WO2023019697A1

WO2023019697A1 - High-strength aluminum alloy powder for 3d printing and preparation method for high-strength aluminum alloy powder

Info

Publication number: WO2023019697A1
Application number: PCT/CN2021/121982
Authority: WO
Inventors: 聂祚仁; 郭彦梧; 黄晖; 魏午; 文胜平; 高坤元; 吴晓蓝; 荣莉
Original assignee: 北京工业大学
Priority date: 2021-08-17
Filing date: 2021-09-30
Publication date: 2023-02-23
Also published as: CN113684403A

Abstract

A high-strength aluminum alloy powder for 3D printing and a preparation method for the high-strength aluminum alloy powder, relating to the technical field of special materials for additive manufacturing (also known as 3D printing). The compositions of the alloy are calculated according to a mass percentage: 3.0%-8.0% of Mg, 0.1%-1.2% of Er, 0.5%-2.0% of Zr, 0.3%-1.0% of Mn, 0.01%-2.0% of Si, the total content of the other unlisted metal elements except Al not exceeding 0.5wt%, the balance of Al. The high-strength aluminum alloy powder can effectively inhibit cracks of an AlMg alloy in the 3D printing process and has the remarkable fine grain and precipitation strengthening effect, the yield strength exceeds 400 MPa after heat treatment, the tensile strength exceeds 500 MPa, and the elongation percentage exceeds 10%. The aluminum alloy powder effectively solves the problems that the AlMg alloy is low in strength and poor in formability.

Description

A kind of high-strength aluminum alloy powder for 3D printing and preparation method thereof

technical field

The invention belongs to the technical field of special materials for additive manufacturing (also known as 3D printing), and in particular relates to a 3D printing high-strength aluminum alloy powder and a preparation method thereof.

Background technique

Additive manufacturing technology, also known as 3D printing technology, quickly manufactures parts with extremely complex shapes and internal structures through the principle of "layer-by-layer manufacturing and layer-by-layer superposition", which saves a lot of materials and time compared with traditional subtractive manufacturing cost. In the field of metal 3D printing, selective laser melting (SLM) technology is the most widely used and researched laser additive manufacturing technology. Aluminum and aluminum alloys are widely used in aerospace, transportation, mechanical construction, packaging, electrical engineering, etc. field has a wide range of applications. However, in the field of special materials for additive manufacturing, the most widely used aluminum alloys are mainly AlSi alloys, such as AlSi10Mg and AlSi12. Although the AlSi alloy has good formability and no cracks under the SLM process, its mechanical properties are poor, the yield strength is generally lower than 300MPa, and the elongation is lower than 15%. Airbus Group has developed a Sc-Zr modified AlMg alloy, which not only can suppress cracks after forming, but also has a yield strength of over 400MPa and an elongation of over 10% after heat treatment. However, the price of Sc is too expensive, so that the price of AlMg alloy powder modified by Sc and Zr is much higher than that of AlSi alloy powder. Therefore, in terms of special materials for aluminum alloy additive manufacturing, there are common problems such as few types of materials that can be used, poor mechanical properties, and high prices.

Contents of the invention

In order to solve the problem that the high-strength aluminum alloy is easy to crack during the 3D printing process, the addition of alloy elements is single and expensive, the present invention replaces Sc-Zr composite microalloying with Er-Zr composite microalloying, and adjusts the added Er, Zr The proportional relationship of the element content, through the addition of a large amount of Zr elements, suppresses the cracks of the AlMg alloy, and focuses on the synergistic effect of Er-Zr to significantly improve the strength of the alloy. Since the price of Er is much lower than that of Sc, the cost of high-strength aluminum alloy powder for 3D printing is significantly reduced.

The technical solution of the present invention provides a 3D printing high-strength aluminum alloy powder, mainly containing Mg, Er, Zr, Si, Mn elements, in terms of mass percentage, wherein Mg content is 3.0-8.0%, Er content is 0.1-1.2%, The content of Zr is 0.5-2.0%, the content of Mn is 0.3-1.0%, the content of Si is 0.01-2.0%, the total content of other unlisted metal elements except Al is not more than 0.5wt%, and the rest is Al.

As one of the embodiments of the present invention, the aluminum alloy material includes the following components in mass fraction: Mg content is 3.0-8.0%, Er content is 0.3-0.5%, Zr content is 1.0-1.2%, Mn content is 0.5% ~0.8%, Si content is 0.01~0.1%, and the rest is Al.

As one of the embodiments of the present invention, the aluminum alloy material includes the following components in mass fraction: Mg content is 3.0-8.0%, Er content is 0.5-0.8%, Zr content is 1.3-1.6%, Mn content is 0.5% ~0.8%, Si content is 0.01~0.1%, and the rest is Al.

As one of the embodiments of the present invention, the aluminum alloy material includes the following components in mass fraction: Mg content 3.0-8.0%, Er content 0.3-0.5%, Zr content 1.0-1.2%, Mn content 0.5- 0.8%, the Si content is 1.0-1.6%, and the rest is Al.

As one of the embodiments of the present invention, the aluminum alloy material includes the following components in mass fraction: Mg content 3.0-8.0%, Er content 0.5-0.8%, Zr content 1.3-1.6%, Mn content 0.5- 0.8%, the Si content is 1.0-1.6%, and the rest is Al.

The present invention also provides a method for preparing the above-mentioned aluminum alloy, comprising the following steps:

(1) Carry out batching with pure metal/master alloy as raw material;

(2) heating and melting raw materials and atomizing powder;

(3) Dry the collected metal powder, and obtain powder with a particle size distribution of 15-63 μm after classification.

(4) Sieve the metal powder, dry it in a vacuum oven, pour it into the powder supply chamber of the 3D printing equipment and flush it with an inert gas to reduce the oxygen content to below 0.1%.

Application method:

Design the part model that needs to be printed, add supports and slices to the 3D model, and the 3D printing equipment uses optimized forming parameters to melt and solidify the 3D digital model layer by layer.

The atomization described in the preparation method is vacuum air atomization.

The inert gas described in the preparation method is argon.

The layer-by-layer melting and solidification forming described in the application method includes but is not limited to the selective laser melting (SLM) process. The forming parameters used in the SLM process are: laser power 300-380W, scanning speed 800-1600mm/s, scanning distance 0.1-0.15mm, layer thickness 0.03-0.06mm;

Benefits of the present invention: adding a large amount of Zr element forms Al ₃ Zr primary phase to refine grain size and suppresses solidification cracks; adding Er element forms grain boundary Al ₃ Er phase, which can effectively prevent grain size coarsening during heat treatment; The addition of Si element can increase the diffusion rate of Er and Zr, promote the large amount of dispersed precipitation of Al ₃ (Er, Zr) precipitate, and the Al ₃ (Er, Zr) dispersed phase has a significant effect of precipitation strengthening. Therefore, after aging heat treatment, the yield strength exceeds 400MPa, the tensile strength exceeds 500MPa, and the elongation exceeds 10%. Its performance is better than that of AlSi alloy, and it is equivalent to that of Sc-Zr modified AlMg alloy. However, compared with Sc-Zr modified high-strength aluminum alloy powder, the cost of raw materials is reduced by 300,000 (per ton). The invention expands the types of added elements for 3D printing AlMg alloy microalloying, solves the problems of easy cracking and poor performance of high-strength aluminum alloys, and significantly reduces the cost of high-strength aluminum alloys for 3D printing.

Description of drawings

Figure 1 is a morphological view of the 3D printed high-strength aluminum alloy powder prepared in Example 1 of the present invention.

Fig. 2 is a SEM structure diagram of the 3D printed high-strength aluminum alloy prepared in Example 1 of the present invention.

FIG. 3 is a SEM structure diagram of the 3D printed aluminum alloy prepared in Comparative Example 1 of the present invention.

Detailed ways

The present invention will be further described below in conjunction with embodiment and comparative example, the embodiment adopted herein refers to that the present invention has at least one implementation mode, but the present invention can also be realized in other ways different from this embodiment, so the present invention does not Be limited by the specific examples disclosed below.

Unless otherwise specified, the percentages in the present invention are percentages by mass, and the aluminum alloy composition adopts the general expression in this field, for example, the aluminum alloy composition of Al-6.0Mg-0.7Mn-0.4Er-1.2Zr is: 6.0%Mg, 0.7 %Mn, 0.4% Er, 1.2% Zr, and the rest are Al.

Example 1

The melting composition in a vacuum furnace is Al-6.0Mg-0.7Mn-0.4Er-1.2Zr, and the content of other impurity elements is controlled to be less than 0.1%.

The preparation method of above-mentioned alloy powder:

(1) Select pure Al, pure Mg, Al-5.0% Er master alloy, Al-10.0% Zr master alloy, Al-20.0% Mn master alloy, put them into the crucible according to a certain ratio, first vacuumize and then fill with high-purity Argon is used for smelting. After fully melting, gas atomization powder is carried out in the temperature range of 800-840 degrees and under argon atmosphere. After the liquid is crushed into spherical particles and cooled, the powder is collected and sieved, and finally the pellets are collected. Powder with diameter distribution between 15-63μm (as shown in Figure 1).

(2) Sieve the powder under a 100-mesh sieve, and place it in a vacuum oven for drying at 80°C for 6 hours.

(3) Design the three-dimensional model of the standard tensile specimen, and perform layered slices. Using the SLM Solution M280 metal printer, the preheating temperature is 150 degrees, the forming laser power is 350W, the scanning speed is 1000mm/s, the scanning distance is 0.13mm, and the layer thickness is 0.03mm. Carry out heat treatment at 375 degrees for 10 hours.

The aluminum alloy prepared by the above method suppresses internal cracks (as shown in Figure 2) and refines the grain size through the addition of a large amount of Zr elements, and the average grain size is only 3.3um. The recrystallization and grain growth stabilized the grain size, and after 10 hours of heat treatment at 375 degrees, a large amount of Al ₃ (Er, Zr) precipitated phase was precipitated, which greatly improved the strength of the sample. According to the GB/T 228.1-2010 standard, the mechanical properties are tested, the yield strength is 430MPa, the tensile strength is 500MPa, and the elongation is 20%.

Example 2

The smelting composition in a vacuum furnace is Al-4.0Mg-0.7Mn-0.8Er-1.5Zr-1.6Si, and the content of other impurity elements is controlled to be less than 0.1%.

The preparation method of above-mentioned alloy powder:

(1) Select pure Al, pure Mg, Al-5.0% Er master alloy, Al-10.0% Zr master alloy, Al-20.0% Mn master alloy and Al-21.0Si master alloy, put them into the crucible according to a certain ratio After vacuuming, fill it with high-purity argon for smelting. After fully melting, carry out gas atomization powder production in the temperature range of 800-820 degrees under an argon atmosphere. After the liquid is crushed into spherical particles and cooled, the powder is collected and processed. Sieve the powder, and finally collect the powder with particle size distribution between 15-63um.

(3) Design the three-dimensional model of the standard tensile specimen, and perform layered slices. Using SLM Solution M280 metal printer, the preheating temperature is 200 degrees, the forming laser power is 380W, the scanning speed is 1250mm/s, the scanning distance is 0.13mm, and the layer thickness is 0.03mm. Carry out heat treatment at 350 degrees for 8 hours.

The aluminum alloy prepared by the above method suppresses internal cracks and refines the grain size through the addition of a large amount of Zr elements. The average grain size is about 2.0um, and the Er element inhibits recrystallization and grain growth during heat treatment. Large, stable grain size; Si accelerates the diffusion rate of Er and Zr elements, increases the number of Al ₃ (Er, Zr) precipitates, and precipitates Mg ₂ Si precipitates during the aging process, improving the strength of the sample According to the GB/T 228.1-2010 standard, the mechanical properties are tested, the yield strength is 480MPa, the tensile strength is 530MPa, and the elongation is 12%.

Comparative example 1

The smelting composition in a vacuum furnace is Al-5.0Mg-0.7Mn-0.4Er-0.3Zr, and the content of other impurity elements is controlled to be less than 0.1%.

The preparation method of above-mentioned alloy powder:

(1) Select pure Al, pure Mg, Al-5.0% Er master alloy, Al-10.0% Zr master alloy, Al-20.0% Mn master alloy, put them into the crucible according to a certain ratio, first vacuumize and then fill with high-purity Argon is used for smelting. After fully melting, gas atomization powder is carried out in the temperature range of 800-840 degrees under an argon atmosphere. After the liquid is crushed into spherical particles and cooled, the powder is collected and sieved, and finally the pellets are collected. Powder with diameter distribution between 15-63um.

(3) Design the three-dimensional model of the standard tensile specimen, and perform layered slices. Using the SLM Solution M280 metal printer, the preheating temperature is 200 degrees, the forming laser power is 350W, the scanning speed is 1200mm/s, the scanning distance is 0.13mm, and the layer thickness is 0.03mm. Carry out heat treatment at 375 degrees for 10 hours.

The Zr element content of the aluminum alloy in the comparative example is not within the claims of the present invention, and a large number of cracks (as shown in Figure 3 ) have occurred inside the formed sample and the grain size is coarse, with an average grain size of 12um; the sample formed before aging The morphological hardness is 115HV, and the hardness of 122HV after peak aging has not increased significantly, which means that the number of precipitated phases is small and there is no significant precipitation strengthening effect; the mechanical properties are tested according to the GB/T 228.1-2010 standard. Due to the existence of cracks, the yield The strength is only 170MPa, the tensile strength is 210MPa, and the elongation is 2%.

Claims

A high-strength aluminum alloy powder for 3D printing, characterized in that the aluminum alloy powder mainly includes Mg, Er, Zr, Si, Mn alloy elements, and the content of Mg is 3.0-8.0%, Er The content of Zr is 0.1-1.2%, the content of Zr is 0.5-2.0%, the content of Mn is 0.3-1.0%, the content of Si is 0.01-2.0%, and the total content of other unlisted metal elements except Al is not more than 0.5wt%. for Al.
The aluminum alloy powder according to claim 1, characterized in that it comprises the following components in mass fraction: Mg content is 3.0-8.0%, Er content is 0.3-0.5%, Zr content is 1.0-1.2%, Mn content is 0.5% ～0.8%, Si content is 0.01～0.1%, the rest is Al;

Or the aluminum alloy powder includes the following components in mass fraction: Mg content is 3.0-8.0%, Er content is 0.5-0.8%, Zr content is 1.3-1.6%, Mn content is 0.5-0.8%, Si content is 0.01% ~0.1%, the rest is Al;

Or the aluminum alloy powder includes the following components in mass fraction: Mg content 3.0-8.0%, Er content 0.3-0.5%, Zr content 1.0-1.2%, Mn content 0.5-0.8%, Si content 1.0% ~1.6%, the rest is Al;

Or the aluminum alloy powder includes the following components in mass fraction: Mg content 3.0-8.0%, Er content 0.5-0.8%, Zr content 1.3-1.6%, Mn content 0.5-0.8%, Si content 1.0% ~1.6%, the rest is Al.
The preparation method of aluminum alloy powder described in claim 1 or 2, is characterized in that, comprises the steps:

(1) Carry out batching with pure metal/master alloy as raw material;

(2) heating and melting raw materials and atomizing powder;

(3) Dry the collected metal powder, and obtain powder with a particle size distribution of 15-63 μm after classification.

(4) Sieve the metal powder, dry it in a vacuum oven, pour it into the powder supply chamber of the 3D printing equipment and flush it with an inert gas to reduce the oxygen content to below 0.1%.
The preparation method according to claim 3, characterized in that the atomization is vacuum air atomization.
The preparation method according to claim 3, wherein the inert gas is argon.
The application method of aluminum alloy powder according to claim 1 or 2, characterized in that, after pouring the aluminum alloy powder into the powder supply chamber of the 3D printing equipment and flushing the inert gas to reduce the oxygen content to below 0.1%, the design needs to be printed 3D printing equipment uses optimized forming parameters to melt and solidify the 3D digital model layer by layer.
The preparation method according to claim 6, wherein the layer-by-layer melting and solidification forming includes but is not limited to the selective laser melting (SLM) process; wherein the forming parameters used in the SLM process are: laser power 300-380W, scanning speed 800- 1600mm/s, scanning distance 0.1-0.15mm, layer thickness 0.03-0.06mm.