METHOD FOR FORMING AMORPHOUS ALLOY PART

Abstract

A method for forming an amorphous alloy part, including: placing a master alloy on a melting platform; heating and melting the master alloy under vacuum to yield an alloy melt; stopping heating and allowing the alloy melt to cool to a temperature between a glass transition temperature and a liquidus temperature thereof; and press-forming and cooling the alloy melt, to form the amorphous alloy part.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of International Patent Application No. PCT/CN2015/083961 with an international filing date of Jul. 14, 2015, designating the United States, now pending, and further claims foreign priority benefits to Chinese Patent Application No. 201410719338.2 filed Nov. 30, 2014. The contents of all of the aforementioned applications, including any intervening amendments thereto, are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to a method for forming an amorphous alloy part.

Description of the Related Art

Typically, there are two methods for preparing an amorphous alloy part: vacuum die-casting forming technique and alloy-shaping technique in the supercooled liquid region.

In the vacuum die-casting forming technique, the alloy melt is filled in a mold cavity under pressure, and cooled, to achieve filling and shaping at liquidus temperatures. However, pores having irregular shapes and sizes tend to form on the surface and in the core of the product, adversely affecting the product quality.

In the alloy-shaping technique, the amorphous alloy is heated to a temperature between the glass transition temperature (Tg) and the initial crystallization temperature (Tx), and is then shaped. The range of the shaping temperatures is narrow and difficult to maintain. In addition, the method involves amorphous base materials, which are difficult to manufacture.

SUMMARY OF THE INVENTION

In view of the above-described problems, it is one objective of the invention to provide a method for forming an amorphous alloy part. By using the method, the amorphous alloy can be precisely shaped under low pressure at the solidification temperature of the amorphous alloy melt. The method is efficient and cost-saving; the technical process is short; and the quality of the resultant products is high.

To achieve the above objective, in accordance with one embodiment of the invention, there is provided a method for forming an amorphous alloy part, comprising: 1) placing a master alloy on a melting platform; 2) heating and melting the master alloy under vacuum to yield an alloy melt; 3) stopping heating and allowing the alloy melt to cool to a temperature between a glass transition temperature and a liquidus temperature; 4) press-forming and cooling the alloy melt to form the amorphous alloy part.

In a class of this embodiment, the master alloy is capable of forming amorphous alloy when the master alloy has uniform composition. The master alloy is prepared by smelting or casting. The master alloy is in a regular shape of rod, plate, flake, or sphere. A weight of the master alloy is determined by a shape and a size of the amorphous alloy part.

In a class of this embodiment, the vacuum is at a pressure of between 1×10⁻⁶ and 1×10⁻¹ Pa.

In a class of this embodiment, the material of the melting platform does not react with the master alloy and has no influence on melting and solidification of the master alloy.

In a class of this embodiment, a heating mode of the master alloy is electric arc heating, induction heating, resistance heating, laser heating, plasma heating, infrared heating, or microwave heating.

In a class of this embodiment, in 4), a cooling rate is between 10⁻² and 10² K/min. The cooling of the alloy melt is performed via a cooling mold or a cooling melting platform to yield an amorphous structure.

The method for forming the amorphous alloy part is applicable to preparations of all amorphous alloy parts comprising Zirconium-based amorphous alloy, Titanium-based amorphous alloy, Iron-based amorphous alloy, Nickel-based amorphous alloy, Aluminum-based amorphous alloy, Magnesium-based amorphous alloy, Palladium-based amorphous alloy, Silver-based amorphous alloy, Gold-based amorphous alloy, Hafnium-based amorphous alloy, Calcium-based amorphous alloy, Platinum-based amorphous alloy, Copper-based amorphous alloy, Cobalt-based amorphous alloy, and rare-earth based amorphous alloy.

Advantages of the method for forming an amorphous alloy part according to embodiments of the invention are summarized as follows:

1. Following the melting of the master alloy, the amorphous alloy is precisely formed under low pressure at the solidification temperature range of the amorphous alloy melt, that is, between the liquidus temperature (Tl) and the glass transition temperature (Tg). Within the temperature range, the formed alloy melt has smooth surface, good deformation property, and small solidification and contraction coefficient. The prepared amorphous alloy part has accurate size, smooth surface, compact structure, and free of shrinkage hole.

2. The method is efficient and cost-saving, has short technical process, and the prepared products have high quality.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described hereinbelow with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of an apparatus used in a method for forming an amorphous alloy part in accordance with one embodiment of the invention;

FIG. 2 is a Titanium-based amorphous alloy part in Example 1;

FIG. 3 is a Zirconium-based amorphous alloy part in Example 2; and

FIG. 4 is an X-ray diffraction diagram of an amorphous alloy part.

In FIG. 1, the following reference numbers are used: 1. Melting platform; 2. Vacuum chamber; 3. Master alloy; 4. Mold; and 5. Heating unit.

DETAILED DESCRIPTION OF THE EMBODIMENTS

For further illustrating the invention, experiments detailing a method for forming an amorphous alloy part are described below. It should be noted that the following examples are intended to describe and not to limit the invention.

As shown in FIG. 1, a master alloy 3 having certain components and certain weight is placed on a melting platform 1. Air in the vacuum chamber 2 is exhausted, and the master alloy 3 is heated and melted using a heating unit 5 under vacuum to yield an alloy melt. Heating is stopped and the alloy melt is naturally cooled to a temperature between a glass transition temperature (Tg) and a liquidus temperature (Tl). The alloy melt is pressed using the mold 4 and cooled, to form the amorphous alloy part.

Example 1

The shaping process of amorphous alloy part in the example is as follows:

1. Composition of the master alloy (atomic percentage): 32.8% of Titanium, 30.2% of Zirconium, 5.3% of Nickel, 9% of Copper, and 22.7% of Beryllium.

2. Melting the master alloy: the material of the master alloy is prepared and is placed in a crucible. Air is exhausted to form a vacuum at a pressure of between 5×10⁻³ and 5×10⁻¹ Pa (or inert gas is filled in). The master alloy with uniform composition are prepared by induction melting or electric arc melting. The master alloy is casted to form regular master alloy ingot (in the shape of rod, plate, or flake, etc.)

3. Cutting the master alloy: the casted master alloy ingot is cut using cutting equipment according to the weight of required amorphous alloy part.

4. Shaping and processing amorphous alloy part: the cut master alloy is placed on a melting platform. Air in the vacuum chamber is exhausted to form a vacuum at a pressure of between 1×10⁻³ and 1×10⁻¹ Pa (or inert gas is filled in). The master alloy is heated and melted by induction heating (or other heating modes such as electric arc heating, laser heating, etc.) to yield an alloy melt. Heating is stopped and the alloy melt is freely cooled to a temperature which is 20° C. higher than the melting temperature (in the temperature range between a glass transition temperature (Tg) and a liquidus temperature (Tl) of the amorphous alloy). The alloy melt is pressed using the mold until the mold cannot further move to contact the melting platform (or a specialized shaping platform in which the alloy melt is poured following the melting). Meanwhile, the alloy melt is quickly cooled to form the amorphous alloy part as shown in FIG. 2; in the example, the quick cooling is performed using a cooling melting platform, and the cooling rate is 10⁻¹ K/min.

Example 2

The example follows a basic process in Example 1, except that composition of the master alloy (atomic percentage) is: 54.73% of Zirconium, 29.75% of Copper, 4.97% of Nickel, 9.95% of Aluminum, 0.1% of Silver, and 0.5% of Yttrium. The amorphous alloy part prepared in the example is shown in FIG. 3.

As shown in FIGS. 2-3, the amorphous alloy part prepared by the method has smooth surface and accurate size. Analyzed from the scanning electron microscope, the amorphous alloy part has compact structure and no shrinkage hole (as shown in FIG. 4).

The alloy used in the embodiments of the invention can be any amorphous alloy, such as Titanium-based amorphous alloy, Zirconium-based amorphous alloy, Iron-based amorphous alloy, Nickel-based amorphous alloy, Magnesium-based amorphous alloy, Palladium-based amorphous alloy, Silver-based amorphous alloy, Hafnium-based amorphous alloy, Platinum-based amorphous alloy, or other amorphous alloy component of other system.

Unless otherwise indicated, the numerical ranges involved in the invention include the end values. While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Claims

1. A method for forming an amorphous alloy part, the method comprising:

1) placing a master alloy on a melting platform;

2) heating and melting the master alloy under vacuum to yield an alloy melt;

3) stopping heating and allowing the alloy melt to cool to a temperature between a glass transition temperature and a liquidus temperature thereof; and

4) press-forming and cooling the alloy melt, to form the amorphous alloy part.

2. The method of claim 1, wherein the master alloy is prepared by smelting or casting; the master alloy is in a shape of rod, plate, flake, or sphere; and a weight of the master alloy is determined by a shape and a size of the amorphous alloy part.

3. The method of claim 1, wherein the vacuum is a pressure of between 1×10−6 and 1×10−1 Pa.

4. The method of claim 1, wherein the melting platform does not react with the master alloy and has no influence on melting and solidification of the master alloy.

5. The method of claim 1, wherein a heating mode of the master alloy is electric arc heating, induction heating, resistance heating, laser heating, plasma heating, infrared heating, or microwave heating.

6. The method of claim 1, wherein in 4), a cooling rate of the alloy melt is between 10−2 and 102 K/min.