JP2963225B2 - Manufacturing method of amorphous magnesium alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an amorphous magnesium alloy having excellent specific strength by solidification.

[0002]

2. Description of the Related Art Conventionally, an amorphous alloy has been manufactured to have a thickness of 10 to 30 .mu.m and a width of 100 mm by direct cooling of a liquid by a single roll device which provides a cooling rate of 10 @ ⁴ K / sec or more. As a method for producing a material having a larger area, there is a vapor deposition method, and a material having a thickness of several μm is produced. Thicker than thin amorphous materials made by these methods,
Material with bulk (referred to as "bulk material" in the present application)
As a method of producing the powder, a method of hardening a pulverized powder obtained by mechanically pulverizing a ribbon produced by a one-roll method, or a method of bombarding an amorphous powder by gas atomization has been used.

[0003]

Conventionally, in order to make an amorphous alloy into a bulk, an amorphous powder produced by atomization or the like has been solidified by means of a pressing mold such as extrusion or press. The conditions were severe and it was difficult to produce a bulk material having a 100% amorphous structure. Further, since extrusion or pressing must be performed at a temperature lower than the crystallization temperature, a large molding pressure is required, and the production cost is increased, which is not practical. Therefore, the present invention can obtain a material having a large specific strength, which is a characteristic of an amorphous magnesium alloy, as a bulk material relatively easily and at low cost.
It is an object of the present invention to provide a method for making amorphous magnesium alloys of various different shapes.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a magnesium amorphous solidified material is cooled by cooling to a predetermined temperature in a magnesium alloy molten metal supply channel, and then introduced into a mold for performing a second stage cooling and then solidified. It is a method of manufacturing. The magnesium alloy of the present invention has a Mg _a M _b Al _c X _d
Y _e (wherein; M is La, Ce, Mm (misch metal), one or more elements consisting of Y, X is N
i, one or more elements of Cu, Z is one or more of Mn, Zn, Zr, Ti;
a is 70 to 90 at%, b is 2 to 15 at%, c is 1 to
9 at%, d is 2 to 15 at%, e is 0.1 to 8 at%
).

First, the composition of the magnesium alloy according to the present invention will be described. Mg is a base metal and a base metal necessary for weight reduction, M is an element essential for amorphousization of Mg, and Al is a strong oxide film to prevent magnesium from burning. It is an unavoidable element. X is also an essential component for making Mg amorphous. M is 15a
If it exceeds t%, the compound is precipitated, and if it is less than 2 at%, it is difficult to make the compound amorphous. Further, if the content of Al is less than 1 at%, the effect of preventing fire is small. X is determined by the relationship with the M element, but if it is 2 at% or more, it is easy to be amorphous, and if it exceeds 15 at%, it becomes a brittle amorphous structure.

[0006] Zr and Ti provide heat resistance, but 8a
If the amount exceeds t%, amorphousization is inhibited. Also, Zn, Mn
Has the effect of improving the strength, and is in the same component range as Zr from the relationship of the solid solution range. In the present invention, the magnesium alloy has a glass transition temperature (Tg) and a glass transition temperature (Tg) and its crystallization temperature (Tx) in order to form a thick amorphous alloy even in a casting with a slow cooling rate. Is required to be 10K or more (see FIG. 1). In FIG. 1, the right side of the curves indicated by A and B is a crystal formation region. As shown in the figure, when ΔK> 10K, the crystal formation region moves to a longer time side.

[0007] In addition, the casting method of the present invention, the molten metal 10 ²
A flow path for cooling at a cooling rate Vc of K / sec or more.
In the first cooling zone, the molten metal is melted at the melting temperature of the alloy having the above composition.
After cooling to the vicinity, the molten metal is at least 1-5 thick.
mm in a mold with a cavity,
In the second cooling zone consisting of the mold, the molten metal
First stage cooling rate V up to glass transition temperature (Tg)
Cooling faster than c, then continuing to cool further
Produces amorphous magnesium alloy with thickness of 1-5mm
How to As shown in FIG. 2, the first-stage cooling in the vicinity of the melting temperature is performed at a rate at which partial crystallization occurs when cooling to Tg at the cooling rate. By performing a two-stage cooling process that performs a second-stage cooling at a higher cooling rate than the first-stage cooling following the first-stage cooling, the amorphous magnesium having a relatively large wall thickness while avoiding passage through the crystal formation region. An alloy casting can be obtained.

If the amount of heat taken from the molten metal in the first-stage cooling is increased (see the dashed line in FIG. 2), it is possible to avoid passing through the crystal formation region, but such a cooling rate is difficult to realize by casting. It is. In order to reduce the burden of cooling for amorphization in the second cooling, the cooling rate of the first cooling is preferably 10 ² K / sec or more.
It is preferable to flow the magnesium alloy from the molten metal reservoir into a flow path having a narrowed path in the form of an orifice or a nozzle, and to perform the first-stage cooling so that the temperature of the molten metal flowing out of the flow path is close to the melting temperature. In this case, the first stage cooling rate> 10 ² K / sec
Can be easily achieved. Subsequently, in the second stage cooling, sufficient cooling is performed by bringing the molten metal into close contact with the cooling mold to improve heat conduction.

It is desirable that a mold made of a mold or other material having good heat conductivity be cooled with water. A high cooling rate can be obtained by pressure casting or preferably centrifugal casting with a gravitational acceleration of 50 G or more in the second stage cooling of the magnesium alloy melt that has been sufficiently supercooled in the first stage. The bulk material that can be produced by the method of the present invention has a thickness of 1 to 5 mm. By changing the shape of the mold, amorphous magnesium alloys having various shapes can be manufactured. Such a bulk material can be used as a reinforcing material for a composite material with an aluminum alloy.

[0010]

In the present invention, the role of the first-stage cooling zone is to reduce the load of heat to be radiated when cooling in the second-stage cooling zone. Can be supplied to the zone.

Hereinafter, description will be made with reference to the drawings. 2 is a first-stage cooling zone, and 2-3 are second-stage cooling zones. The reason why the temperature gradient can be increased in the second-stage cooling zone is that the first-stage cooling zone takes away a part of the heat to be radiated from the molten metal.

Since the amount of heat to be dissipated in the second cooling zone can be reduced, the cooling rate in the second cooling zone is increased, and cooling can be performed without the occurrence of nose causing crystallization. As a result, even a thick material can be made amorphous. Note that, in the first-stage cooling zone, as much as possible below the Tm, i.e., it is desirable to reduce to Tm ₂ vicinity of Figure 2, the cooling of the second stage quench zone starting from the temperature indicated by Tm ₁ for heat dissipation capacity is small thin May be done.
Graph AB in FIG. 2 is a schematic diagram of the cooling rate when there is no first-stage cooling zone.

When the volume of the cast product is large, the heat release rate of the mold usually decreases with the passage of time after casting, so that the crystallization is affected by the nose (N) as shown in the figure. Is shown. As an example, Tm (Tm
₁ , Tm ₂ ) ± 20K. In the second stage cooling, cooling is performed in the mold so as not to cross the nose. A casting of an amorphous Mg alloy can be produced by the two-stage cooling method as described above. Hereinafter, the present invention will be described with reference to examples.

[0014]

【Example】

Example 1 In this example, an amorphous magnesium alloy having a composition of Mg ₇₉ Ni ₁₀ Y ₅ Al ₅ Zn _{1 and} a thickness of 2 mm, a width of 30 mm and a length of 30 mm was prepared. The casting apparatus is a mold casting apparatus shown in FIG. In the figure, 1 is a crucible for melting and pressurizing, 2 is a heater coil, 3 is a pool for guiding a plunger 4, 5
Is a nozzle, 6 is a mold, 7 is a die cavity, and 10 is a molten magnesium alloy.

The entire apparatus is in a box so that a vacuum atmosphere and an inert atmosphere can be freely created. After each magnesium alloy raw material was weighed, it was put into a crucible 1 made of calcia and melted by a high frequency using a heater coil 2.
A gas is introduced into the magnesium alloy melt 10 maintained at a temperature 100 ° C. higher than the melting point of the alloy by a nozzle opened at the top of the crucible, and the melt 10 is pressurized at 0.5 kg / cm ² to form a pool. Hot water was introduced into the mold 3, and then pressurized at 300 kg / cm ² by the plunger 4 and introduced into the die cavity 7 of the mold 6. The length of the nozzle 5 was 10 mm, which was designed to be longer than that of a normal die casting (length: 5 mm) to increase the temperature drop. From the result of temperature measurement by a thermocouple inserted into the mold 6, it was found that the molten magnesium alloy in the nozzle 5 had almost the melting point. Therefore, the first stage cooling was completed at the outlet of the nozzle 5. Thereafter, the molten metal was solidified in a mold as a second-stage cooling unit, and heat exchange with the mold was continued.
After cooling sufficiently, the product was taken out of the mold. When a mineral oil or the like was applied thinly to the mold as a mold wash, the product was easily taken out. When a sample was cut out from the product and the structure was examined, an X-ray diffraction pattern of a halo pattern peculiar to amorphous was obtained. The strength was equivalent to that of the ribbon material when compared by hardness.

Example 2 Each element was set in a melting part crucible in FIG. 4 so as to have a composition of Mg ₈₅ Ni ₅ La ₅ Al ₄ Zr ₁ . The molten metal flows out of the nozzle at a temperature 100 ° C higher than the melting point,
Pouring into a mold 102 with a diameter of 102 mm rotating at 300 rpm,
A cylindrical material having a cross section of 2 mm × 2 mm and a center diameter of 100 mm was prepared.

Example 3 The alloys shown in Tables 1 and 2 were cast by the method of Example 2, and the vitrification temperature (Tg) and the crystallization temperature (Tx) were measured. -Tg) value. Since the cast product of the comparative example was crystallized, a ribbon was made by a single roll method that can provide a cooling rate of 10 ⁵ K / sec or more, and Tg and Tx were measured. As a result, it can be seen that when the value of Tx−Tg = ΔT is 10K or more, the casting has an amorphous structure.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

[0021]

[Table] 4

[0022]

According to the present invention, since an amorphous magnesium alloy bulk material can be obtained by casting, a material excellent in strength and weight can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a continuous cooling curve.

FIG. 2 is an explanatory diagram of a continuous cooling curve illustrating two-stage cooling.

FIG. 3 is a view of a casting machine having a pressing device.

FIG. 4 is a view of a casting machine having a centrifugal casting device.

[Description of sign]

 Reference Signs List 1 crucible 2 heater coil 3 pool 4 plunger 5 nozzle 6 mold 10 molten magnesium alloy

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C22C 45/00 C22C 45/00 (72) Inventor Akihisa Inoue No. Address, Kawauchi, Aoba-ku, Sendai City, Miyagi Prefecture 11-806 (72) Inventor Akira Kato 2-36-1 Yagiyama Honcho, Taihaku-ku, Sendai City, Miyagi Prefecture Success 26 B101 (72) Inventor Toshiba Shibata 1-12-12 Yonegabukuro, Aoba-ku, Aoba-ku, Sendai City, Miyagi Prefecture (72) Inventor Hitoshi Yamaguchi 1-9-9 Yaesu, Chuo-ku, Tokyo Imperial Piston Ring Co., Ltd. (56) References JP-A-3-10041 (JP, A) JP-A-1-233048 (JP, A) JP-A-3-3 253525 (JP, A) JP-A-6-25805 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C22C 1/00-1/02 B22D 21/04

Claims (5)

(57) [Claims] 1. A method according to claim 1, wherein M _a M _b Al _c X _{d Ze} (wherein M is La, Ce, Mm
(Misch metal), Y is one or more elements of the (yttrium), X is Ni, one of Cu or two
A species of elements, Z is a Mn, Zn, Zr, Ti one or two or more, a is 70~90at%, b is 2~15at
%, C is 1 to 9 at%, d is 2 to 15 at%, e is 0.1 to 8 a
The molten metal having a composition of t% and a difference between glass transition temperature (Tg) and crystallization temperature (Tx) (T = Tx-Tg> 10K) is cooled at a cooling rate Vc of 10 ² K / sec or more. Channel
At the first stage cooling zone consisting, after cooling to <br/> melting temperature near the alloy having the composition, at least the thickness of the solution water
Is supplied into a mold having a cavity of 1 to 5 mm, and then, in a second-stage cooling zone composed of the mold , the molten metal is supplied.
Up to the glass transition temperature (Tg) of the alloy having the above composition
Cooling at a higher speed than the step cooling speed Vc , and then further cooling
To produce an amorphous magnesium alloy having a thickness of 1 to 5 mm by continuing the above . Here, Vc is a cooling rate at which partial crystallization occurs when cooling to the vitrification transition temperature at Vc. 2. The method for producing an amorphous magnesium alloy according to claim 1, wherein the molten metal flow path for performing the first stage cooling has a nozzle shape and is provided immediately before the mold. 3. The plunger according to claim 1, wherein the molten metal passage for performing the first stage cooling is a plunger.
2. The method for producing an amorphous magnesium alloy according to claim 1, wherein the amorphous magnesium alloy has a nozzle shape through which a molten metal flows under pressure and is provided immediately before a mold. 4. The method for producing an amorphous magnesium alloy according to claim 1, wherein the mold is rotated at a high speed, and a centrifugal force at a gravitational acceleration speed of 50 G or more is applied to the molten metal to pressurize the molten metal. 5. The Z component is one of Mn, Zr and Ti.
5. The method according to claim 1, wherein at least two kinds are provided. 6.
For producing an amorphous magnesium alloy.