CN109328239B

CN109328239B - Magnesium alloy material and preparation method thereof

Info

Publication number: CN109328239B
Application number: CN201780038553.8A
Authority: CN
Inventors: 金相泫; 金载中; 权五德
Original assignee: Posco Co Ltd
Current assignee: Posco Holdings Inc
Priority date: 2016-06-23
Filing date: 2017-06-15
Publication date: 2021-05-11
Anticipated expiration: 2037-06-15
Also published as: EP3476959A1; KR101831385B1; WO2017222240A1; WO2017222240A8; KR20180000569A; US20190177819A1; CN109328239A; EP3476959B1; EP3476959A4; JP2019524988A; JP6799618B2

Abstract

The invention relates to a magnesium alloy material and a preparation method thereof. An exemplary embodiment of the present invention provides a magnesium alloy material including, with respect to a total of 100 wt%, 0.8 wt% to 1.8 wt% of Mn, 0.2 wt% or less (excluding 0%) of Ca, and the balance Mg and inevitable impurities, the magnesium alloy material having a recrystallized structure of 99 vol% or more with respect to 100 vol% of an entire microstructure of the magnesium alloy material.

Description

Magnesium alloy material and preparation method thereof

Technical Field

The invention relates to a magnesium alloy material and a preparation method thereof.

Background

Recently, as the LED industry is continuously developed, the development of high power LED lighting of several tens to several hundreds of watts is more and more active. Therefore, the heat sink for releasing heat generated from the LED becomes large in size and weight, and it becomes important to solve these problems. Since the weight of the heat dissipation member accounts for about 80% of the total weight of the LED lighting, the LED efficiency can be effectively improved by reducing the weight of the heat dissipation member. Therefore, it is actually necessary to reduce the weight of the heat sink.

Magnesium has been attracting attention as a relevant light metal. The density of magnesium is 1.74g/cm³Magnesium is classified as the lightest metal among structural metals including aluminum and steel. Further, pure magnesium has a thermal conductivity of about 155W/mK, which is considerably excellent in view of specific gravity. However, the thermal conductivity of the conventional magnesium alloy is about 80W/mK, which is lower than that of pure magnesium.

This is probably due to the alloy composition and the manufacturing process added for the purpose of improving mechanical strength. Because the solid solution rate of the added alloy components and internal substances or defects such as intermetallic compounds, dislocations, etc. impair the thermal conductivity.

Korean patent laid-open No. 1516378 discloses a method for manufacturing a high thermal conductivity magnesium alloy sheet. Although the above patent discloses a magnesium alloy excellent in thermal conductivity, a magnesium alloy sheet is disclosed, and therefore, further molding is required to be used as a heat radiating plate.

In addition, the magnesium alloy sheet has a thermal conductivity of about 120W/mK lower than that of pure magnesium (155W/mK), and thus is insufficient for replacing the existing material in the heat dissipation plate market.

Therefore, in an exemplary embodiment of the present invention, the microstructure of the magnesium alloy material may be controlled by removing unnecessary alloying elements and controlling the manufacturing process in various ways. Thus, a magnesium alloy material having more excellent thermal conductivity can be provided.

Disclosure of Invention

Technical problem

The invention provides a magnesium alloy material and a preparation method thereof.

Technical scheme

An exemplary embodiment of the present invention provides a magnesium alloy material including, with respect to a total of 100 wt%, 0.8 wt% to 1.8 wt% of Mn, 0.2 wt% or less (excluding 0%) of Ca, and the balance Mg and inevitable impurities, the magnesium alloy material having a recrystallized structure of 99 vol% or more with respect to 100 vol% of an entire microstructure of the magnesium alloy material.

The magnesium alloy material may have an average crystal grain diameter of 10 to 20 μm.

The magnesium alloy material may have a thermal conductivity of greater than or equal to 135W/mK.

A method of producing a magnesium alloy material according to another exemplary embodiment of the present invention may include: continuously casting the alloy melt into a blank for later use; a step of subjecting the billet to a homogenization heat treatment; preheating the blank after the homogenization heat treatment; a step of performing hot extrusion on the preheated blank to prepare an extruded material; and a step of heat-treating the extruded material thus produced.

The step of heat-treating the prepared extrudate may be heat-treated at a temperature ranging from 200 ℃ to 400 ℃. More specifically, the heat treatment may be performed for 0.5 hours to 2 hours.

The step of hot extruding the preheated billet to form an extruded material may be hot extruded in a direct extrusion manner.

The step of hot-extruding the preheated billet to form an extruded material may be hot-extruded at a temperature ranging from 350 ℃ to 550 ℃. More specifically, the hot extrusion may be performed at a speed of 10mpm to 30 mpm.

The step of preheating the homogenized blank may be carried out in an indirect heating type heating furnace. More specifically, it may be preheated to a temperature range of 350 ℃ to 550 ℃.

The step of subjecting the billet to the homogenization heat treatment may be performed at a temperature ranging from 400 ℃ to 500 ℃. More specifically, the homogenization heat treatment may be performed for 10 hours to 16 hours.

In the step of continuously casting an alloy melt into a billet for use, the alloy melt may contain 0.8 to 1.8 wt% of Mn, 0.2 wt% or less (excluding 0%) of Ca, and the balance of Mg and inevitable impurities, relative to 100 wt% of the total amount of the melt.

In addition, the step of continuously casting the alloy melt into a billet for standby may be performed at a temperature ranging from 650 ℃ to 750 ℃.

Furthermore, the alloy melt may be continuously cast at a speed ranging from 50mm/min to 150 mm/min.

The magnesium alloy material may have a recrystallized structure of 99 vol% or more with respect to 100 vol% of the entire microstructure of the magnesium alloy material.

Effects of the invention

According to an exemplary embodiment of the present invention, a high heat-dissipation magnesium alloy material excellent in thermal conductivity and a method for producing the same may be provided.

Drawings

Fig. 1 is a schematic view of a direct extrusion extruder used in a production method of a magnesium alloy material according to an exemplary embodiment of the present invention.

Fig. 2 shows the microstructure based on the heat treatment temperature after extrusion of the example and the microstructure based on the heat treatment temperature after rolling of the comparative example 1 observed with an optical microscope.

FIG. 3 is a view comparing surface characteristics of an extrudate based on the presence or absence of Ca component addition by examples of the present application and comparative example 5.

Detailed Description

The advantages, features and methods of accomplishing the same may be understood more clearly by reference to the drawings and the examples detailed below. However, the present invention can be embodied in various different forms and is not limited to the embodiments disclosed below. The following examples are put forth so as to provide those skilled in the art with a complete and complete understanding of the present invention, and are to be construed as being limited only by the scope of the appended claims. Like reference numerals refer to like elements throughout the specification.

Accordingly, in some embodiments, well-known techniques are not described in detail to avoid obscuring the present invention. Unless otherwise defined, all terms (including technical and scientific terms) used in this specification have the same meaning as commonly understood by one of ordinary skill in the art. In the following description, when a certain component is "included" in a certain portion, unless specifically stated to the contrary, the component further includes other components, and the other components are not excluded. The singular forms "a", "an" and "the" are intended to include the plural forms as well, unless expressly stated otherwise.

An exemplary embodiment of the present invention may provide a magnesium alloy material including 0.8 wt% to 1.8 wt% of Mn, 0.2 wt% or less (excluding 0%) of Ca, and the balance of Mg and inevitable impurities, with respect to 100 wt% of the total amount.

In this case, the magnesium alloy material may have a recrystallized structure of 99% by volume or more with respect to 100% by volume of the entire microstructure of the magnesium alloy material.

More specifically, the microstructure of the magnesium alloy material may be a completely recrystallized structure in which a deformed structure and a secondary phase are hardly present.

Further more specifically, as for the magnesium alloy material, a magnesium alloy material having a completely recrystallized structure as described above can be obtained by the following production method of a magnesium alloy material.

The average crystal grain diameter of the magnesium alloy material can be controlled as described above by the heat treatment step in the production method of the magnesium alloy material described below. When the average grain diameter of the magnesium alloy material is within the range, the thermal conductivity may be improved.

In the present specification, the grain size refers to the diameter of the crystal grain present in the measurement unit. If the crystal grains are non-spherical, the crystal grain diameter refers to a diameter calculated as the diameter of an approximate sphere of the non-spherical crystal grains.

The reason for limiting the composition and the range of the components of the alloy in the present invention will be explained below.

Manganese (Mn) may comprise 0.8 wt% to 1.8 wt%.

More specifically, if the content of manganese is less than 0.8 wt%, the strength of the magnesium alloy material may be too low. Conversely, if it exceeds 1.8% by weight, many secondary phases are generated, possibly resulting in a decrease in thermal conductivity.

The calcium (Ca) may comprise less than or equal to 0.2 wt% (except 0%).

More specifically, when a trace amount of calcium is added, the ignition temperature of the alloy itself will be increased, thereby functioning to suppress ignition. In addition, in the hot extrusion process, it can also play a role of preventing surface cracks. However, if the content of calcium is more than 0.2 wt%, secondary phases such as Mg may be formed₂Ca, etc. In addition, in terms of thermal conductivity, the smaller the amount of the alloying element added, the more advantageous. Therefore, if the maximum addition amount is set to the above range, a secondary phase is not formed, and a magnesium alloy material excellent in thermal conductivity can be produced.

Thus, the magnesium alloy material may have a thermal conductivity of 135W/mK or more. More specifically, it may be 135W/mK to 145W/mK.

A method of producing a magnesium alloy material according to another exemplary embodiment of the present invention may include: continuously casting the alloy melt into a blank for later use; a step of subjecting the billet to a homogenization heat treatment; preheating the blank after the homogenization heat treatment; a step of performing hot extrusion on the preheated blank to prepare an extruded material; and a step of heat-treating the extruded material after extrusion.

First, a step of continuously casting the alloy melt into a billet for use may be performed.

In the step of continuously casting the molten alloy into a billet for later use, the molten alloy may contain 0.8 to 1.8% of Mn, 0.2% or less (excluding 0%) of Ca, and the balance of Mg and inevitable impurities, relative to 100 wt% of the total amount of the molten alloy.

The reason for limiting the composition and the components of the alloy melt is the same as the reason for limiting the composition and the components of the magnesium alloy material, and therefore, the description thereof is omitted.

More specifically, the step of continuously casting the alloy melt into a billet for later use may be performed at a temperature ranging from 650 ℃ to 750 ℃.

The continuous casting speed may be 50mm/min to 150 mm/min.

In addition, continuous casting can be achieved by using a billet cutting device in conjunction with a casting speed, and defects inside and outside the billet can be minimized by employing an electromagnetic field processing method (EMC/EMS).

Then, a step of subjecting the blank to a homogenization heat treatment may be performed.

More specifically, the billet may be subjected to a homogenization heat treatment at a temperature ranging from 400 ℃ to 500 ℃.

Even more specifically, the billet may be subjected to a homogenization heat treatment for 10 hours to 16 hours.

If the temperature for the homogenization heat treatment of the billet is too low or the time is too short, the homogenization treatment of the nonuniform microstructure generated at the time of casting is not smoothly completed. Therefore, the pressing pressure may become high at the time of the subsequent pressing process. Conversely, if the temperature or time for homogenizing the blank is too high, localized melting may occur in some enrichment layers and segregation zones. This may cause defects in the blank.

Then, a step of preheating the homogenized blank may be performed.

The homogenized blank may be preheated in an indirect heating furnace.

More specifically, if the homogenized blank is preheated in a direct heating type heating furnace, local surfaces may be overheated due to direct flame. Thus, there is a risk that the surface melts to cause a fire. Therefore, the billet can be preheated in an indirect heating type heating furnace.

More specifically, the indirect heating type heating furnace may be, for example, an Induction heater (Induction heater) using a high-frequency or low-frequency Induction current, but is not limited thereto as long as a flame is not directly emitted as a torch (torch).

More specifically, the homogenized heat treated billet may be preheated to a temperature in the range of 350 ℃ to 550 ℃.

More specifically, if the billet after the homogenization heat treatment is preheated to a temperature lower than 350 ℃, the stress for plastically deforming the billet in the hot extrusion step described below may increase, and the extruder may be subjected to a large load due to the high extrusion pressure. Thus, the extrusion speed cannot be increased, and productivity is lowered.

On the contrary, if the billet after the homogenizing heat treatment is preheated to a temperature higher than 550 ℃, the extrusion speed is controlled to be increased at the time of extrusion in a hot extrusion step described below, and thus friction with an extrusion die and plastic deformation cause heat generation, possibly causing the surface temperature of the billet to exceed the solidus temperature of the material. As a result, defects may be generated on the surface of the billet due to the local melting. In addition, due to overheating, abnormal coarse grains may occur, which may cause surface defects.

By preheating the billet after the homogenization heat treatment for the time described above, it is possible to easily extrude without causing the extruder to bear a large load in the hot extrusion step described below and without generating surface defects.

Then, a step of hot-extruding the preheated billet to form an extruded material may be performed. More specifically, the hot extrusion can be rapidly performed before the preheated billet is cooled by the aforementioned step of preheating the billet after the homogenization heat treatment.

More specifically, the preheated billet may be hot extruded by direct extrusion. Still more specifically, hot extrusion may be performed using a direct extrusion extruder (as shown in fig. 1 of the present application).

Fig. 1 of the present application is a schematic view of a direct extrusion extruder used in a production method of a magnesium alloy material according to an exemplary embodiment of the present invention.

More specifically, the billet 11 loaded in the extrusion cylinder 31 is extruded from the die 21 by applying pressure to the ram 41 of the direct extrusion extruder to form the extruded material 12. Therefore, the extrusion material 12 may be directly extruded in the same direction as the advancing direction of the ram 41.

In this case, the mold 21 may use a mold designed to be adjustable in temperature according to seasons or extrusion conditions to minimize thermal deformation. Further, a multistage mold, a holder, and the like may be included.

The preheated billet may be hot extruded at a temperature ranging from 350 ℃ to 550 ℃.

More specifically, by hot-extruding the preheated billet in the temperature range, an extruded material can be easily produced without causing the extruder to bear a large load and without generating surface defects.

The preheated billet may be hot extruded at a speed of 10mpm to 30 mpm.

More specifically, if the hot extrusion speed is too slow, the productivity may be significantly reduced. Conversely, if the extrusion speed is too fast, the extrusion pressure becomes too high, and therefore the extruder may be subjected to overload. In addition, in some high temperature and high velocity zones, surface cracks may develop due to local melting.

Then, a step of heat-treating the produced extrudate may be included.

More specifically, in the step of heat-treating the extruded material produced, the extruded material may be heat-treated at a temperature ranging from 200 ℃ to 400 ℃.

More specifically, the extrudate may be heat-treated for 0.5 to 2 hours.

By subjecting the prepared extruded material to heat treatment in the temperature range and the time, the deformed texture and residual stress, etc. generated in the aforementioned hot extrusion step can be relieved. Thereby, a magnesium alloy material having a recrystallized structure of 99 vol% or more with respect to 100 vol% of the entire microstructure can be obtained. Therefore, the magnesium alloy material may have a thermal conductivity of 135W/mK or more.

The following examples are given for the purpose of illustration. However, the following examples are only for illustrating the present invention, and the contents of the present invention are not limited to the following examples.

Examples

Continuously casting an alloy melt into a billet for standby, wherein the alloy melt comprises 0.8 to 1.8 wt% of Mn, less than or equal to 0.2 wt% (except 0%) of Ca, and the balance of Mg and inevitable impurities relative to 100 wt% of the total.

The billet was then subjected to a homogenization heat treatment at 400 ℃ for 16 hours.

Then, the homogenized blank was preheated at a temperature of 430 ℃ for 4 hours.

And then, directly carrying out hot extrusion on the preheated blank by using a hot extrusion machine. At this time, hot extrusion was performed at 430 ℃ at a speed of 15mpm, thereby preparing an extruded material.

Then, the extruded material after extrusion is subjected to heat treatment at 300 ℃ for 1 hour, and finally the magnesium alloy material is obtained.

Comparative example 1

Strip casting (strip casting) of a magnesium alloy comprising, with respect to 100% by weight of the total, 0.5% to 2.0% of Mn, less than or equal to 0.1% (excluding 0%) of Al, 8ppm to 15ppm of Be, less than or equal to 0.2% (excluding 0%) of Ca, and the balance Mg, into a sheet ready for use.

Then, the plate was subjected to a homogenization heat treatment under the same conditions as in the examples of the present application.

And then, warm-rolling the homogenized plate at a temperature of 150-300 ℃.

Comparative example 2

A commercial AZ31 magnesium alloy was prepared.

Comparative example 3

A commercial AZ61 magnesium alloy was prepared.

Comparative example 4

Commercially available STS304 stainless steel was prepared.

Comparative example 5

Continuously casting an alloy melt into a billet for standby, wherein the alloy melt comprises 0.8-1.8 wt% of Mn, the balance of Mg and inevitable impurities relative to 100 wt% of the total. In comparison with the examples, the other components and compositions of the alloy melt were the same except that the Ca component was not contained.

Then, performing homogenization heat treatment on the blank; preheating the blank after the homogenization heat treatment; a step of performing hot extrusion on the preheated blank to prepare an extruded material; and the step of heat-treating the extruded material after extrusion was also carried out under the same conditions as in the examples, thereby producing a magnesium alloy material.

Experimental example: comparative experiment of thermal conductivity

Then, comparative experiments were performed on the thermal conductivities of the prepared examples and comparative examples 1 to 4. At this time, the test piece was processed into a disk shape having a diameter of 10mm to 13mm and a thickness of 2.0mm to 3.0mm, and the thermal conductivity was measured at 25 ℃ by a thermal parameter measuring apparatus, and the results thereof are shown in table 1 below.

[ TABLE 1 ]

No.	Thermal conductivity (W/mK, 25 ℃ C.)
		Examples	138.51
Comparative example 1	119.98
		Comparative example 2	86.92
Comparative example 3	65.63
		Comparative example 4	18.75

The comparison in table 1 above shows the thermal conductivity of the examples of the present application and the commercial alloys, i.e., comparative examples 1 to 4.

As a result, the thermal conductivity of the examples of the present application is significantly superior to that of the comparative examples 1 to 4.

More specifically, the comparative example 1 is a case where an alloy melt containing Mn, Al, Be, and Ca was strip-cast and then warm-rolled to form a magnesium alloy sheet. As shown in table 1 above, the thermal conductivity of the examples of the present application is superior to that of the comparative example 1, which can be explained by the microstructures of the examples and comparative example 1.

The microstructures of the examples and comparative example 1 are shown in fig. 2 of the present application.

More specifically, fig. 2 is a picture of observing a microstructure under a heat treatment condition according to an exemplary embodiment of the present invention with changing a temperature for the example made by extrusion and the comparative example 1 made by a strip casting method. In this case, the heat treatment was performed at each temperature for 1 hour.

As shown in fig. 2 of the present application, the comparative example 1 observed many deformed structures such as shear band (shear band), twinning (twin) defect, etc. due to plastic working. Moreover, the comparative example 1 also accumulated a lot of residual stress due to the accumulated pressure.

In contrast, some recrystallized structures were confirmed in the microstructures of the extruded materials prepared by the hot extrusion step of the examples (extruded state of the examples) of the present application, as if they were annealed. However, some twinned structures and secondary phases (black particles) were also confirmed, but the fraction of deformed structures was also confirmed to be far less than in the comparative example 1 with the naked eye. Therefore, in comparative example 1, which was prepared by strip casting and warm rolling, a large amount of deformed structure remained even if the subsequent heat treatment was performed at the same temperature and time as in the examples of the present application after rolling.

On the other hand, in the examples of the present application, the fractions of the internal stress, deformed structure, and quadratic phase, which are accumulated in the extruded material (extruded state of the example) prepared before the heat treatment, are significantly less than the fraction of the entire microstructure, and therefore, recovery and recrystallization are smoothly started by performing the subsequent heat treatment. As a result, the fraction of the recrystallized structure is 99 vol% or more with respect to 100 vol% of the entire microstructure.

Further, it was confirmed that the grain size of the crystal grains in the examples of the present application was relatively coarse. That is, the factors impairing the thermal conductivity in the microstructure of the example of the present application are significantly less than those of the microstructure of the comparative example 1.

From this, it was confirmed that, as shown in Table 1, the thermal conductivity of the comparative example 1 was about 120W/mK, while the thermal conductivity of the examples of the present application was about 20W/mK higher than that of the comparative example 1. The thermal conductivity of pure magnesium metal is about 155W/mK, and that of commercial magnesium alloy is about 80W/mK, which is very excellent compared to the thermal conductivity of the examples of the present application.

In the present application, unnecessary alloying elements are reduced, and process conditions are controlled in the production step of the magnesium alloy material, thereby obtaining a recrystallized microstructure with almost no residual stress, secondary phase, deformed structure, and the like, which results in the characteristics as described above. More specifically, a recrystallized structure of 99 vol% or more is formed with respect to 100 vol% of the entire microstructure, and as a result, the above-described characteristics are obtained.

In addition, fig. 3 of the present application is a view comparing surface characteristics of extruded materials based on the presence or absence of addition of Ca component by examples and comparative examples 5 of the present application.

Therefore, as shown in fig. 3 of the present application, with the present application example containing a Ca component, the ignition temperature of the alloy is increased because of containing a trace amount of the Ca component, so that surface cracks can be suppressed at the time of hot extrusion. This revealed that the resin had an excellent surface shape.

In contrast, for comparative example 5 containing no trace amount of Ca, surface cracks caused deterioration of the surface shape of the magnesium alloy at the time of hot extrusion because the ignition temperature was low. For this reason, it is important to add a trace amount of Ca in terms of productivity.

While the embodiments of the present invention have been described with reference to the drawings, it will be understood by those skilled in the art that the present invention can be embodied in other specific forms without changing the technical spirit or essential characteristics thereof.

Accordingly, the above embodiments are exemplary only and not limiting. The scope of the present invention is defined by the appended claims rather than the foregoing description, and all changes and modifications that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Description of the symbols

1: direct extrusion type extruding machine

11: blank material

12: extruded material

21: mold (Die, extrusion Die)

22: mold base (Die Holder, extrusion mold support)

31: extrusion container

41: indenter (Ram, part moved by hydraulic pressure)

Claims

1. A method for preparing a magnesium alloy material is characterized by comprising the following steps:

a step of continuously casting an alloy melt into a billet for later use, the alloy melt including 0.8 to 1.8 wt% of Mn, 0.2 wt% or less and more than 0 wt% of Ca, and the balance of Mg and inevitable impurities, with respect to 100 wt% of the total melt;

a step of subjecting the billet to a homogenization heat treatment;

preheating the blank after the homogenization heat treatment;

a step of performing hot extrusion on the preheated blank to prepare an extruded material; and

a step of heat-treating the produced extruded material,

wherein the step of heat-treating the extruded material is heat-treating at a temperature ranging from 200 ℃ to 400 ℃;

wherein, in the step of heat-treating the produced extruded material,

the heat treatment is carried out for 0.5 to 2 hours;

the magnesium alloy material has a recrystallized structure of 99 vol% or more with respect to 100 vol% of the entire microstructure of the magnesium alloy material.

2. The method for producing a magnesium alloy material according to claim 1, characterized in that:

and performing hot extrusion on the preheated blank to prepare an extruded material in a direct extrusion mode.

3. The method for producing a magnesium alloy material according to claim 2, characterized in that:

the step of hot-extruding the preheated billet to form an extruded material is to perform hot extrusion at a temperature ranging from 350 ℃ to 550 ℃.

4. The method for producing a magnesium alloy material according to claim 3, characterized in that:

the step of hot-extruding the preheated billet to form an extruded material is hot-extruded at a speed of 10 to 30 mpm.

5. The method for producing a magnesium alloy material according to claim 1, characterized in that:

the step of preheating the homogenized blank is preheating in an indirect heating furnace.

6. The method for producing a magnesium alloy material according to claim 5, characterized in that:

and preheating the blank subjected to the homogenization heat treatment to a temperature range of 350 ℃ to 550 ℃.

7. The method for producing a magnesium alloy material according to claim 1, characterized in that:

the step of subjecting the billet to a homogenization heat treatment is to perform a homogenization heat treatment at a temperature range of 400 ℃ to 500 ℃.

8. The method for producing a magnesium alloy material according to claim 7, characterized in that:

in the step of subjecting the blank to the homogenization heat treatment,

the homogenization heat treatment is carried out for 10 to 16 hours.

9. The method for producing a magnesium alloy material according to claim 1, characterized in that:

a step of continuously casting an alloy melt into a billet for later use, the alloy melt including 0.8 to 1.8 wt% of Mn, 0.2 wt% or less and more than 0 wt% of Ca, and the balance of Mg and inevitable impurities, with respect to 100 wt% of the total melt; continuous casting is carried out at a temperature ranging from 650 ℃ to 750 ℃.

10. The method for producing a magnesium alloy material according to claim 9, characterized in that:

a step of continuously casting an alloy melt into a billet for later use, the alloy melt including 0.8 to 1.8 wt% of Mn, 0.2 wt% or less and more than 0% of bio-Ca, and the balance of Mg and inevitable impurities, with respect to 100 wt% of the total melt; continuous casting is carried out at a speed ranging from 50mm/min to 150 mm/min.

11. The method for producing a magnesium alloy material according to any one of claims 1 to 10, characterized in that:

the magnesium alloy material has an average crystal grain diameter of 10 to 20 μm.

12. The method for producing a magnesium alloy material according to any one of claims 1 to 10, characterized in that:

the magnesium alloy material has a thermal conductivity of 135W/mK or more.