阅读说明：本技术 一种增材制造的铜铁合金及其制备方法 (Additive manufactured copper-iron alloy and preparation method thereof ) 是由 孟祥鹏 冷哲 熊承义 孙文声 王金刚 刘海军 于 2020-07-16 设计创作，主要内容包括：本发明涉及一种增材制造的铜铁合金,其特征在于该铜铁合金的质量百分比组成为Fe：5.0～8.0wt％,RE：0.8～1.5wt％,余量为Cu和不可避免的杂质,杂质含量≤0.01wt％。本发明在铜合金中加入了适量的Fe,明显提高了铜在增材制造过程中对激光的吸收率,使增材制造更加容易进行。向铜合金中加入了适量的稀土,一方面可以改善铜铁合金粉末的显微组织,使其更适合于增材制造工艺,另一方面可以细化Cu相和Fe相的组织,提高铜铁合金的力学性能。(The invention relates to an additive manufactured copper-iron alloy which is characterized by comprising the following components in percentage by mass: 5.0-8.0 wt%, RE: 0.8-1.5 wt%, and the balance of Cu and inevitable impurities, wherein the content of the impurities is less than or equal to 0.01 wt%. According to the invention, a proper amount of Fe is added into the copper alloy, so that the laser absorption rate of copper in the additive manufacturing process is obviously improved, and the additive manufacturing is easier. The addition of a proper amount of rare earth into the copper alloy can improve the microstructure of the copper-iron alloy powder, so that the copper-iron alloy powder is more suitable for the additive manufacturing process, and can refine the structures of a Cu phase and a Fe phase and improve the mechanical property of the copper-iron alloy.)

1. The additive manufacturing copper-iron alloy is characterized in that the composition of the copper-iron alloy in percentage by mass is Fe: 5.0-8.0 wt%, RE: 0.8-1.5 wt%, and the balance of Cu and inevitable impurities, wherein the content of the impurities is less than or equal to 0.01 wt%.

2. The additive manufactured copper-iron alloy according to claim 1, characterized in that: the RE is selected from one or more of light rare earth; or the RE is selected from one or more of heavy rare earths.

3. The additive manufactured copper-iron alloy according to claim 2, wherein: and RE is La and Ce in the light rare earth.

4. The additive manufactured copper-iron alloy according to claim 1, characterized in that: the compactness of the copper-iron alloy is 95-98%.

5. The additive manufactured copper-iron alloy according to claim 1, characterized in that: the grain size of the copper-iron alloy is less than or equal to 50 mu m.

6. The additive manufactured copper-iron alloy according to claim 1, characterized in that: the tensile strength of the copper-iron alloy is 400-460 MPa, the yield strength is 320-410 MPa, the elongation is 16-25%, and the electric conductivity is 55-70% IACS.

7. A method of manufacturing an additively manufactured copper-iron alloy according to any one of claims 1 to 6, characterized by comprising the following manufacturing steps: 1) preparing copper-iron alloy powder by a gas atomization method; 2) and preparing the copper-iron alloy material by a selective laser melting method.

8. The method of making an additively manufactured copper-iron alloy according to claim 7, wherein: the process of the step 1) comprises the following steps: weighing the materials according to the component proportion of the copper-iron alloy material, respectively adding electrolytic Cu, Fe and Cu-RE intermediate alloy into an electromagnetic induction smelting furnace for smelting at the smelting temperature of 1200-1350 ℃, under the protection of inert gas, after molten metal is completely molten, enabling the molten metal to flow out at the speed of 5.0-8.0 kg/min through an atomizing nozzle, wherein the air pressure in the atomizing nozzle is 4.0-5.0 MPa, and atomized metal liquid drops are rapidly solidified to form copper-iron alloy powder.

9. The method of making an additively manufactured copper-iron alloy of claim 8, wherein: screening out copper-iron alloy powder with the size of 35-65 mu m, and putting the copper-iron alloy powder into a vacuum drying oven at 100-150 ℃ for later use.

10. The method of making an additively manufactured copper-iron alloy according to claim 7, wherein: in the step 2): placing the copper-iron alloy powder into a powder cylinder of a selective laser melting additive manufacturing machine, protecting by inert gas, wherein the volume ratio of oxygen content is less than 0.1%, and the process conditions of the selective laser melting method are as follows: the laser power is 450-500W, the diameter of a light spot is 0.06-0.1 mm, the scanning speed is 6-10 m/s, the scanning distance is 0.05-0.16 mm, and the thickness of a powder laying layer is 0.02-0.05 mm.

Technical Field

The invention belongs to the technical field of additive manufacturing of copper alloys, and particularly relates to an additive manufactured copper-iron alloy and a preparation method thereof.

Background

The additive manufacturing technology, also known as rapid prototyping or 3D printing technology, is a manufacturing technology which integrates computer aided design, material processing and forming technology, and based on a digital model file, the special materials such as metal materials, non-metal materials and the like are stacked layer by layer through software and a numerical control system according to the modes of extrusion, sintering, melting, photocuring, spraying and the like to manufacture solid materials. Compared with the traditional manufacturing technology, the additive manufacturing technology has the following advantages: (1) the method is not limited by the shape of the part, and any part with a complex structure can be precisely manufactured; (2) the manufacturing of parts can be rapidly finished without complex processing procedures such as die development, casting, forging, extrusion, rolling, machining and the like; (3) the processing allowance is small, and the raw material waste is less. For metallic materials, a common additive manufacturing process mainly includes: selective Laser Melting (SLM), Selective Laser Sintering (SLS) and Selective Electron Beam Melting (SEBM). The selective laser melting technology has the advantages of high forming precision, good internal quality, high mechanical property and the like, and has a wide application prospect.

At present, products such as titanium alloy, stainless steel, high-temperature nickel-based alloy and the like with excellent performance can be successfully prepared by applying a selective laser melting technology. For example: the invention patent CN104174845B discloses a method for preparing titanium alloy parts by selective laser melting molding; the invention patent CN108339983B discloses a selective laser melting forming method of 304 stainless steel or 304L stainless steel; the invention patent CN109439962B discloses a method for selective laser melting forming of nickel-based superalloy.

However, in the case of copper alloy, the absorption rate of pure copper powder to laser is only 2.0-5.0%, which results in low printing efficiency of pure copper powder and poor product quality, so that the technology for preparing copper alloy by adopting the selective laser melting technology is not mature, and the copper alloy has good electric conductivity and heat conductivity and excellent corrosion resistance and is widely applied to the fields of aerospace, electronic and electrician and the like. At present, along with the shortening of the production period of products and the gradual increase of the requirements of complex precision components, the development of the copper alloy with excellent performance and manufactured by additive manufacturing has important significance.

Disclosure of Invention

The first technical problem to be solved by the present invention is to provide an additive manufactured copper-iron alloy with good absorption rate and excellent comprehensive performance in view of the above-mentioned current state of the art.

The technical scheme adopted by the invention for solving the first technical problem is as follows: the additive manufacturing copper-iron alloy is characterized in that the composition of the copper-iron alloy in percentage by mass is Fe: 5.0-8.0 wt%, RE: 0.8-1.5 wt%, and the balance of Cu and inevitable impurities, wherein the content of the impurities is less than or equal to 0.01 wt%.

The addition of the Fe element can obviously improve the absorptivity of the copper alloy powder to laser, the absorptivity of the pure Cu powder to the laser is only 2.0-5.0%, and after a certain amount of the Fe element is added, the absorptivity of the copper alloy powder to the laser can be obviously improved. However, since the melting point of Cu is only 1083 ℃, which is greatly different from the melting point of Fe of 1538 ℃, this may cause defects due to the fact that high-melting-point materials are not easily melted completely in the additive manufacturing process, and therefore, the content of Fe is not too large, and is controlled to be 5.0 to 8.0 wt%.

The rare earth has a certain purification effect on Cu phase and Fe phase in the alloy, so that the rare earth is more suitable for an additive manufacturing process. On the other hand, the structure of the Cu phase and the Fe phase can be refined, and the mechanical property of the copper-iron alloy is improved. Therefore, in the present invention, 0.8 to 1.5 wt% of RE is added.

The impurity elements have great influence on the additive manufacturing of the copper-iron alloy, and particularly when the impurity elements such as O, S are excessive, the performance of the copper-iron alloy material is influenced. The impurity elements of the invention should be controlled within 0.01 wt%.

Preferably, the RE is selected from one or more of the light rare earths; or the RE is selected from one or more of heavy rare earths.

Preferably, the RE is La and Ce in the light rare earth.

Preferably, the compactness of the copper-iron alloy is 95-98%.

Preferably, the grain size of the copper-iron alloy is less than or equal to 50 μm.

Preferably, the tensile strength of the copper-iron alloy is 400-460 MPa, the yield strength is 320-410 MPa, the elongation is 16-25%, and the electric conductivity is 55-70% IACS.

The second technical problem to be solved by the present invention is to provide a method for preparing an additive manufactured copper-iron alloy in view of the above-mentioned prior art.

The technical scheme adopted by the invention for solving the second technical problem is as follows: a preparation method of an additive manufactured copper-iron alloy is characterized by comprising the following preparation steps: 1) preparing copper-iron alloy powder by a gas atomization method; 2) and preparing the copper-iron alloy material by a selective laser melting method.

Preferably, the process of step 1) is as follows: weighing the materials according to the component proportion of the copper-iron alloy material, respectively adding electrolytic Cu, Fe and Cu-RE intermediate alloy into an electromagnetic induction smelting furnace for smelting at the smelting temperature of 1200-1350 ℃, under the protection of inert gas, after molten metal is completely molten, enabling the molten metal to flow out at the speed of 5.0-8.0 kg/min through an atomizing nozzle, wherein the air pressure in the atomizing nozzle is 4.0-5.0 MPa, and atomized metal liquid drops are rapidly solidified to form copper-iron alloy powder.

Preferably, the copper-iron alloy powder with the size of 35-65 mu m is screened out and is put into a vacuum drying oven with the temperature of 100-150 ℃ for standby.

Preferably, in the step 2): placing the copper-iron alloy powder into a powder cylinder of a selective laser melting additive manufacturing machine, protecting by inert gas, wherein the volume ratio of oxygen content is less than 0.1%, and the process conditions of the selective laser melting method are as follows: the laser power is 450-500W, the diameter of a light spot is 0.06-0.1 mm, the scanning speed is 6-10 m/s, the scanning distance is 0.05-0.16 mm, and the thickness of a powder laying layer is 0.02-0.05 mm.

Compared with the prior art, the invention has the advantages that:

1) according to the invention, a proper amount of Fe is added into the copper alloy, so that the laser absorption rate of copper in the additive manufacturing process is obviously improved, and the additive manufacturing is easier. The addition of a proper amount of rare earth into the copper alloy can improve the microstructure of the copper-iron alloy powder, so that the copper-iron alloy powder is more suitable for the additive manufacturing process, and can refine the structures of a Cu phase and a Fe phase and improve the mechanical property of the copper-iron alloy.

2) The copper-iron alloy material is prepared by adopting an additive manufacturing method, the manufacturing of parts with complex structures can be rapidly finished without complex processing procedures such as die development, casting, forging, extrusion, rolling, machining and the like, the processing allowance is small, and the waste of raw materials is less.

3) The density of the copper-iron alloy material manufactured by the additive manufacturing method is 95-98%, the yield strength is 320-410 MPa, the tensile strength is 400-460 MPa, the elongation is 16-25%, and the electric conductivity is 55-70% IACS, so that the copper-iron alloy material is particularly suitable for preparing electric appliance parts, electronic product parts and the like with complex shapes.

Detailed Description

The present invention will be described in further detail with reference to examples.