WO2015180616A1

WO2015180616A1 - Al-mg alloy plate, method of preparing the same and use thereof

Info

Publication number: WO2015180616A1
Application number: PCT/CN2015/079764
Authority: WO
Inventors: Faliang Zhang; Yongxi Jian; Qing Gong
Original assignee: Byd Company Limited
Priority date: 2014-05-27
Filing date: 2015-05-26
Publication date: 2015-12-03
Also published as: CN105331864A

Abstract

An Al-Mg alloy plate and a method for preparing the same are provided. The Al-Mg alloy plate having a thickness of larger than 5mm includes a crystalline grain having a crystal grain size of less than about 60 μm; a pore having a particle diameter of less than about 200 μm; and an impurity having a particle diameter of less than about 200 μm.

Description

AL-MG ALLOY PLATE, METHOD OF PREPARING THE SAME AND USE THEREOF

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to, and benefits of Chinese Patent Application No.201410226533.1, filed with the State Intellectual Property Office of P.R.C. on May 27, 2014, the entire content of which is incorporated herein by reference.

FIELD

Exemplary embodiments of the present disclosure relate generally to an Al-Mg alloy plate, a method of preparing the same and use of the Al-Mg alloy plate in preparing an electronic product.

BACKGROUND

Magnesium (hereinafter, magnesium may be referred to as “Mg” ) has significant features such as light weight to be used in all of the engineering metals, and small density of 1.78 g/cm³, which is about 2/9 of that of steel and 2/3 of that of aluminum (hereinafter, aluminum may be referred to as “Al” ) , and Mg is the lightest metal material with an engineering application value at present. In addition, a magnesium alloy has a relative high specific strength, a relative high specific stiffness, a better earthquake resistant performance and a higher resistance to radiation. As electronic products become thinner and lighter and functions thereof become more and more diverse, an Al-Mg alloy with a high strength and high heat conductivity becomes an important candidate structure material.

Though a magnesium ingot has a serious surplus production, the price thereof is relative low, even lower than that of an aluminum ingot, the cost of preparing and using an alloy plate especially a thin alloy plate is very high mainly for the following two reasons. On the one hand, the magnesium alloy has a close-packed hexagonal structure, a small slip system, and a poor plasticity at normal temperature, and therefore a multipass hot rolling is required when preparing a magnesium alloy plate, which may be prone to crack to cut down the production efficiency and yield, and the obtained plate may be thinner, the cost may be even ten times of that of an Al-Mg alloy plate. On the other hand, a slip system of a magnesium alloy is low at room temperature, and hard to cold deform, but it is possible to perform a process of heat deformation at a high temperature, in addition, and as for a complex precision mechanism, a process of deformation may be hard to perform. High cost and hard manufacture of a magnesium alloy may lead to a serious constraint to application of a magnesium alloy in electronics.

Though the magnesium alloy has a low cost, it is hard to apply the magnesium alloy in a product workpiece with a high requirement. Though a conventional die-casting may have some advantages such as high molding efficiency, mature technology and may be applied directly for the production of a workpiece with a thin wall, the mechanical property of products is low, which may not meet the usage requirement of moving parts. In addition, the magnesium alloy may be used for preparing an ingot thick plate with a relative low cost, but the obtained plate may still have big crystalline grain and some casting defects, thereby being difficult to get a magnesium alloy having high strength, high tenacity and a stable processing efficiency.

SUMMARY

Embodiments of the present disclosure seek to solve at least one of the problems, and to provide an Al-Mg alloy plate having a low cost, a good heat conductivity and a high mechanical property.

The inventor of the present disclosure has found that, with an Al-Mg alloy plate having a crystalline grain with a particle diameter of less than 60 μm, a pore with a particle diameter of less than about 200 μm and an impurity with a particle diameter of less than about 200 μm, the heat conductivity and mechanical property of the Al-Mg alloy plate may be improved, and then the obtained electronic products may have an improved heat conductivity and mechanical property, and have a stable and uniform appearance.

In order to achieve the above purpose, according to a first aspect of the present disclosure, an Al-Mg alloy plate is provided. The Al-Mg alloy plate having a thickness of larger than 5mm includes: a crystalline grain having a crystal grain size of less than about 60 μm； a pore having a particle diameter of less than about 200 μm； and an impurity having a particle diameter of less than about 200 μm.

According to a second aspect of the present disclosure, a method of preparing an Al-Mg alloy plate is provided. The method of preparing the Al-Mg alloy plate comprises the following steps: casting a raw material of the Al-Mg alloy plate at a temperature of 650℃ to 780℃ to obtain a cast bar； and extruding the cast bar at a temperature of 380℃ to 480℃, with an extrusion ratio of 5: 1 to 20: 1, and an extrusion speed of 0.5 m/min to 3 m/min to obtain the Al-Mg alloy plate.

According to a third aspect of the present disclosure, an Al-Mg alloy plate prepared by the above method is provided.

According to a fourth aspect of the present disclosure, use of the Al-Mg alloy plate in preparing an electronic product is provided.

According to a fifth aspect of the present disclosure, an electronic product comprising the Al-Mg alloy plate according to the first aspect and the third aspect of the present disclosure is provided.

According to a sixth aspect of the present disclosure, a method for preparing an electronic product is provided. The method comprises: providing the Al-Mg alloy plate according to the first aspect and the third aspect of the present disclosure； and optionally forming the electronic product.

In some embodiments of the present disclosure, the Al-Mg alloy plate has a heat conductivity coefficient larger than 80 w/m·K. In the Al-Mg alloy plate according to some embodiments of the present disclosure, a crystalline grain has a particle diameter of less than about 60 μm, a pore has a particle diameter of less than about 200 μm, an impurity has a particle diameter of less than 200 μm, and the yield may reach 94％ or more, such that the heat conductivity and mechanical property of the Al-Mg alloy plate may be improved, and the obtained electronic products may have an improved heat conductivity and mechanical property, and a stable and uniform appearance.

Additional aspects and advantages of embodiments of present disclosure will be given in part in the following descriptions, become apparent in part from the following descriptions, or be learned from the practice of the embodiments of the present disclosure.

DETAILED DESCRIPTION

Reference will be made in detail to embodiments of the present disclosure. The embodiments described herein with reference to drawings are explanatory, illustrative, and used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure.

In some embodiments of the present disclosure, an Al-Mg alloy plate is provided. In the Al-Mg alloy plate, a crystalline grain has a particle diameter of less than about 60 μm, a pore has a particle diameter of less than about 200 μm, an impurity has a particle diameter of less than 200 μm, and the Al-Mg alloy plate has a thickness of less than 5 mm.

Both heat conductivity and mechanical property of the Al-Mg alloy plate may be improved provided that, the crystalline grain of the Al-Mg alloy plate has a particle diameter of less than 60 μm, the pore has a particle diameter of less than about 200 μm, the impurity has a particle diameter of less than 200 μm, and the Al-Mg alloy plate has a thickness of less than 5 mm. In order to further improve heat conductivity and mechanical property of the Al-Mg alloy plate, in some embodiments, the crystalline grain of the Al-Mg alloy plate has a particle diameter of less than 30 μm.

In some embodiments of the present disclosure, in order to further improve heat conductivity and mechanical property of the Al-Mg alloy plate, both the pore and the impurity have a particle diameter less than 100 μm.

In some embodiments of the present disclosure, in order to further improve heat conductivity and mechanical property of the Al-Mg alloy plate, the Al-Mg alloy plate has a thickness of 5 mm to 25 mm.

In some embodiments of the present disclosure, the Al-Mg alloy plate comprises Mg, Zn, Al, Mn and M, in which M is selected from silicon and/or beryllium.

In some embodiments of the present disclosure, based on the total weight of the Al-Mg alloy plate, the Al-Mg alloy plate comprises: 84 wt％to 96.9 wt％of Mg, 0.5 wt％to 4 wt％of Zn, 0.5 wt％to 4 wt％of Al, 0.1 wt％to 2 wt％of Mn, 0 to 2 wt％of M, and a balance of the impurity.

In some embodiments of the present disclosure, when M comprises silicon and beryllium, and with a weight ratio of silicon to beryllium of 10: 1 to 1: 50, both heat conductivity and mechanical property of the Al-Mg alloy plate may be improved.

In some embodiments of the present disclosure, in order to improve heat conductivity and mechanical property of the Al-Mg alloy plate, the Al-Mg alloy plate has a heat conductivity coefficient larger than 80 w/m·K, alternatively larger than 100 w/m·K.

According to a second aspect of the present disclosure, a method of preparing Al-Mg alloy plate is provided, comprising steps of: casting a raw material of the Al-Mg alloy plate at a temperature in a range of 650℃ to 780℃ to obtain a cast bar, and extruding the cast bar at a temperature of 380℃ to 480℃, with an extrusion ratio of 5: 1 to 20: 1, and an extrusion speed of 0.5 m/min to 3 m/min to obtain the Al-Mg alloy plate.

The inventors of the present disclosure have found that conditions of casting and extruding may influence the particle diameters of the pore, the impurity and the crystalline grain, and the thickness of the Al-Mg alloy plate. Casting a raw material of the Al-Mg alloy plate is carried out at a temperature in a range of 650℃ to 780℃, extruding is carried out at a temperature of 380℃ to 480℃, with a extrusion ratio of 5: 1 to 20: 1, and a extrusion speed of 0.5 m/min to 3 m/min, so as to control both particle diameters of the pore and impurity to be less than 200 μm, the particle diameter of the crystalline grain to be less than 60 μm, and the thickness of the Al-Mg alloy plate to be larger than 5mm, thus improving heat conductivity and mechanical property of the Al-Mg alloy plate.

In some embodiments of the present disclosure, the casting method comprises semi-continuous casting method, thus further improving heat conductivity and mechanical property of the Al-Mg alloy plate.

In some embodiments of the present disclosure, the casting method may be any conventional casting method in the art, but, in order to further improve heat conductivity and mechanical property of the Al-Mg alloy plate, the casting comprises semi-continuous casting.

In some embodiments of the present disclosure, the casting is carried out as follows: the raw material of the Al-Mg alloy plate was semi-continuously cast at a temperature of 650℃ to 780℃. The semi-continuous casting method was carried out under the condition of: a diameter of a cast bar of 180 mm to 250 mm, a drawing speed of 20 cm/min, in a protection of inert gas and sulfur hexafluoride (SF6) . A covering agent was added uniformly in the whole process of fusion to avoid burning and the content of the covering agent may be 0.3 w％to 0.5 wt％of the weight of the deformed magnesium alloy. In addition, a fine turning was carried out on the surface of the cast bar, and treatment such as cutting was carried out on the head and tail of the cast bar.

In one embodiment of the present disclosure, extruding is performed as follows: according to requirement of extruding, the magnesium alloy cast bar was homogenizing annealed at a temperature of 300℃ to 400℃ for 3 h to 4 h, the extruding mold was heated up to a temperature of 380℃ to 450℃, and the extruding temperature was controlled in a range of 380℃ to 480℃ with an extrusion ratio of 5: 1 to 20: 1 at an extrusion speed of 0.5 m/min to 3 m/min, thus obtaining an Al-Mg alloy plate having a heat conductivity larger than 100 w/m·k and a thickness in the range of 5 mm to 25 mm. Therefore, both the particle diameters of the pore and the impurity of the obtained alloy plate were smaller than 150μm, and the particle diameter of the crystalline grain of the obtained alloy plate was 56μm. In the present disclosure, the extrusion ratio refers to a ratio of an input area to an output area.

In some embodiments of the present disclosure, the method of preparing the Al-Mg alloy plate further comprises rolling the Al-Mg alloy plate after extruding the cast bar, in which the rolling was carried out under conventional conditions, for example, a temperature of rolling was 350℃ to 450℃, the Al-Mg alloy plate after rolling has a thickness of 5 mm to 25 mm, and the heat conductivity of the Al-Mg alloy plate was larger than 100 w/m·k, both particle diameters of the pore and the impurity of the Al-Mg alloy plate were smaller than 100μm, and the particle diameter of the crystalline grain of the obtained alloy plate was smaller than 30μm.

In some embodiments of the present disclosure, the raw material of the Al-Mg alloy plate comprises Mg, Zn, Al, Mn and M, in which M is selected from silicon and/or beryllium, and based on the weight of the Al-Mg alloy plate, the Al-Mg alloy plate comprises: 84 wt％to 96.9 wt％of Mg, 0.5 wt％to 4 wt％of Zn, 0.5 wt％to 4 wt％of Al, 0.1 wt％to 2 wt％of Mn, 0 to 2 wt％of M, and a balance of the impurity. Since the raw material of the Al-Mg alloy plate contains the above components, it is possible to further enhance the heat conductivity and mechanical strength of the Al-Mg alloy plate. The components of the raw material of the Al-Mg alloy plate may also be conventional ones, such as AZ31, AZ91, etc.

When the raw material of the Al-Mg alloy plate contains the above components, preferably, when M consists of silicon and beryllium and a ratio of silicon to beryllium is 10: 1 to 1: 50, both heat conductivity and mechanical strength may be further improved.

In some embodiments of the present disclosure, the particle diameters of the pore and the impurity may be tested by an inspection technique, the particle diameter of the crystalline grain may be tested according to ASTM E112-95 standard, and the heat conductivity coefficient may be tested according to ASTM E1461-07 standard.

In some embodiments of the present disclosure, the impurity of the Al-Mg alloy plate mainly includes oxides, such as magnesium oxide, aluminium oxide and manganese oxide. The elementary substances of the raw material of the Al-Mg alloy plate may be inevitably oxidized into oxides. The impurity of the Al-Mg alloy plate may include non-molten materials and other doped impurities of the raw material of the Al-Mg alloy plate with a high melting point. Regardless of the kind of the impurity of the Al-Mg alloy plate, both particle diameters of the pore and the impurity may be tested by an inspection technique.

In a third aspect of the present disclosure, an Al-Mg alloy plate prepared by the method according to embodiments of the present disclosure may be provided.

In a fourth aspect of the present disclosure, use of the Al-Mg alloy plate according to embodiments of the present disclosure in preparing an electronic product is provided.

According to the use of the Al-Mg alloy plate according to embodiments of the present disclosure, the Al-Mg alloy plate may be manufactured into various electronic products by a common processing technique. In order to obtain an electronic product with a better heat-conducting property, stronger mechanical strength and a more stable appearance, preferably, the Al-Mg alloy plate may be numerical control manufactured and/or forging manufactured to form an electronic product, further preferably, the Al-Mg alloy plate may be forging manufactured and then numerical control manufactured.

In some embodiments of the present disclosure, the Al-Mg alloy plate was forging manufactured, polished, and then numerical control manufactured.

In some embodiments of the present disclosure, the process of the numerical control manufacturing includes at least one of turning, grinding, milling, drilling, and tapping, thus improving the thermal conductivity and mechanical strength of the electronic product, and improving the stability and the uniformity of the appearance of the product.

In some embodiments of the present disclosure, the forging manufacturing is carried out at a temperature in the range of 200℃ to 500℃, thus improving the thermal conductivity and mechanical strength of the electronic product, and improving the stability and the uniformity of the appearance of the product.

In a fifth aspect of the present disclosure, an electronic product comprising the Al-Mg alloy plate according to the first aspect and the third aspect of the present disclosure is provided.

In a sixth aspect of the present disclosure, a method for preparing an electronic product is provided. The method comprises: providing the Al-Mg alloy plate according to the first aspect and the third aspect of the present disclosure； and optionally forming the electronic product.

The present disclosure will be further described in details in conjunction with the detailed examples. It should be understood that the detailed examples below are only used to explain instead of limiting the present disclosure.

In the following Examples and Comparative Examples, the particle diameters of the pore and the impurity may be tested by an inspection technique, the particle diameter of the crystalline grain may be tested according to ASTM E112-95 standard, and the heat conductivity coefficient may be tested according to ASTM E1461-07 standard. The weight falling test was performed under the conditions as follows: the dropping height was 1.5m, and the balance weight was 500g. The extrusion ratio refers to a ratio of an input area to an output area.

Example 1

In this example, an Al-Mg alloy plate of the present disclosure, a method of preparing the same and use thereof were provided.

A raw material of the Al-Mg alloy plate was compounded according to AZ31 alloy. A semi-continuous casting of the raw material was carried out at a temperature of 700℃, with a diameter of the cast bar of 210mm, a drawing speed of 20 cm/min, and in an atmosphere of Ar and SF₆. RJ-6 (covering agent) was added uniformly in the whole process to avoid burning, and the content of the covering agent was 0.3 weight parts. An elaborate turning was carried out on the surface of the cast bar and a treatment was carried out on the head and tail of the cast bar, then an inspection was carried out on the cast bar, to obtain an Al-Mg alloy plate having a pore with a particle diameter of less than 200μm and an impurity with a particle diameter of less than 200μm. A treatment was carried out on the head and tail of the cast bar to remove the head and tail of the cast bar.

The cast bar was annealed uniformly at a temperature of 300℃ for 3 hours, the extrusion die was preheated to 380℃, and the extrusion temperature was controlled to be 420℃, with an extrusion ratio of 15: 1 and an extrusion speed of 1 m/min, to obtain an Al-Mg alloy plate with a thickness of 5 mm, and a heat conductivity coefficient of 80 w/m·K. The particle diameter of a pore of the Al-Mg alloy plate was 150μm, the particle diameter of an impurity of the Al-Mg alloy plate was 150μm, and the particle diameter of a crystalline grain of the Al-Mg alloy plate was 55μm. A plate including a pore and an impurity with particle diameters of larger than 150μm may be treated as a defective product.

The above plate was rolled at a temperature of 400℃ for 10 times to obtain a plate with a thickness of 5 mm. The plate includes a pore and an impurity with particle diameters of less than 100μm, and a crystalline grain with a particle diameter of 29μm.

Then, the plate was forged with a forging machine at a temperature of 200℃ and polished to obtain a workblank having a surface with a roughness of less than 10μm. The workblank was numerical control manufactured with a numerical control machine tool to obtain a final product with a heat conductivity coefficient of 80 w/m·K. The particle diameter of a pore of the final product was less than 100μm, the particle diameter of an impurity of the final product was less than 100μm, and the particle diameter of a crystalline grain of the final product was 29μm. The yield was 95％after forging and numerical controlling, and when 100 products were processed, 5 products have tiny cracks caused by forging, and a weight falling test was carried out on the rest 95 products without any crack.

Example 2

Based on 100 weight parts of a raw material of the Al-Mg alloy plate, the content of Mg thereof was 94 weight parts, the content of Zn thereof was 2 weight parts, the content of Al thereof was 2 weight parts, the content of Mn thereof was 1.5 weight parts and the content of Be (beryllium) was 0.01 weigh parts. A semi-continuous casting was performed on the above raw material of the Al-Mg alloy plate at a temperature of 700℃, with a diameter of the cast bar of 210mm, a drawing speed of 20 cm/min, and in an atmosphere of Ar and SF₆. RJ-6 (covering agent) was added uniformly in the whole process to avoid burning, and the content of the covering agent was 0.4 weight parts. An elaborate turning was carried out on the surface of the cast bar and a treatment was carried out on the head and tail of the cast bar, then an inspection was carried out on the cast bar, to obtain an Al-Mg alloy plate having a pore with a particle diameter of less than 200μm and an impurity with a particle diameter of less than 200μm. A treatment was carried out on the head and tail of the cast bar to remove the head and tail of the cast bar.

The cast bar was annealed uniformly at a temperature of 350℃ for 5 hours, the extrusion die was preheated to 400℃, and the extrusion temperature was controlled to be 420℃, with an extrusion ratio of 20: 1 and an extrusion speed of 1 m/min, to obtain an Al-Mg alloy plate with a thickness of 10 mm, and a heat conductivity coefficient of 105 w/m·K. The particle diameter of a pore of the Al-Mg alloy plate was 150μm, the particle diameter of an impurity of the Al-Mg alloy plate was 150μm, and the particle diameter of a crystalline grain of the Al-Mg alloy plate was 55μm. A plate including a pore and an impurity with particle diameters of larger than 200μm may be treated as a defective product.

The above plate was rolled at a temperature of 400℃ for 10 times to obtain a plate with a thickness of 10 mm. The plate includes a pore and an impurity with particle diameters of less than 100μm, and a crystalline grain with a particle diameter of 28μm.

Then, the plate was forged with a forging machine at a temperature of 300℃ and polished to obtain a workblank having a surface with a roughness of less than 10μm. The workblank was numerical control manufactured with a numerical control machine tool to obtain a final product with a heat conductivity coefficient of 105 w/m·K. The particle diameter of a pore of the final product was less than 100μm, the particle diameter of an impurity of the final product was less than 100μm, and the particle diameter of a crystalline grain of the final product was 28μm. The yield was 96％after forging and numerical controlling, and when 100 products were processed, 4 products have tiny cracks caused by forging, and a weight falling test was carried out on the rest 96 products without any crack.

Example 3

Based on 100 weight parts of a raw material of the Al-Mg alloy plate, the content of Mg thereof was 88 weight parts, the content of Zn thereof was 4 weight parts, the content of Al thereof was 1 weight part, the content of Mn thereof was 2 weight parts, the content of Si thereof was 0.2 weight parts and the content of Be (beryllium) was 0.4 weigh parts. A semi-continuous casting was carried out on the above raw material of the Al-Mg alloy plate at a temperature of 700℃, with a diameter of the cast bar of 210mm, a drawing speed of 20 cm/min, and in an atmosphere of Ar and SF₆. RJ-6 (covering agent) was added uniformly in the whole process to avoid burning, and the content of the covering agent was 0.5 weight parts. An elaborate turning was carried out on the surface of the cast bar and a treatment was carried out on the head and tail of the cast bar, then an inspection was carried out on the cast bar, to obtain an Al-Mg alloy plate having a pore with a particle diameter of less than 200μm and an impurity with a particle diameter of less than 200μm. A treatment was carried out on the head and tail of the cast bar to remove the head and tail of the cast bar.

The cast bar was annealed uniformly at a temperature of 400℃ for 8 hours, the extrusion die was preheated to 450℃, and the extrusion temperature was controlled to be 420℃, with an extrusion ratio of 15: 1 and an extrusion speed of 2 m/min, to obtain an Al-Mg alloy plate with a thickness of 15 mm, and a heat conductivity coefficient of 110 w/m·K. The particle diameter of a pore of the Al-Mg alloy plate was 150μm, the particle diameter of an impurity of the Al-Mg alloy plate was 150μm, and the particle diameter of a crystalline grain of the Al-Mg alloy plate was 55μm. A plate including a pore and an impurity with particle diameters of larger than 200μm may be treated as a defective product.

The above plate was rolled at a temperature of 400℃ for 10 times to obtain a plate with a thickness of 15 mm. The plate includes a pore and an impurity with particle diameters of less than 100μm, and a crystalline grain with a particle diameter of 27μm.

Then, the plate was forged with a forging machine at a temperature of 200℃ and polished to obtain a workblank having a surface with a roughness of less than 10μm. The workblank was numerical control manufactured with a numerical control machine tool to obtain a final product with a heat conductivity coefficient of 110 w/m·K. The particle diameter of a pore of the final product was less than 100μm, the particle diameter of an impurity of the final product was less than 100μm, and the particle diameter of a crystalline grain of the final product was 27μm. The yield was 97％after forging and numerical controlling, and when 100 products were processed, 3 products have tiny cracks caused by forging, and a weight falling test was carried out on the rest 97 products without any crack.

Example 4

The method for preparing the Al-Mg alloy plate and an Al-Mg alloy plate product are substantially the same as that in Example 2, except that: the rolling process was omitted to obtain a plate with a thickness of 30 mm, the particle diameters of a pore and an impurity of the plate were less than 110μm, and a particle diameter of a crystalline grain of the plate was 50μm. The final product had a heat conductivity coefficient of 90 w/m·K, the particle diameter of a pore of the final product was less than 110μm, the particle diameter of an impurity of the final product was less than 110μm, and the particle diameter of a crystalline grain of the final product was 50μm. The yield was 94％after forging and numerical controlling, and when 100 products were processed, 6 products have tiny cracks caused by forging, and a weight falling test was carried out on the rest 94 products without any crack.

Example 5

The method for preparing the Al-Mg alloy plate and an Al-Mg alloy plate product are substantially the same as that in Example 2, except that: based on 100 weight parts of a raw material of the Al-Mg alloy plate, the content of Mg thereof was 83 weight parts, the content of Zn thereof was 0.5 weight parts, the content of Al thereof was 5 weight parts, the content of Mn thereof was 3 weight parts, and the content of Si thereof was 5 weight parts. The obtained plate had a thickness of 30 mm, the particle diameters of a pore and an impurity of the plate were less than 120μm and a particle diameter of a crystalline grain of the plate was 40μm. The final product had a heat conductivity coefficient of 90 w/m·K, the particle diameter of a pore of the final product was less than 120μm, the particle diameter of an impurity of the final product was less than 120μm, and the particle diameter of a crystalline grain of the final product was 40μm. The yield was 94％ after forging and numerical controlling, and when 100 products were processed, 6 products have tiny cracks caused by forging, and a weight falling test was carried out on the rest 94 products without any crack.

Example 6

The method for preparing the Al-Mg alloy plate and an Al-Mg alloy plate product are substantially the same as that in Example 2, except that: based on 100 weight parts of a raw material of the Al-Mg alloy plate, the content of Mg thereof was 83 weight parts, the content of Zn thereof was 0.5 weight parts, the content of Al thereof was 5 weight parts, the content of Mn thereof was 3 weight parts, and the content of Si thereof was 1 weight part. The obtained plate had a thickness of 30 mm, the particle diameters of a pore and an impurity of the plate were less than 110μm and a particle diameter of a crystalline grain of the plate was 35μm. The final product had a heat conductivity coefficient of 95 w/m·K, the particle diameter of a pore of the final product was less than 110μm, the particle diameter of an impurity of the final product was less than 110μm, and the particle diameter of a crystalline grain of the final product was 35μm. The yield was 95％ after forging and numerical controlling, and when 100 products were processed, 5 products have tiny cracks caused by forging, and a weight falling test was carried out on the rest 95 products without any crack.

Comparative Example 1

In this comparative example, an Al-Mg alloy plate, a method of preparing the same and use thereof were provided.

The method for preparing the Al-Mg alloy plate and an Al-Mg alloy plate product are substantially the same as that in Example 2, except that: the casting was carried out at a temperature of 850℃, the extrusion temperature was 280℃, with an extrusion ratio of 25: 1 and an extrusion speed of 5 m/min, to obtain a plate with a thickness of 4 mm, the particle diameters of a pore and an impurity of the plate were less than 300μm and a particle diameter of a crystalline grain of the plate was 100μm. The final product had a heat conductivity coefficient of 65 w/m·K, the particle diameter of a pore of the final product was less than 300μm, the particle diameter of an impurity of the final product was less than 300μm, and the particle diameter of a crystalline grain of the final product was 100μm. The yield was 86％after forging and numerical controlling, and when 100 products were processed, 14 products have tiny cracks caused by forging, and a weight falling test was carried out on the rest 86 products, and 65％of the rest 86 products did not have any crack.

As can be seen from Examples 1-6 and Comparative Example 1, the Al-Mg alloy plate products prepared from the Al-Mg alloy plates of the present disclosure have a heat conductivity coefficient of 90 w/m·K to 110 w/m·K, a yield of larger than 94％, and 94％of the products do not have any crack after a weight falling test. Therefore, with the Al-Mg alloy plate prepared by the method of the present disclosure, a heat conductivity and a mechanical strength of the Al-Mg alloy plate may be improved, a heat conductivity and a mechanical strength of the electronic products may be improved, and a stability and a consistency of the appearance of the electronic products may be improved.

As can be seen from Example 2 and Example 4, a process of rolling was carried out after extruding, such that a heat conductivity and a mechanical strength of the Al-Mg alloy plate may be improved, a heat conductivity and a mechanical strength of the electronic products may be improved, and a stability and a consistency of the appearance of the electronic products may be improved.

By comparing Example 2 with Examples 5-6 respectively, when the raw material of the Al-Mg alloy plate includes Mg, Zn, Al, Mn and M, in which M is Si and/or Be, based on the total weight of the Al-Mg alloy plate, the content of Mg ranges from 84 wt％to 96.9 wt％, the content of Zn ranges from 0.5wt％to 4wt％, the content of Al ranges from 0.5wt％to 4wt％, the content of Mn ranges from 0.1wt％to 2wt％, the content of M ranges from 0 to 2wt％, and the balance is the impurity, such that a heat conductivity and a mechanical strength of the Al-Mg alloy plate may be improved, a heat conductivity and a mechanical strength of the electronic products may be improved, and a stability and a consistency of the appearance of the electronic products may be improved.

According to embodiments of the present disclosure, the Al-Mg alloy plate has a heat conductivity coefficient larger than 80 w/m·K. In the Al-Mg alloy plate according to embodiments of the present disclosure, a crystalline grain has a particle diameter of less than about 60 μm, a pore has a particle diameter of less than about 200 μm, an impurity has a particle diameter of less than 200 μm, and the yield may reach 94％ or more, such that the heat conductivity and mechanical property of the Al-Mg alloy plate may be improved, and the obtained electronic products may have an improved heat conductivity and mechanical property, and a stable and uniform appearance.

Reference will be made in detail to embodiments of the present disclosure. The embodiments described herein with reference to drawings are explanatory, illustrative, and used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions.

Claims

An Al-Mg alloy plate having a thickness of larger than 5mm, comprising:

a crystalline grain having a crystal grain size of less than about 60 μm；

a pore having a particle diameter of less than about 200 μm； and

an impurity having a particle diameter of less than about 200 μm.
The Al-Mg alloy plate of claim 1, wherein the crystalline grain has a crystal grain size of less than 30 μm.
The Al-Mg alloy plate of claim 1, wherein the pore and the impurity each independently have a particle diameter of less than 100 μm.
The Al-Mg alloy plate of claim 1, wherein the Al-Mg alloy plate has a thickness ranging from 5 mm to 25 mm.
The Al-Mg alloy plate of any of claims 1-4, comprising Mg, Zn, Al, Mn and M, M being at least one selected from silicon and beryllium.
The Al-Mg alloy plate of claim 5, wherein based on the total weight of the Al-Mg alloy plate, the Al-Mg alloy plate comprises:

84 wt％ to 96.9 wt％ of Mg,

0.5 wt％ to 4 wt％ of Zn,

0.5 wt％ to 4 wt％ of Al,

0.1 wt％ to 2 wt％ of Mn,

0 to 2 wt％ of M, and

a balance of the impurity.
The Al-Mg alloy plate of claim 5 or 6, wherein M comprises silicon and beryllium, and a weight ratio of silicon to beryllium ranges from 10:1 to 1:50.
The Al-Mg alloy plate of any of claims 1-4, wherein the Al-Mg alloy plate has a heat conductivity coefficient of larger than 80 w/m·K.
The Al-Mg alloy plate of claim 7, wherein the heat conductivity coefficient of the Al-Mg alloy plate is larger than 100 w/m·K.
A method of preparing an Al-Mg alloy plate, comprising:

casting a raw material of the Al-Mg alloy plate at a temperature of 650℃ to 780℃ to obtain a cast bar； and

extruding the cast bar at a temperature of 380℃ to 480℃, with an extrusion ratio of 5:1 to 20:1, and an extrusion speed of 0.5 m/min to 3 m/min to obtain the Al-Mg alloy plate.
The method of claim 10, wherein the casting comprises semi-continuous casting.
The method of claim 10, further comprising rolling the Al-Mg alloy plate after extruding the cast bar.
The method of claim 10, wherein the raw material of the Al-Mg alloy plate comprises Mg, Zn, Al, Mn and M, with M being selected from silicon and/or beryllium.
The method of claim 13, wherein based on the total weight of the Al-Mg alloy plate, the Al-Mg alloy plate comprises:

84 wt％ to 96.9 wt％ of Mg,

0.5 wt％ to 4 wt％ of Zn,

0.5 wt％ to 4 wt％ of Al,

0.1 wt％ to 2 wt％ of Mn,

0 to 2 wt％ of M, and

a balance of an impurity.
The method of claim 13, wherein M comprises silicon and beryllium, and a weight ratio of silicon to beryllium ranges from 10:1 to 1:50.
An Al-Mg alloy plate prepared by the method of any of claims 10 to 15.
Use of the Al-Mg alloy plate of any of claims 1-9 and 16 in preparing an electronic product.
An electronic product comprising an Al-Mg alloy plate of any of claims 1-9 and 16.
A method for preparing an electronic product comprising:

providing an Al-Mg alloy plate of any of claims 1-9 and 16； and

optionally forming the electronic product.