CN116287913A - Trace element modified aluminum-lithium alloy powder for additive manufacturing and preparation method thereof - Google Patents

Abstract

The invention discloses a trace element modified aluminum-lithium alloy powder for additive manufacturing and a preparation method thereof. The powder material includes Cu, Li, Mg, Ag, Mn, Zn, Zr, Ti and other alloy elements, and may also contain one or more of rare earth elements Sc, Ce, Er. The preparation method includes the steps of batching, smelting to make rods, powder making, powder sieving and the like. The aluminum-lithium alloy component obtained by using the trace element modified aluminum-lithium alloy powder for additive manufacturing and the preparation method thereof according to the present invention has high density, less serious metallurgical defects (shrinkage porosity, shrinkage cavity, thermal crack) and tensile strength and Excellent elongation and other characteristics.

Description

Trace element modified aluminum-lithium alloy powder for additive manufacturing and preparation method thereof

technical field

The invention belongs to the field of aluminum-lithium alloy materials, and in particular relates to a trace element modified aluminum-lithium alloy powder for additive manufacturing and a preparation method thereof.

Background technique

With the development of major aerospace projects such as large passenger aircraft, manned spaceflight, and deep space exploration, the demand for lightweight materials is increasing. Among them, the update and iteration of lightweight high-strength alloy materials and their preparation technologies is particularly important.

Lithium is the lightest metal element. Adding 1% lithium to aluminum alloy can reduce the density of the alloy by 3% and increase the modulus of elasticity of the alloy by 6%. Its strength is comparable to that of traditional high-strength aluminum alloys. However, at present, commercial aluminum-lithium alloys are almost all deformed aluminum alloys, and traditional processing techniques such as casting, forging, rolling, and extrusion are mainly used to produce aluminum-lithium alloy components. The entire production process has many processing steps and long production cycles, making it difficult to adapt to aviation The production of components in the aerospace field is characterized by many types, small quantities, and complex shapes. At the same time, it is difficult to meet the needs of multiple adjustments and rapid iterations of component parameters during the research and development process.

In recent years, the application of metal additive manufacturing technology in industrial production has gradually increased. Its inherent characteristics make it avoid a large amount of material loss in traditional production processes. At the same time, it caters to the development trend of component design complexity. On the one hand, it has a huge advantage that the traditional forming process cannot match. However, the current main commercial aluminum-lithium alloys are prone to serious metallurgical defects such as shrinkage porosity, shrinkage cavities, and thermal cracks during the additive manufacturing process, which makes it difficult to meet the high forming quality and high reliability requirements of components in the aerospace field.

Contents of the invention

In view of the problem that the main commercial aluminum-lithium alloys are prone to shrinkage porosity, shrinkage cavities, thermal cracks and other serious metallurgical defects in the process of metal additive manufacturing, resulting in poor mechanical properties, the purpose of the present invention is to provide a micro Element-modified aluminum-lithium alloy powder and a preparation method thereof. By optimizing the type and content of alloying elements, an aluminum-lithium alloy with excellent mechanical properties is obtained.

The technical solution of the present invention is: a trace element modified aluminum-lithium alloy powder for additive manufacturing, in addition to Al, at least the following trace elements are included in weight percentage: Cu 3.0-5.0wt%, Li 0.5-2.5wt% , Mg 0.2-1.5wt%, Ag 0.6-1.5wt%, Mn 0.05-0.5wt%, Zn 0.05-0.4wt%, Zr 0.01-0.2wt%, Ti0.01-02wt%, rare earth elements 0-0.5wt% .

In terms of weight percentage, the composition of trace elements is: Cu 3.55-4.20wt%, Li 0.80-1.50wt%, Mg0.30-0.74wt%, Ag 0.60-1.25wt%, Mn 0.05-0.20wt%, Zn 0.05-0.25 wt%, Zr 0.10-0.18wt%, Ti 0.10-0.2wt%.

In terms of weight percentage, the content of impurity elements is Fe<0.03wt%, Si<0.03wt%, Na<0.0005wt%, Ca<0.0005wt%, H<0.0001wt%.

The rare earth element is one or more of Sc, Ce, Er.

The preparation method of said a kind of additive manufacturing trace element modified aluminum-lithium alloy powder comprises the following steps:

Step 1 batching: preparing pure metal raw materials or intermediate alloy raw materials for batching according to the weight percentage of each component element in the aluminum-lithium alloy powder material;

Step 2 Melting rods: Put the ingredients into the vacuum induction melting equipment for melting and casting to make prefabricated alloy rods;

Step 3 pulverization: use the crucible-free electrode induction melting vacuum gas atomization (EIGA) pulverization equipment to atomize the prefabricated alloy rod into pulverization;

Step 4 Powder sieving: Use ultrasonic vibrating sieve equipment to screen the product powder in an argon environment and package it in a powder bottle.

The vacuum induction melting equipment in the step 2 is at least 5Kg level, the protective gas used is argon, the working vacuum degree is ≤0.4Pa, and the pressure rise rate is ≤1Pa/h; in the step 3, there is no crucible electrode induction melting vacuum air The atomization powder making equipment is at least 5Kg level, the protective gas used is argon, the working oxygen content is ≤1000ppm, the working vacuum is ≤0.3Pa, the pressure rise rate is ≤1Pa/h, and the atomizing gas flow rate is ≥1200m ³ /h , atomization rate ≥ 90%.

The particle size range of the product powder screened in step 4 is 15-50 μm.

The application of the trace element modified aluminum-lithium alloy powder for additive manufacturing in the laser powder bed fusion forming component preparation technology.

Beneficial effect:

(1) Compared with the current main commercial aluminum-lithium alloys, the trace element modified aluminum-lithium alloy powder for additive manufacturing in the present invention adjusts the addition of various elements, which can improve the formability and mechanical properties of the alloy; the present invention The trace element modified aluminum-lithium alloy powder for additive manufacturing has a higher Ag content, and Ag can interact strongly with Mg to improve the strength of the alloy and improve the high-temperature heat resistance of the alloy; the additive manufacturing used in the present invention Rare earth elements (such as Sc, Ce, Er, etc.) can be optionally added to the aluminum-lithium alloy powder modified by trace elements, which can further improve the overall performance of the alloy.

(2) Different from the traditional mechanical powder mixing process of various powders or the crucible vacuum induction smelting atomization (VIGA) powder making process, the trace element modified aluminum-lithium alloy powder for additive manufacturing in the present invention adopts a crucible-free electrode Induction smelting vacuum atomization process powder making, powder particle size controllable, the prepared aluminum-lithium alloy powder has higher sphericity and fewer satellite particles, and at the same time can avoid element pollution in the crucible during the powder making process, making the alloy powder The impurity content is reduced. In addition, compared with the plasma rotating electrode method (PREP), the crucible-free electrode induction melting vacuum air atomization process has the advantages of saving materials and lower costs.

(3) Compared with the current main commercial aluminum-lithium alloys, the aluminum-lithium alloy components manufactured by the metal additive manufacturing process using the trace element modified aluminum-lithium alloy powder for additive manufacturing according to the present invention have less shrinkage porosity, Shrinkage cavity, hot crack and other metallurgical defects and higher density, tensile strength and elongation.

Description of drawings

Fig. 1 is the powder particle morphology image of the trace element modified aluminum-lithium alloy powder for additive manufacturing obtained by the preparation method of the trace element modified aluminum-lithium alloy powder for additive manufacturing according to the present invention;

Fig. 2 is the microstructure image of embodiment 1;

Fig. 3 is the microstructure image of embodiment 2;

Fig. 4 is the microstructure image of embodiment 3;

Fig. 5 is the microstructure image of embodiment 4;

FIG. 6 is a microstructure image of Comparative Example 2.

Detailed ways

The technical solution of the present invention will be further described below in conjunction with the accompanying drawings.

The first aspect of the present invention provides a trace element modified aluminum-lithium alloy powder for additive manufacturing. In terms of weight percentage, the main composition of the alloy is: Cu 3.0-5.0wt%, Li 0.5-2.5wt%, Mg0 .2-1.5wt%, Ag 0.6-1.5wt%, Mn 0.05-0.5wt%, Zn 0.05-0.4wt%, Zr 0.01-0.2wt%, Ti 0.01-02wt%, and the balance is Al.

Preferably, in terms of weight percent, the Cu content in the aluminum-lithium alloy powder material is 3.55-4.20wt%. Cu can improve the strength and ductility of the alloy.

Preferably, in terms of weight percentage, the Li content in the aluminum-lithium alloy powder material is 0.80-1.50 wt%. Li can significantly reduce the alloy density and increase the modulus of elasticity.

Preferably, in terms of weight percent, the Mg content in the aluminum-lithium alloy powder material is 0.30-0.74wt%. Mg increases tensile strength and yield strength.

Preferably, in terms of weight percent, the Ag content in the aluminum-lithium alloy powder material is 0.60-1.25wt%. Ag can strongly interact with Mg to promote the precipitation of various strengthening phases; Ag can also promote the formation of phases that hinder dislocation movement, which can greatly improve the mechanical properties and high temperature heat resistance of Al-Li alloys.

Preferably, in terms of weight percentage, the Mn content in the aluminum-lithium alloy powder material is 0.05-0.20 wt%. Mn can reduce alloy anisotropy and improve alloy strength.

Preferably, in terms of weight percent, the Zn content in the aluminum-lithium alloy powder material is 0.05-0.25wt%. Zn can increase the strength of the alloy.

Preferably, in terms of weight percent, the Zr content in the aluminum-lithium alloy powder material is 0.10-0.18wt%. Zr can reduce the stress corrosion tendency and quenching sensitivity of the alloy.

Preferably, in terms of weight percent, the Ti content in the aluminum-lithium alloy powder material is 0.10-0.2wt%. Ti can refine grains and improve the overall performance of the alloy.

Preferably, in terms of weight percentage, the content of impurity elements in the aluminum-lithium alloy powder material is Fe<0.03wt%, Si<0.03wt%, Na<0.0005wt%, Ca<0.0005wt%, H<0.0001wt%.

Preferably, the aluminum-lithium alloy powder material may also contain one or more of rare earth elements Sc, Ce, Er, and the total content thereof is 0-0.5wt% in weight percentage. Sc, Ce, and Er can refine grains, inhibit recrystallization and weaken the grain boundary weakening caused by impurity elements, improve the plasticity, strength, fracture toughness and corrosion resistance of the alloy, and improve the overall performance of the alloy.

The second aspect of the present invention provides a method for preparing aluminum-lithium alloy powder modified with trace elements for additive manufacturing, the method comprising the following steps:

Step 1 batching: preparing pure metal raw materials or intermediate alloy raw materials for batching according to the weight percentage of each component element in the aluminum-lithium alloy powder material;

Step 2 Melting rods: Put the ingredients into the vacuum induction melting equipment for melting and casting to make prefabricated alloy rods;

Step 3: pulverizing: the prefabricated alloy rod is atomized and pulverized by using a crucible-less electrode induction melting vacuum gas atomization (EIGA) pulverizing equipment.

Step 4 Powder sieving: use ultrasonic vibrating sieve equipment to screen powders with a particle size of 15-100 μm in an argon environment, and package them in powder bottles.

Preferably, the vacuum induction melting equipment in the step 2 is at least 5Kg level, the protective gas used is argon, the working vacuum degree is ≤0.4Pa, and the pressure rise rate is ≤1Pa/h.

Preferably, in the step 3, the induction melting vacuum atomization powder making equipment without crucible electrodes is at least 5Kg level, the protective gas used is argon, the working oxygen content is ≤1000ppm, the working vacuum degree is ≤0.3Pa, and the pressure rise is Rate≤1Pa/h, atomization gas flow rate≥1200m ³ /h, atomization rate≥90%.

Preferably, the particle size range of the powder screened in step 4 is 15-50 μm.

The third aspect of the present invention provides a laser powder bed fusion forming aluminum-lithium alloy component. The trace element modified aluminum-lithium alloy powder for additive manufacturing obtained by the preparation method is formed by laser powder bed fusion forming technology and After proper heat treatment, it has high density, less serious metallurgical defects such as shrinkage porosity, shrinkage cavity and thermal crack, and has excellent tensile strength and elongation.

Example 1

Embodiment 1 of the present invention provides a trace element modified aluminum-lithium alloy powder for additive manufacturing. In terms of weight percentage, the main composition of the aluminum-lithium alloy powder material is: Cu 4.00wt%, Li 1.00wt%, Mg 0.52wt%, Ag0.65wt%, Mn 0.06wt%, Zn 0.06wt%, Zr 0.15wt%, Ti 0.15wt%, the balance is Al and impurities.

This embodiment also provides a method for preparing aluminum-lithium alloy powder modified with trace elements for additive manufacturing. The method includes the following steps:

Step 1 batching: preparing pure metal raw materials or intermediate alloy raw materials for batching according to the weight percentage of each component element in the aluminum-lithium alloy powder material;

Step 2 Melting rods: Put the ingredients into the vacuum induction melting equipment for melting and casting to make prefabricated alloy rods;

Wherein, the vacuum induction melting equipment is 5Kg grade, the protective gas used is argon, the working vacuum degree is 0.4Pa, and the pressure rise is 1Pa/h.

Step 3: pulverizing: the prefabricated alloy rod is atomized and pulverized by using a crucible-less electrode induction melting vacuum gas atomization (EIGA) pulverizing equipment.

Among them, the vacuum air atomization pulverization equipment without crucible electrode induction melting is 5Kg, the protective gas used is argon, the working oxygen content is 1000ppm, the working vacuum is 0.29Pa, the pressure rise rate is 1Pa/h, and the atomization The gas flow rate is 1500m ³ /h, and the atomization rate is 92%.

Step 4 Powder sieving: use ultrasonic vibrating sieve equipment to sieve powders with a particle size of 15-50 μm in an argon environment, and package them in powder bottles.

This embodiment also provides a laser powder bed fusion forming component, the preparation method is as follows:

The trace element-modified aluminum-lithium alloy powder for additive manufacturing prepared by the method for preparing the trace-element-modified aluminum-lithium alloy powder for additive manufacturing was dried in a vacuum oven at 90° C. for 8 hours. After drying, laser powder bed fusion forming technology is used to form. The forming process parameters are: laser power 200W, scanning speed 100mm/s, scanning distance 90μm, scanning layer thickness 50μm. Formed parts are obtained after laser powder bed fusion forming and T8 heat treatment.

Example 2

Embodiment 2 of the present invention provides a trace element modified aluminum-lithium alloy powder for additive manufacturing. In terms of weight percentage, the main composition of the aluminum-lithium alloy powder material is: Cu 4.00wt%, Li 1.00wt%, Mg 0.52wt%, Ag0.65wt%, Mn 0.06wt%, Zn 0.06wt%, Zr 0.15wt%, Ti 0.15wt%, Sc 0.06wt%, the balance is Al and impurities. The preparation method of the alloy powder is the same as in Example 1.

This embodiment also provides a component formed by laser powder bed fusion, and the preparation method of the component is the same as that in Embodiment 1.

Example 3

Embodiment 3 of the present invention provides a trace element modified aluminum-lithium alloy powder for additive manufacturing. In terms of weight percentage, the main composition of the aluminum-lithium alloy powder material is: Cu 4.00wt%, Li 1.00wt%, Mg 0.52wt%, Ag0.65wt%, Mn 0.06wt%, Zn 0.06wt%, Zr 0.15wt%, Ti 0.15wt%, Sc 0.06wt%, Ce0.04wt%, the balance is Al and impurities. The preparation method of the alloy powder is the same as in Example 1.

This embodiment also provides a component formed by laser powder bed fusion, and the preparation method of the component is the same as that in Embodiment 1.

Example 4

Embodiment 4 of the present invention provides a trace element modified aluminum-lithium alloy powder for additive manufacturing. In terms of weight percentage, the main composition of the aluminum-lithium alloy powder material is: Cu 4.00wt%, Li 1.00wt%, Mg 0.52wt%, Ag0.65wt%, Mn 0.06wt%, Zn 0.06wt%, Zr 0.15wt%, Ti 0.15wt%, Sc 0.06wt%, Ce0.04wt%, Er 0.05wt%, the balance is Al and impurities . The preparation method of the alloy powder is the same as in Example 1.

This embodiment also provides a component formed by laser powder bed fusion, and the preparation method of the component is the same as that in Embodiment 1.

Comparative example 1

Comparative Example 1 of the present invention provides a trace element modified aluminum-lithium alloy powder for additive manufacturing. The material composition of the aluminum-lithium alloy powder is the same as that of Example 1, and the preparation method of the alloy powder is roughly the same as that of Example 1. The only difference is that in this comparative example, the crucible vacuum induction melting atomization (VIGA) powder making equipment is used instead of the crucible electrode induction melting vacuum gas atomization (EIGA) powder making equipment, that is, used in the preparation method step 5 The crucible vacuum induction melting atomization (VIGA) powder making equipment atomizes the prefabricated alloy rod to make powder.

Among them, the crucible vacuum induction smelting atomization pulverization equipment is 5Kg grade, the protective gas used is argon, the working oxygen content is 1000ppm, the working vacuum degree is 0.29Pa, the pressure rise rate is 1Pa/h, and the atomizing gas flow rate is 1500m3 /h, the atomization rate is 92%.

Comparative example 2

Comparative example 2 of the present invention provides a laser powder bed fusion forming component, the component material is 2195 aluminum-lithium alloy (see 2195 (2195-T8) Aluminum:: MakeltFrom.com), the preparation method and implementation of the component alloy powder The same as Example 1, the preparation method of the laser powder bed fusion forming component is the same as that of Example 1.

Comparative example 3

Comparative Example 3 of the present invention provides a trace element modified aluminum-lithium alloy powder for additive manufacturing, the aluminum-lithium alloy powder material composition is Cu 4.00wt%, Li 1.00wt%, Mg 0.52wt%, Mn 0.06wt% , Zn 0.06wt%, Zr 0.15wt%, Ti 0.15wt%, Sc 0.06wt%, Ce 0.04wt%, Er0.05wt%, the balance is Al and impurities, that is, the aluminum-lithium alloy described in Example 4 of the present invention The main compositional difference of powder materials only exists in the amount of trace element Ag added. The preparation method of the alloy powder is the same as in Example 1.

This comparative example also provides a laser powder bed fusion forming component, the preparation method of which is the same as that of Example 1.

The properties of the trace element modified aluminum-lithium alloy powders prepared in Comparative Example 1 and Example 1 for additive manufacturing are shown in Table 1 below

Table 1

The properties of the laser powder bed fusion formed components prepared by Comparative Example 2, Comparative Example 3 and Examples 1-4 are shown in Table 2 below:

Table 2

Claims (8)

1. The microelement modified aluminum lithium alloy powder for additive manufacturing is characterized by comprising the following microelements in percentage by weight besides Al: 3.0 to 5.0wt percent of Cu, 0.5 to 2.5wt percent of Li, 0.2 to 1.5wt percent of Mg, 0.6 to 1.5wt percent of Ag, 0.05 to 0.5wt percent of Mn, 0.05 to 0.4wt percent of Zn, 0.01 to 0.2wt percent of Zr, 0.01 to 0.2wt percent of Ti and 0 to 0.5wt percent of rare earth element.

2. The trace element modified aluminum lithium alloy powder for additive manufacturing according to claim 1, wherein the trace element composition is as follows in weight percent: 3.55 to 4.20 weight percent of Cu, 0.80 to 1.50 weight percent of Li, 0.30 to 0.74 weight percent of Mg, 0.60 to 1.25 weight percent of Ag, 0.05 to 0.20 weight percent of Mn, 0.05 to 0.25 weight percent of Zn, 0.10 to 0.18 weight percent of Zr and 0.10 to 0.2 weight percent of Ti.

3. The trace element modified aluminum lithium alloy powder for additive manufacturing according to claim 1 or 2, wherein the impurity element content is less than 0.03wt% of Fe, less than 0.03wt% of Si, less than 0.0005wt% of Na, less than 0.0005wt% of Ca, and less than 0.0001wt% of H.

4. The trace element modified aluminum lithium alloy powder for additive manufacturing according to claim 3, wherein the rare earth element is one or more of Sc, ce and Er.

5. The method for preparing the trace element modified aluminum lithium alloy powder for additive manufacturing according to any one of claims 1 to 4, which is characterized by comprising the following steps:

step 1, batching: preparing a pure metal raw material or a master alloy raw material according to the weight percentage of each component element in the aluminum lithium alloy powder material for batching;

and 2, smelting and rod making: placing the ingredients into vacuum induction smelting equipment for smelting and casting to prepare a prefabricated alloy rod;

and 3, pulverizing: atomizing the prefabricated alloy rod into powder by using crucible-free electrode induction smelting vacuum air atomization (EIGA) powder making equipment;

and 4, sieving: and screening out product powder in an argon environment by using ultrasonic vibration screen equipment, and packaging the product powder in a powder bottle.

6. The preparation method according to claim 5, wherein the vacuum induction melting equipment in the step 2 is at least 5Kg grade, the used shielding gas is argon, the working vacuum degree is less than or equal to 0.4Pa, and the pressure rise rate is less than or equal to 1Pa/h; the vacuum atomization powder making equipment for crucible-free electrode induction smelting in the step 3 is at least 5Kg grade, the used shielding gas is argon, the working oxygen content is less than or equal to 1000ppm, the working vacuum degree is less than or equal to 0.3Pa, the pressure rise rate is less than or equal to 1Pa/h, and the flow rate of atomization gas is more than or equal to 1200m ³ And/h, the atomization rate is more than or equal to 90 percent.

7. The method according to claim 5 or 6, wherein the particle size of the product powder selected in step 4 is in the range of 15-50. Mu.m.

8. Use of the trace element modified aluminum lithium alloy powder for additive manufacturing according to any one of claims 1-4 in a laser powder bed fusion forming member preparation technique.

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