WO2022065536A1

WO2022065536A1 - Lightweight multi-component alloy comprising aluminum and transition metal and production method therefor

Info

Publication number: WO2022065536A1
Application number: PCT/KR2020/012830
Authority: WO
Inventors: 모리시타유토; 황선태
Original assignee: 엘지전자 주식회사
Priority date: 2020-09-23
Filing date: 2020-09-23
Publication date: 2022-03-31

Abstract

A multi-component alloy of the present invention has a chemical composition comprising: 50 atom% to 55 atom% of aluminum (A); 12 atom% to 25 atom% of at least two kinds of elements selected from manganese (Mn), iron (Fe), cobalt (Co), and nickel (Ni); and the balance being impurities. The multi-component alloy has a Vickers hardness of 550 HV to 700 HV and a density of less than 5.5 g/cc.

Description

Lightweight polyvalent alloy containing aluminum and transition metal and method for manufacturing the same

The embodiment is applied to an automobile member, an electronic component, a building material, and the like, and relates to a light-weight polyvalent alloy containing aluminum and a transition metal having light weight and strength, and a method for manufacturing the same.

Metal materials are used in various automobile parts, mechanical parts, building materials, etc., and are used according to their mechanical properties and uses.

Steel materials have excellent mechanical properties, and they are often used for mechanical parts that require high hardness due to high wear, such as molds and bearings. In addition, in the case of insufficient hardness due to severe wear and tear on the surface of mechanical parts, the surface hardness is improved by subjecting the steel material to additional surface treatment such as induction hardening, nitriding treatment, plating, etc., thereby extending the life of the parts. However, various surface treatments are complicated and require delicate process management.

In addition, since the steel material is a material containing iron as a main component, it is dense and heavy. In recent years, as lightweight metal materials considering the global environment, aluminum alloys, magnesium alloys, etc. are often used as substitute materials for steel materials, but their use is limited because of insufficient hardness compared to steel materials.

Accordingly, there is a demand for a lightweight metal material having a hardness equal to or higher than that of a steel material and requiring no surface treatment process.

On the other hand, recently, a new alloy design concept called a high entropy alloy (hereafter, HEA) has been proposed. Unlike conventional alloys in which trace elements are added to a single main element, it is a multi-component alloy characterized by forming a single-phase solid solution with five or more main element elements, and it is a completely new alloy design concept that has not been considered until now.

HEA is defined as an alloy in which five or more kinds of main component elements are each composed of 5 atomic% to 35 atomic%. Moreover, when the mixing entropy ΔS calculated from the alloy composition shown in the following formula is 1.5R or more, it is classified as HEA.

[ceremony]

(R is the gas constant, N is the number of elements, and ci is the atomic ratio of component i.)

In addition, when ΔS is 1.0R or more and 1.5R or less, it is classified as a medium entropy alloy (MEA), and when it is 1.0R or less, it is classified as a low entropy alloy (LEA). When the number of elements increases with respect to the alloy composition and the atomic ratio of each element is large, the mixing entropy becomes a high value. Existing alloys, for example, steel materials, aluminum alloys, magnesium alloys, etc. often contain trace elements added to a single metal element, and most of the alloys fall under LEA.

A major feature of HEA or MEA is that elements with different atomic sizes are irregularly arranged in the crystal structure, so it is believed to have an effect of increasing strength and hardness due to large lattice strain. In addition, since it is an alloy system with many main constituent elements, the mixed entropy term in the Gibbs free energy equation takes a large value, and it is considered to have an effect of generating a solid solution because of its excellent chemical stability.

Accordingly, HEA is currently being actively researched as a structural material or aircraft material requiring high strength.

However, HEA and MEA reported at the present time are mainly composed of 3d transition metal elements. Therefore, the density of the alloy exceeds 7 g/cc, and the density is high and heavy. Low-density and light HEA or MEA have not been reported at this time.

JP2002-173732 (Patent Document 1) contains 5 to 11 main metallic elements, these main metallic elements contain titanium, vanadium, iron, nickel, copper, aluminum, molybdenum, zirconium, cobalt, HEA is disclosed which is composed of at least one element selected from the group consisting of chromium and palladium, while the number of moles of each major metal element is 5% to 30% of the total number of moles of the alloy.

However, as can be seen from the Examples, almost all of the constituent elements are occupied by 3d transition metal elements, all of which have a density of 5.5 g/cc or more.

JP2011-32514 (Patent Document 2) discloses a surface treatment method in which a nitrogen-containing compound layer with a Vickers hardness of 550 HV or higher, obtained after forming a chemical conversion film on a nitrogen compound layer formed through nitriding treatment of a steel material, and then uniformly remaining after high frequency heating is starting As can be seen from the examples, in this surface treatment method, after forming the nitrogen compound layer by salt bath softening treatment, chemical conversion treatment of the nitrogen compound layer with a chemical treatment solution, and then heating with high frequency quenching equipment for 0.3 seconds to less than 5 seconds After reaching 750 ° C to 860 ° C by the

JP2017-8357 (Patent Document 3) discloses a method for surface treatment of a nickel plating film having a Vickers hardness of 500 HV to 900 HV.

WO01/018273 (Patent Document 4) discloses a rolling bearing with high wear resistance in which a Vickers hardness of 720 HV or more is obtained through quenching and forging of a steel material.

All of the above Patent Documents 2 to 4 are surface treatment methods for steel materials, but since surface treatment is required to improve the surface hardness of the base material, all processes are cumbersome, and delicate process management is required. In addition, since the base material is a material containing iron as a main component, it has a high density and is heavy.

Steel materials have excellent mechanical properties and are often used for mechanical parts such as molds and bearings that require hardness. However, since the surface treatment process for increasing the lifespan of parts requires cumbersome or delicate management as in the above patent document, the surface treatment process is unnecessary and a material having high hardness is required.

In addition, since a steel material has a high density and a large weight, in recent years, a light alloy such as a magnesium alloy, an aluminum alloy, or a titanium alloy is attracting attention as a lightweight alloy material in consideration of the global environment. These lightweight alloys have a low density compared to steel materials, so they are lightweight, but they have insufficient hardness compared to steel materials, so their range of use is limited, and they are not a material that can replace steel materials. Therefore, a lightweight material having a hardness equal to or higher than that of a steel material subjected to surface treatment is required.

In the multi-component alloy of the present invention, aluminum (Al) is 50 atomic% to 55 atomic%, manganese (Mn), iron (Fe), cobalt (Co), and nickel (Ni) at least two elements selected from 12 atomic% to 25 atomic %, the balance has a chemical composition composed of impurities, the Vickers hardness is 550 HV or more to 700 HV or less, and the density of the alloy is less than 5.5 g/cc.

The alloy of the present invention is a multi-component alloy having a smaller density and lighter weight than a steel material, and having hardness equal to or greater than that of a steel material. In particular, it has a very high hardness equivalent to that of a material subjected to surface treatment of a steel material. Therefore, there is no need to perform a separate surface treatment process for the alloy of the present invention. Accordingly, the multi-component alloy of the present invention may be lightweight and high in hardness with sufficient potential to become a base material to be a substitute material for a steel material requiring surface treatment.

1 is a view showing the results of X-ray diffraction analysis according to Example 9.

In the present invention, aluminum is 50 atomic% to 55 atomic%, manganese (Mn), iron (Fe), cobalt (Co), and two or more elements selected from nickel (Ni) are 12 to 25 atomic%, the balance is inevitable It has a chemical composition composed of impurities, whereby it is possible to provide a light-weight and high-hardness multi-component alloy. The reason that the composition range is limited is that a composition outside the composition range has a low Vickers hardness and cannot achieve sufficient hardness.

When higher hardness is required, aluminum is 50 atomic% to 55 atomic%, manganese (Mn), iron (Fe), cobalt (Co), and nickel (Ni) 12 to 17 atomic% of three or more elements selected from the group consisting of It is more preferable to have a chemical composition composed of atomic % and the remainder of unavoidable impurities.

When higher hardness is required, aluminum is 50 to 55 atomic %, manganese (Mn), iron (Fe), cobalt (Co) and nickel (Ni) are 12 to 13 atomic %, and the balance is unavoidable. It is desirable to have a chemical composition composed of impurities.

It is unclear at present why the alloy of the present invention has a hardness equal to or greater than that of steel materials, but according to a recent study by HEA, if elements with different atomic sizes are irregularly arranged in the crystal structure in a multi-component alloy, large lattice deformation occurs. It is believed to be effective in increasing hardness.

Accordingly, in the alloy of the present invention, the mixing entropy calculated from the alloy composition is 1.0R or more and 1.5R or less, which corresponds to MEA, but hardness may be increased by the same effect as HEA.

The multi-component alloy of the present invention may be prepared by synthesis through heating. In the embodiment described below, the raw material is melted through an infrared heating furnace, but the embodiment is not limited thereto, and equipment such as a vacuum melting furnace and a high frequency melting furnace may be used as the melting equipment. In addition, synthesis through powder sintering is possible, and hot press, metal injection molding equipment (MIM), hot isostatic pressure equipment (HIP), additive molding equipment (AM), etc. can be used.

The multi-component alloy of the present invention prepared as described above may be applied to components of a compressor.

Hereinafter, the present invention will be described in more detail through multi-component alloys according to Examples and Comparative Examples. These manufacturing examples are merely presented as examples in order to explain the present invention in more detail. Therefore, the present invention is not limited to these preparation examples.

Example 1

Aluminum powder, manganese powder, and nickel powder, which are raw material powders of each element, were prepared as metal powders, and these powders were weighed in a total of 10 g in the following composition ratio.

Composition ratio (at%): 50 Al-25 Mn-25 Ni

Next, the weighed powder was mixed in a mortar, put in a MgO crucible, and heated in an infrared heating furnace to obtain an ingot through solidification in the crucible. The heating conditions at this time were a temperature increase rate of 50°C/min, a temperature of 1400°C, and a holding time of 10 minutes in an argon gas flow atmosphere.

Next, this sintered body was polished with a polishing paper of #400 to #2000 with a polishing machine, and buff-polished with an alumina polishing liquid as a final finishing polishing to obtain a surface with a metallic luster. The Vickers hardness was measured at 10 points on this metallic luster surface with a Vickers hardness meter, the average value of the Vickers hardness was measured, and the calculated density obtained by calculating the density of the alloy from atomic percent was measured.

Example 2

Composition ratio (at%): 50 After preparing a sintered body in the same manner as in Example 1, except that Al-25 Mn-25 Fe was used, Vickers hardness and calculated density were measured.

Example 3

Composition ratio (at%): 50 After preparing a sintered body in the same manner as in Example 1, except that Al-16 Mn-17 Fe-17 Ni was used, Vickers hardness and calculated density were measured.

Example 4

Composition ratio (at%): 55 After preparing a sintered body in the same manner as in Example 1, except that Al-20 Co-25 Ni was used, Vickers hardness and calculated density were measured.

Example 5

Composition ratio (at%): 50 After preparing a sintered body in the same manner as in Example 1, except that Al-25 Fe-25 Ni was used, Vickers hardness and calculated density were measured.

Example 6

Composition ratio (at%): 53 After preparing a sintered body in the same manner as in Example 1, except that Al-24 Mn-23 Co was used, Vickers hardness and calculated density were measured.

Example 7

Composition ratio (at%): 52 After preparing a sintered body in the same manner as in Example 1, except that Al-24 Co-24 Fe was used, Vickers hardness and calculated density were measured.

Example 8

Composition ratio (at%): 50 After preparing a sintered body in the same manner as in Example 1, except that Al-17 Mn-16 Co-17 Ni was used, Vickers hardness and calculated density were measured.

Example 9

Composition ratio (at%): 50 After preparing a sintered body in the same manner as in Example 1, except that Al-12 Mn-13 Fe-12 Co-12 Ni was used, Vickers hardness and calculated density were measured.

Example 10

Composition ratio (at%): 52 After producing a sintered body in the same manner as in Example 1 except that Al-16 Fe-16 Co-16 Ni was used, Vickers hardness and calculated density were measured.

Example 11

Composition ratio (at%): 51 After preparing a sintered body in the same manner as in Example 1, except that Al-17 Mn-16 Fe-16 Co was used, Vickers hardness and calculated density were measured.

Comparative Example 1

As metal powder, aluminum powder and nickel powder, which are raw material powders of each element, were prepared, and 10 g of these powders were weighed in total at the following composition ratios.

Composition ratio (at%): 50 Al-50 Ni

Next, the weighed powder was mixed in a mortar, put in a MgO crucible, and heated in an infrared heating furnace to obtain an ingot through solidification in the crucible. The heating conditions at this time were an argon gas flow atmosphere, a temperature increase rate of 50°C/min, a temperature of 1600°C, and a holding time of 10 minutes.

Next, this sintered compact was polished with a polishing paper of #400 to #2000 with a polishing machine, and buff-polished with an alumina polishing liquid as a final finishing polishing to obtain a metallic luster surface. The Vickers hardness was measured at 10 points on this metallic luster surface with a Vickers hardness meter, the average value of the Vickers hardness was measured, and the calculated density calculated from the atomic percent density of the alloy was measured.

Comparative Example 2

Composition ratio (at%): 45 After preparing a sintered body in the same manner as in Comparative Example 1 except that Al-40 Fe-15 Ni was used, Vickers hardness and calculated density were measured.

Comparative Example 3

Composition ratio (at%): 70 After preparing a sintered body in the same manner as in Comparative Example 1, except that Al-10 Co-20 Ni was used, Vickers hardness and calculated density were measured.

Referring to Table 1, it can be seen that the sintered body according to Comparative Examples has lower hardness than the sintered body according to Examples.

1 is a measurement result using an X-ray diffraction apparatus according to Example 9 and powder diffraction data of AlNi. As can be seen from Figure 1, Example 9 has the same crystal structure as the AlNi alloy, while it can be seen that the single-phase structure.

The alloy of the present invention was subjected to crystal structure analysis through an X-ray diffraction apparatus for all alloys of Examples 1 to 11, and it was confirmed that all of them had a single-phase structure. In the multi-component alloy of the present invention, elements having different atomic sizes are arranged in one crystal structure, and the hardness of the alloy may be increased due to the large crystal deformation.

Claims

Aluminum (Al) is 50 atomic% to 55 atomic%, manganese (Mn), iron (Fe), cobalt (Co), and two or more kinds of elements selected from nickel (Ni) are 12 to 25 atomic%, the balance is having a chemical composition consisting of impurities,

Vickers hardness is 550 HV or more and 700 HV or less,

A multi-component alloy with an alloy density of less than 5.5 g/cc.
The method of claim 1,

Aluminum (Al) is 50 atomic % to 55 atomic %, manganese (Mn), iron (Fe), cobalt (Co), and nickel (Ni) 12 atomic % to 17 atomic % of three or more elements selected from nickel (Ni), the remainder being impurities A multi-component alloy having a chemical composition consisting of
The method of claim 1,

Aluminum (Al) has a chemical composition of 50 atomic% to 55 atomic%, manganese (Mn), iron (Fe), cobalt (Co) and nickel (Ni) 12 to 13 atomic%, the balance being impurities plural alloys.
A method for producing the multi-component alloy of any one of claims 1 to 3, comprising:

A method for producing a multi-component alloy comprising a synthesis step of mixing the raw materials of the alloy and then heating and synthesizing.
As a product of the multi-component alloy prepared according to claim 4,

The product is a product of a multi-component alloy that is a component of a compressor.
A compressor having a built-in component of the compressor, which is a product of the multi-component alloy according to claim 5.