KR20160014130A - High entropy alloy having excellent strength and ductility - Google Patents

Abstract

The present invention provides a high entropy alloy with excellent strength and ductility. The alloy is shown by the following chemical formula 1. Chemical formula 1 is (M^2_aM^3_bM^4_c)_x(M^5_dM^6_e)_y(M^1 )_z (x+y+z=100%, a+b+c=100%, d+e=100%). In the chemical formula 1, M^2, M^3, and M^4 are different front transition metals selected from a group composed of Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Hf, Ta, W, and Re; and M^5 and M^6 are different rear transition metals selected by a group composed of Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au. M^1 is at least a metal selected from a group composed of Co, Nb, and Fe; and x, y, and z satisfies 40%<=x<=60% and 30%<=y<=50%.

Description

[0001] The present invention relates to a high entropy alloy having excellent strength and ductility,

The present invention relates to metal alloys and relates to high entropy alloys.

High entropy alloys are characterized by alloying 5 to 35 atomic% or more of each of 5 or more elements, and the unique characteristics of the individual elements are mixed to exhibit new properties. Unlike an intermetallic compound that is easily produced from a general multicomponent alloy, such a high entropy alloy forms a solid solution by virtue of a high mixed entropy, so that it exhibits excellent strength through solid solution strengthening and has excellent mechanical properties even in a high temperature environment .

However, such a high entropy alloy not only exhibits limited plasticity, but also has a disadvantage in that the plastic deformation section is not long and the yield strength is low.

A problem to be solved by the present invention is to provide a high entropy alloy having excellent strength and excellent flexibility.

According to one aspect of the present invention, there is provided an alloy, wherein the alloy is represented by the following general formula (1).

[Chemical Formula 1]

(M ² _a M ³ _b M ⁴ _c ) _x (M ⁵ _d M ⁶ _e ) _y (M ¹ ) _z (x + y + z = 100%, a + b + c = 100%, d + %)

Wherein M ² , M ³ and M ⁴ are different electric transition metals selected from the group consisting of Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Hf, Ta, deulyigo, M ⁵ and M ⁶ are Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, and deulyigo different late transition metal selected from the group consisting of Au, M ¹ is Co, Nb, and Fe, and x, y, and z satisfy 40%? X? 60% and 30%? Y? 50%.

(X = 40%, y = 30%, z = 30%), point II (x = 60%, y = 30%, z = 10% ), And a point III (x = 40%, y = 50%, z = 10%). In Formula 1, a, b, and c have the same value, and d and e may have the same value. Wherein M ² , M ³ , and M ⁴ are different transition metals selected from the group consisting of Ti, Zr, and Hf, and M ⁵ and M ⁶ are selected from the group consisting of Ni and Cu But may be other later transition metals.

The alloy may have a composition represented by the following formula (2).

(2)

M ² _? M ³ _? M ⁴ _? M ⁵ _? M ⁶ _? M ¹ _z (? +? +? +? +? + Z = 100%

In the above formula (2), the definition of M ¹ , M ² , M ³ , M ⁴ , M ⁵ and M ⁶ is the same as that of the above formula 1, z satisfies 10% ≦ z ≦ 30% ,?,?, and? may all have the same value.

The alloy may have a composition represented by the following formula (3).

(3)

Ti _α Zr _β Hf _γ Cu _δ Ni _ε M ¹ _z (α + β + γ + δ + ε + z = 100%)

In the above formula (3), z satisfies 10%? Z? 30%, and?,?,?,?, And? Can all have the same value.

The alloy may have a composition of Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Co ₁₇ , Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Nb ₁₇ , or Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Fe ₁₇ .

The alloy according to the embodiments of the present invention has high strength and good ductility, so that it is excellent in fracture resistance.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a graph showing the content relationship of metal elements contained in an alloy according to embodiments of the present invention. Fig.
2 to 8 are X-ray diffraction graphs (a) of specimens 1 to 7 and stress-strain curves (b) under compressive stress at room temperature.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Like reference numerals designate like elements throughout the specification.

The high entropy alloy according to an embodiment of the present invention may have a composition represented by the following formula (1).

[Chemical Formula 1]

(M ² _a M ³ _b M ⁴ _c ) _x (M ⁵ _d M ⁶ _e ) _y (M ¹ ) _z (x + y + z = 100%

Wherein M ² , M ³ and M ⁴ are different electric transition metals selected from the group consisting of Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Hf, Ta, M ⁵ and M ⁶ are different transition metals selected from the group consisting of Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, (Late Transition Metal), and M ¹ may be at least one metal selected from the group consisting of Co, Nb, and Fe. In this case, M ¹ , M ² , M ³ , M ⁴ , M ⁵ , and M ⁶ may be different metals.

At this time, M ² , M ³ , M ⁴ , M ⁵ , and M ⁶ , and additionally M ¹ , have a small atomic radius difference of 12% or less with each other and the mixing heat between them is -50 KJ / mol to 50 KJ / mol , A simple solid solution can be obtained. More specifically, M ² , M ³ , and M ⁴ can be different electro-transition metals selected from the group consisting of Ti, Zr, and Hf, and M ⁵ and M ⁶ are selected from the group consisting of Ni and Cu May be different late transition metals.

In the above formula (1), x, y and z may satisfy 40%? X? 60% and 30%? Y? 50%. (X = 40%, y = 30%, z = 30%), point II (x = 60%, y = 30%, z = 10% , And a point III (x = 40%, y = 50%, z = 10%). In the above formula (1), a + b + c may be 100%, and d + e may be 100%. In addition, a, b, and c may have substantially the same value, and specifically, a = b = c. Furthermore, d and e may also have substantially the same value, specifically d = e.

Such a high entropy alloy has a homogeneous composition with five or more metal elements and a disordered dense packing structure. Such a high entropy alloy has a higher strength than a polycrystalline alloy, can have excellent wear and corrosion resistance, and excellent ductility. As described above, the high entropy alloy according to the present embodiment has high strength and good ductility, so that it is excellent in fracture resistance. Therefore, such a high entropy alloy can be used as a heat resistant structural material. It has excellent mechanical properties even at high temperatures and is excellent in heat resistance and internal durability, and can be used in fields such as heat resistant structural materials such as automobile cylinders.

In one embodiment, the high entropy alloy may have a composition represented by the following formula (2).

(2)

M ² _? M ³ _? M ⁴ _? M ⁵ _? M ⁶ _? M ¹ _z (? +? +? +? +? + Z = 100%

In Formula 2, M ¹ , M ² , M ³ , M ⁴ , M ⁵ , and M ⁶ may be the same as in Formula 1. In the above formula (2), 10%? Z? 30% is satisfied, and?,?,?,?, And? Can all have the same value.

In this case, since five or more elements in the alloy are added at the same atomic ratio, the entropy becomes higher and the strength can be further improved.

In one embodiment, the high entropy alloy may have a composition represented by the following formula (3).

(3)

Ti _α Zr _β Hf _γ Cu _δ Ni _ε M ¹ _z (α + β + γ + δ + ε + z = 100%)

In the above formula (3), 10%? Z? 30% is satisfied, and?,?,?,?, And? Have the same value.

In an embodiment, the high entropy alloy has a composition of Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Co ₁₇ , Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Nb ₁₇ , or Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Fe ₁₇ Lt; / RTI &gt;

Such a high entropy alloy can be formed by quantifying an element having a purity of 99.9% or more to satisfy any one of the above formulas (1) to (3) and then using an arc melting method and an inhalation casting method in a high purity argon gas atmosphere. At this time, the specimen may be inverted by inverting the specimen five times or more to uniformize the microstructure.

Hereinafter, exemplary embodiments of the present invention will be described in order to facilitate understanding of the present invention. It should be understood, however, that the following examples are intended to aid in the understanding of the present invention and are not intended to limit the scope of the present invention.

&Lt; Example of alloy production &

Alloy Specimen Preparation Example 1: Preparation of Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Co ₁₇

Ti (purity> 99.995%), Zr (10 mm bulk form, purity> 99.7%), Hf (10 mm bulk form, purity> 99.95%), Ni (3 mm in diameter and 3 mm in thickness, (3 mm in diameter and 3 mm thick rod shape, purity > 99.99%), Cu (3 mm diameter and 3 mm thick rod shape, purity > 99.997%) and Co The amorphous alloy was quantified as a total amount of Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Co ₁₇ and alloyed by arc melting in a high purity Ar (99.99%) gas atmosphere. In order to prevent the reaction between the sample and impurities remaining in the chamber and the residual oxygen, a Ti getter was dissolved before dissolution of the alloying elements, and then a work was performed. In order to prevent the homogenization of the alloy and segregation, Shaped parent alloy was inverted and melted more than 5 times. Thereafter, the molten alloy in the molten state was sucked into the water-cooled copper mold using the difference in vacuum degree between the main chamber and the suction chamber, thereby preparing a rod-like specimen having a diameter of 2 mm and a length of 50 mm.

Alloy Specimen Preparation Example 2: Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Nb ₁₇

Ti, Zr, Hf, Ni, Cu, and Nb are used as the final amorphous alloy in the form of Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Nb ₁₇ (10 mm or less in plate form, purity> 99.95% , The rod-like specimen was prepared in the same manner as in Production Example 1, except that the total amount was quantified.

Alloy Specimen Preparation Example 3: Preparation of Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Fe ₁₇

Ti, Zr, Hf, Ni, Cu, and Fe are used as the final amorphous alloy in the form of Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Fe ₁₇ (bulk of less than 5 mm, purity> 99.9% , The rod-like specimen was prepared in the same manner as in Production Example 1, except that the total amount was quantified.

Alloy specimen Comparative Examples 1 to 4: Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Ag ₁₇

(10 mm or less in bulk form, purity > 99.99%) instead of Co, and the final amorphous alloy was Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Ag ₁₇ , Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Al ₁₇ , Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Sn ₁₇ , and Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Mo ₁₇ . The rod-shaped specimens were prepared in the same manner.

<Alloy specimen evaluation example: Mechanical characteristics analysis>

To evaluate the mechanical properties of the alloys specimens, the compressive strength was measured using a universal testing machine. Compressive strength measurements were carried out at equilibrium compressive stress at room temperature and at constant strain rate (strain rate = 1x10 ^-3 / s). The specimens for compression test were prepared as rod - like specimens of 2 mm in height and 4 mm in height, and were deformed until fracture of specimen occurred.

Table 1 below shows the composition and mechanical properties of the alloy specimens produced.

Furtherance σ _y (MPa) σ _max (MPa) 竜_p (%) Psalm 1 Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Co ₁₇ 2091.942 2209.268 2.283 Psalm 2 Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Nb ₁₇ 1635.183 2019.628 2.47 Psalm 3 Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Fe ₁₇ 2255.76 2353.159 1.5 Psalm 4 Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Ag ₁₇ 1137.352 1137.352 - Psalm 5 Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Al ₁₇ 949.68 1010.183 0.353 Psalm 6 Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Sn ₁₇ 1209.42 1390.20 0.44 Psalm 7 Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Mo ₁₇ 1242.62 1242.62 - σ _y (MPa): Stress at the beginning of specimen deformation
σ _max (MPa): Stress at the time of specimen failure
ε _p (%): degree of deformation

2 to 8 are X-ray diffraction graphs (a) of specimens 1 to 7 and stress-strain curves (b) under compressive stress at room temperature.

Referring to the stress-strain curves (b) of FIGS. 2 to 8 and Table 1 above, when M ¹ is Co, Nb, and Fe in Formulas 1 to 3 (ie, in the case of specimens 1 to 3) (Σ _y (MPa), σ _max (MPa)) as compared with the case where M ¹ is other metals, ie, Ag, Al, Sn, Mo (ie, in the case of specimens 4 to 7) , The plastic section (ε _p (%)) is increased and ductility is also improved.

Referring to the X-ray diffraction graphs (a) of FIGS. 2 to 8, it can be seen that only relatively simple peaks appear even though the specimens 1 to 7 are all alloys containing six metal elements. From these, it can be seen that the specimens 1 to 7 formed a simple solid solution.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, This is possible.

Claims (7)

1. An alloy having a composition represented by the following formula:
[Chemical Formula 1]
(M ² _a M ³ _b M ⁴ _c ) _x (M ⁵ _d M ⁶ _e ) _y (M ¹ ) _z (x + y + z = 100%, a + b + c = 100%, d + %)
In Formula 1,
M ² , M ³ and M ⁴ are different transition metals selected from the group consisting of Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Hf, Ta,
M ⁵ and M ⁶ are different late transition metals selected from the group consisting of Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt,
M ¹ is at least one metal selected from the group consisting of Co, Nb, and Fe,
x, y and z satisfy 40%? x? 60% and 30%? y? 50%. The method according to claim 1,
(X = 40%, y = 30%, z = 30%), point II (x = 60%, y = 30%, z = 10% ), And a point III (x = 40%, y = 50%, z = 10%). The method according to claim 1,
In formula (1), a, b, and c have the same value, and d and e have the same value. The method according to claim 1,
Wherein M ² , M ³ , and M ⁴ are different transition metals selected from the group consisting of Ti, Zr, and Hf, and M ⁵ and M ⁶ are selected from the group consisting of Ni and Cu Alloys that are other late transition metals. The method according to claim 1,
Wherein the alloy is an alloy having a composition represented by the following formula:
(2)
M ² _? M ³ _? M ⁴ _? M ⁵ _? M ⁶ _? M ¹ _z (? +? +? +? +? + Z = 100%
In Formula 2,
M ¹ , M ² , M ³ , M ⁴ , M ⁵ , and M ⁶ are the same as those in Formula 1,
z satisfies 10%? z? 30%
?,?,?,?, and? all have the same value. 6. The method according to claim 1 or 5,
Wherein the alloy is an alloy having a composition represented by the following Formula 3:
(3)
Ti _α Zr _β Hf _γ Cu _δ Ni _ε M ¹ _z (α + β + γ + δ + ε + z = 100%)
In Formula 3,
z satisfies 10%? z? 30%, and?,?,?,?, and? all have the same value. The method according to claim 6,
The alloy has a composition of Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Co ₁₇ , Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Nb ₁₇ , or Ti _16.6 Zr _16.6 Hf _16.6 Ni _16.6 Cu _16.6 Fe ₁₇ .

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