and a test specimen is a non-standard I-shaped piece with the thickness of 1.0 mm, the width of 3.14 mm, the parallel segment length of 10 mm and the gauge length of 5 mm.

Embodiment 1

A lightweight high-entropy alloy Ti₆₀Zr₂₀V₃Nb₁₇ with high strength and high plasticity is prepared by the following steps:

step 1, elements Ti, Zr, V and Nb of which the purities are not smaller than 99.7wt% are adopted as raw materials, the raw materials are firstly polished by using a grinding wheel to remove oxide coatings on surfaces of the raw materials, and are then cleaned with anhydrous ethanol by ultrasonic oscillation, and clean raw materials with a total mass of (70±0.01) g are weighed according to an atomic percentage of Ti:Zr:V:Nb=60:20:3:17;
step 2, the weighed raw materials are sequentially placed in a water-cooled copper crucible of a high-vacuum non-consumable electric arc smelting furnace according to melting points from low to high, then, vacuumization is performed, and after the vacuum degree in the smelting furnace reaches 2.5×10^-3 Pa, and argon is filled as a protective gas; before the alloy is smelted, firstly, a pure metal titanium ingot is smelted to further reduce the content of oxygen in a furnace chamber of the smelting furnace, then, alloying smelting is performed, electromagnetic stirring is utilized for alloy homogenization during smelting, and an alloy liquid generated by smelting is cooled to obtain an alloy ingot; and the alloy ingot is overturned and is repeatedly smelted for four times to obtain a high-entropy alloy ingot; and step 3, the high-entropy alloy ingot is sealed in an argon-filled quartz tube to be subjected to solution treatment at the temperature of 900°C, and the temperature is kept for 1 h to obtain the high-entropy alloy Ti₆₀Zr₂₀V₃Nb₁₇.

It can be known from the XRD spectrum in Fig. 1 that the prepared high-entropy alloy Ti₆₀Zr₂₀V₃Nb₁₇ is mainly composed of a BCC phase. It can be known from a metallograph in Fig. 2 that the prepared high-entropy alloy Ti₆₀Zr₂₀V₃Nb₁₇ is of an equiaxed grain structure. It can be known from a test result in Fig. 8 that the prepared high-entropy alloy Ti₆₀Zr₂₀V₃Nb₁₇ has the yield strength of 758.06 MPa and the elongation at break of 18.11%. It can be known by test and calculation that the prepared high-entropy alloy Ti₆₀Zr₂₀V₃Nb₁₇ has the density of 5.8356 g/cm³.

Embodiment 2

A lightweight high-entropy alloy Ti₃₀Zr₂₇V₁₈Nb₂₅ with high strength and high plasticity is prepared by the following steps:

step 1, elements Ti, Zr, V and Nb of which the purities are not smaller than 99.7wt% are adopted as raw materials, the raw materials are firstly polished by using a grinding wheel to remove oxide coatings on surfaces of the raw materials, and are then cleaned with anhydrous ethanol by ultrasonic oscillation, and clean raw materials with a total mass of (70±0.01) g are weighed according to an atomic percentage of Ti:Zr:V:Nb=30:27: 18:25;
step 2, the weighed raw materials are sequentially placed in a water-cooled copper crucible of a high-vacuum non-consumable electric arc smelting furnace according to melting points from low to high, then, vacuumization is performed, and after the vacuum degree in the smelting furnace reaches 2.5×10^-3 Pa, and argon is filled as a protective gas; before the alloy is smelted, firstly, a pure metal titanium ingot is smelted to further reduce the content of oxygen in a furnace chamber of the smelting furnace, then, alloying smelting is performed, electromagnetic stirring is utilized for alloy homogenization during smelting, and an alloy liquid generated by smelting is cooled to obtain an alloy ingot; and the alloy ingot is overturned and is repeatedly smelted for four times to obtain a high-entropy alloy ingot; and
step 3, the high-entropy alloy ingot is sealed in an argon-filled quartz tube to be subjected to solution treatment at the temperature of 1200°C, and the temperature is kept for 1 h to obtain the high-entropy alloy Ti₃₀Zr₂₇V₁₈Nb₂₅.

It can be known from the XRD spectrum in Fig. 1 that the prepared high-entropy alloy Ti₃₀Zr₂₇V₁₈Nb₂₅ is mainly composed of a BCC phase. It can be Known from a metallograph in Fig. 3 that the prepared high-entropy alloy Ti₃₀Zr₂₇V₁₈Nb₂₅ is of an equiaxed grain structure. It can be known from a test result in Fig. 8 that the prepared high-entropy alloy Ti₃₀Zr₂₇V₁₈Nb₂₅ has the yield strength of 991.64 MPa and the elongation at break of 12.95%. It can be known by test and calculation that the prepared high-entropy alloy Ti₃₀Zr₂₇V₁₈Nb₂₅ has the density of 6.0938 g/cm³.

Embodiment 3

A lightweight high-entropy alloy Ti₅₀Zr₁₈V₁₂Nb₁₆Al₄ with high strength and high plasticity is prepared by the following steps:

step 1, elements Ti, Zr, V, Nb and Al of which the purities are not smaller than 99.7wt% are adopted as raw materials, the raw materials are firstly polished by using a grinding wheel to remove oxide coatings on surfaces of the raw materials, and are then cleaned with anhydrous ethanol by ultrasonic oscillation, and clean raw materials with a total mass of (70±0.01) g are weighed according to an atomic percentage of Ti:Zr:V:Nb:Al=50:18:12:16:4;
step 2, the weighed raw materials are sequentially placed in a water-cooled copper crucible of a high-vacuum non-consumable electric arc smelting furnace according to melting points from low to high, then, vacuumization is performed, and after the vacuum degree in the smelting furnace reaches 2.5×10^-3 Pa, and argon is filled as a protective gas; before the alloy is smelted, firstly, a pure metal titanium ingot is smelted to further reduce the content of oxygen in a furnace chamber of the smelting furnace, then, alloying smelting is performed, electromagnetic stirring is utilized for alloy homogenization during smelting, and an alloy liquid generated by smelting is cooled to obtain an alloy ingot; and the alloy ingot is overturned and is repeatedly smelted for four times to obtain a high-entropy alloy ingot; and
step 3, the high-entropy alloy ingot is sealed in an argon-filled quartz tube to be subjected to solution treatment at the temperature of 1000°C, and the temperature is kept for 3 h to obtain the high-entropy alloy Ti₅₀Zr₁₈V₁₂Nb₁₆Al₄.

It can be known from the XRD spectrum in Fig. 1 that the prepared high-entropy alloy Ti₅₀Zr₁₈V₁₂Nb₁₆Al₄ is mainly composed of a BCC phase. It can be known from a metallograph in Fig. 4 that the prepared high-entropy alloy Ti₅₀Zr₁₈V₁₂Nb₁₆Al₄ is of an equiaxed grain structure. It can be known from a test result in Fig. 8 that the prepared high-entropy alloy Ti₅₀Zr₁₈V₁₂Nb₁₆Al₄ has the yield strength of 795.2 MPa and the elongation at break of 36.57%. It can be known by test and calculation that the prepared high-entropy alloy Ti₅₀Zr₁₈V₁₂Nb₁₆Al₄ has the density of 5.6072 g/cm³.

Embodiment 4

A lightweight high-entropy alloy Ti₄₀Zr₂₃V₁₃Nb₁₉Al₅ with high strength and high plasticity is prepared by the following steps:

step 1, elements Ti, Zr, V, Nb and Al of which the purities are not smaller than 99.7wt% are adopted as raw materials, the raw materials are firstly polished by using a grinding wheel to remove oxide coatings on surfaces of the raw materials, and are then cleaned with anhydrous ethanol by ultrasonic oscillation, and clean raw materials with a total mass of (70±0.01) g are weighed according to an atomic percentage of Ti:Zr:V:Nb:Al=40:23:13:19:5;
step 2, the weighed raw materials are sequentially placed in a water-cooled copper crucible of a high-vacuum non-consumable electric arc smelting furnace according to melting points from low to high, then, vacuumization is performed, and after the vacuum degree in the smelting furnace reaches 2.5×10^-3 Pa, and argon is filled as a protective gas; before the alloy is smelted, firstly, a pure metal titanium ingot is smelted to further reduce the content of oxygen in a furnace chamber of the smelting furnace, then, alloying smelting is performed, electromagnetic stirring is utilized for alloy homogenization during smelting, and an alloy liquid generated by smelting is cooled to obtain an alloy ingot; and the alloy ingot is overturned and is repeatedly smelted for four times to obtain a high-entropy alloy ingot; and
step 3, the high-entropy alloy ingot is sealed in an argon-filled quartz tube to be subjected to solution treatment at the temperature of 1100°C, and the temperature is kept for 3 h to obtain the high-entropy alloy Ti₄₀Zr₂₃V₁₃Nb₁₉Al₅.

It can be known from the XRD spectrum in Fig. 1 that the prepared high-entropy alloy Ti₄₀Zr₂₃V₁₃Nb₁₉Al₅ is mainly composed of a BCC phase. It can be known from a metallograph in Fig. 5 that the prepared high-entropy alloy Ti₄₀Zr₂₃V₁₃Nb₁₉Al₅ is of an equiaxed grain structure. It can be known from a test result in Fig. 8 that the prepared high-entropy alloy Ti₄₀Zr₂₃V₁₃Nb₁₉Al₅ has the yield strength of 1077.3 MPa and the elongation at break of 25.84%. It can be known by test and calculation that the prepared high-entropy alloy Ti₄₀Zr₂₃Vi₃Nbi₉Al₅ has the density of 5.9201 g/cm³.

Embodiment 5

A lightweight high-entropy alloy Ti₃₀Zr₄₅Nb₇Al₈Hf₁₀ with high strength and high plasticity is prepared by the following steps:

step 1, elements Ti, Zr, Nb, Al and Hf of which the purities are not smaller than 99.7wt% are adopted as raw materials, the raw materials are firstly polished by using a grinding wheel to remove oxide coatings on surfaces of the raw materials, and are then cleaned with anhydrous ethanol by ultrasonic oscillation, and clean raw materials with a total mass of (70±0.01) g are weighed according to an atomic percentage of Ti:Zr:Nb:Al:Hf=30:45:7:8:10;
step 2, the weighed raw materials are sequentially placed in a water-cooled copper crucible of a high-vacuum non-consumable electric arc smelting furnace according to melting points from low to high, then, vacuumization is performed, and after the vacuum degree in the smelting furnace reaches 2.5×10^-3 Pa, and argon is filled as a protective gas; before the alloy is smelted, firstly, a pure metal titanium ingot is smelted to further reduce the content of oxygen in a furnace chamber of the smelting furnace, then, alloying smelting is performed, electromagnetic stirring is utilized for alloy homogenization during smelting, and an alloy liquid generated by smelting is cooled to obtain an alloy ingot; and the alloy ingot is overturned and is repeatedly smelted for four times to obtain a high-entropy alloy ingot; and
step 3, the high-entropy alloy ingot is sealed in an argon-filled quartz tube to be subjected to solution treatment at the temperature of 1200°C, and the temperature is kept for 12 h to obtain the high-entropy alloy Ti₃₀Zr₄₅Nb₇Al₈Hf₁₀.

It can be known from the XRD spectrum in Fig. 1 that the prepared high-entropy alloy Ti₃₀Zr₄₅Nb₇Al₈Hf₁₀ is mainly composed of a BCC phase. It can be known from a metallograph in Fig. 6 that the prepared high-entropy alloy Ti₃₀Zr₄₅Nb₇Al₈Hf₁₀ is of an equiaxed grain structure. It can be known from a test result in Fig. 8 that the prepared high-entropy alloy Ti₃₀Zr₄₅Nb₇Al₈Hf₁₀ has the yield strength of 710.59 MPa and the elongation at break of 12.35%. It can be known by test and calculation that the prepared high-entropy alloy Ti₃₀Zr₄₅Nb₇Al₈Hf₁₀ has the density of 6.4338 g/cm³.

Embodiment 6

A lightweight high-entropy alloy Ti₅₀Zr₂₅V₇Nb₁₂Al₅Fe₁ with high strength and high plasticity is prepared by the following steps:

step 1, elements Ti, Zr, V, Nb, Al and Fe of which the purities are not smaller than 99.7wt% are adopted as raw materials, the raw materials are firstly polished by using a grinding wheel to remove oxide coatings on surfaces of the raw materials, and are then cleaned with anhydrous ethanol by ultrasonic oscillation, and clean raw materials with a total mass of (70±0.01) g are weighed according to an atomic percentage of Ti:Zr:V:Nb:Al:Fe=50:25:7:12:5:1;
step 2, the weighed raw materials are sequentially placed in a water-cooled copper crucible of a high-vacuum non-consumable electric arc smelting furnace according to melting points from low to high, then, vacuumization is performed, and after the vacuum degree in the smelting furnace reaches 2.5×10^-3 Pa, and argon is filled as a protective gas; before the alloy is smelted, firstly, a pure metal titanium ingot is smelted to further reduce the content of oxygen in a furnace chamber of the smelting furnace, then, alloying smelting is performed, electromagnetic stirring is utilized for alloy homogenization during smelting, and an alloy liquid generated by smelting is cooled to obtain an alloy ingot; and the alloy ingot is overturned and is repeatedly smelted for four times to obtain a high-entropy alloy ingot; and
step 3, the high-entropy alloy ingot is sealed in an argon-filled quartz tube to be subjected to solution treatment at the temperature of 1000°C, and the temperature is kept for 12 h to obtain the high-entropy alloy Ti₅₀Zr₂₅V₇Nb₁₂Al₅Fe₁.

It can be known from the XRD spectrum in Fig. 1 that the prepared high-entropy alloy Ti₅₀Zr₂₅V₇Nb₁₂Al₅Fe₁ is mainly composed of a BCC phase. It can be known from a metallograph in Fig. 7 that the prepared high-entropy alloy Ti₅₀Zr₂₅V₇Nb₁₂Al₅Fe₁ is of an equiaxed grain structure. It can be known from a test result in Fig. 8 that the prepared high-entropy alloy Ti₅₀Zr₂₅V₇Nb₁₂Al₅Fe₁ has the yield strength of 995.49 MPa and the elongation at break of 9.45%. It can be known by test and calculation that the prepared high-entropy alloy Ti₅₀Zr₂₅V₇Nb₁₂Al₅Fe₁ has the density of 5.5533 g/cm³.

Claims

A lightweight high-entropy alloy with high strength and high plasticity, characterized in that the high-entropy alloy is marked as Ti_aZr_bV_cNb_dM_x according to an atomic number ratio, M is more than one of Al, Hf, Cr, Fe, Mg, Be, Li, Mo, Co, Ni, Si, B, O and N,
wherein 25<a≤65, 0<b≤55, 0≤c<25, 0<d≤35, 0≤x<20, a+b+c+d+x=100, and c and x cannot be 0 at the same time.
The lightweight high-entropy alloy with high strength and high plasticity according to claim 1, characterized in that in Ti_aZr_bV_cNb_dM_x, 25<a≤60, 15≤b≤50, 0≤c<25, 5≤d≤30, 0≤ x<20, a+b+c+d+x=100, and c and x cannot be 0 at the same time.
The lightweight high-entropy alloy with high strength and high plasticity according to claim 2, characterized in that M is more than one of Al, Hf, Cr, Fe, Mg, Be, Li, Mo, Co and Ni.
A preparation method of the lightweight high-entropy alloy with high strength and high plasticity according to any one of claims 1-3, characterized in that the method comprises the following steps:
step 1, placing clean elemental raw materials Ti, Zr, V, Nb and M into a smelting furnace of which the vacuum degree is smaller than or equal to 2.5×10^-3 Pa, and filling the smelting furnace with a protective gas; then, performing smelting, and cooling an alloy liquid generated by smelting to obtain an alloy ingot; and overturning the alloy ingot, and performing repeated smelting for more than three times to obtain a high-entropy alloy ingot; and

step 2, sealing the high-entropy alloy ingot in an argon-filled quartz tube, performing solution treatment at the temperature of 900-1200°C, and keeping the temperature for 1-12 h to obtain the high-entropy alloy.
The preparation method of the lightweight high-entropy alloy with high strength and high plasticity according to claim 4, characterized in that purities of the elemental raw materials Ti, Zr, V, Nb and M are respectively greater than or equal to 99.7wt%.
The preparation method of the lightweight high-entropy alloy with high strength and high plasticity according to claim 4, characterized in that an electric arc smelting furnace is selected for smelting.
The preparation method of the lightweight high-entropy alloy with high strength and high plasticity according to claim 4, characterized in that the protective gas is argon.