Aluminum-alloy powder material and method of producing forming material using the same

Abstract

To provide an aluminum-alloy powder material that exhibits reduced internal defects and achieves high strength and a method of producing a forming material using the same.SOLUTION: An aluminum-alloy powder comprises, by mass%, Zn: 4.0-8.0%, Mg: 1.0-2.0%, Cu: 0.10-1.0%, Zr: 0.10-0.25%, Si: 0.01-0.25%, Ti: 0.005-0.05%, Fe: 0.10-0.40%, Mn: 0.004-0.4%, Cr: 0.05% or less, and a total of [Fe + Mn + Zr]: 0.23-1.05%, with the remainder being Al and inevitable impurities, wherein the particle size distribution is d10: 30 μm or less, d50: 45 μm or less, and d90: 70 μm or less, and the apparent density is 1.5 g / cc or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a molding material using aluminum alloy powder.

Background Art

[0002] One type of powder molding is a so-called 3D printer that laminates powder based on 3D CAD design data. For example, Patent Document 1 and Non-Patent Document 2 report on laminated molding using aluminum alloy powder. When using powder of JIS 7000 series high-strength aluminum alloy as a raw material, cracks are likely to occur in the melting method by laser irradiation as shown in Non-Patent Document 1, and the addition of Si has been studied in Patent Document 1 and the like. However, there was a technical problem that sufficient high strength could not be obtained when the addition amount of Si was large.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a powder material of an aluminum alloy with few internal defects and capable of obtaining high strength, and a method for manufacturing a molding material using the same.

Means for Solving the Problems

[0006] The aluminum alloy powder material according to the present invention contains, by mass%, Zn: 4.0 to 8.0%, Mg: 1.0 to 2.0%, Cu: 0.10 to 1.0%, Zr: 0.10 to 0.25%, Si: 0.01 to 0.25%, Ti: 0.005 to 0.05%, with Fe: 0.10 to 0.40%, Mn: 0.004 to 0.4%, Cr: 0.05% or less, and the total of [Fe + Mn + Zr]: 0.23 to 1.05%, and the balance is composed of Al and inevitable impurities, and is a powder of an aluminum alloy characterized in that the particle size distribution is d10: 30 μm or less, d50: 45 μm or less, d90: 70 μm or less, and the apparent density is 1.5 g / cc or more. The present invention is characterized in that the Si content is suppressed to be less than in the prior art.

[0007] Here, the reasons for selecting the components of the powder material are as follows. <Zn, Mg, Cu> Since the aluminum alloy powder according to the present invention aims to obtain high strength after shaping, it is based on the 7000 series alloy of the Al-Zn-Mg system. Therefore, it is set in the range of Zn: 4.0 to 8.0%, Mg: 1.0 to 2.0% by mass%, and further added in the range of Cu: 0.10 to 1.0% to achieve higher strength. <Fe, Zr, Mn, Cr> These components are effective for refining crystal grains, but if there are too many, defects due to excessive precipitates are likely to occur. Therefore, it is set to Fe: 0.10 to 0.40%, Zr: 0.10 to 0.25%, Mn: 0.004 to 0.4%, Cr: 0.05% or less, and the total of [Fe + Mn + Zr] is in the range of 0.23 to 1.05%. <ti> The tissue can be refined in a small amount, and the range is set to 0.005 to 0.05%. <si> Although Si has the effect of suppressing crack generation during solidification after melting the powder by laser irradiation, it causes a decrease in strength. Therefore, the range of Si was set to 0.01 to 0.25%.

[0008] For the aluminum alloy powder, various known atomization methods and the like can be used. As for the particle size distribution, at least those with d50: 45 μm or less are preferable, and further those with d10: 30 μm or less and d90: 70 μm or less are preferable. As for the apparent density, 1.5 g / cc or more is preferable.

[0009] The manufacturing method of the modeling material according to the present invention preferably performs layer manufacturing by a powder bed method and a direct metal laser melting method using the aluminum alloy powder material described in claim 1.

[0010] When a shaped article is obtained in this way, it has a tensile strength of 360 to 450 MPa, a 0.2% proof stress of 340 to 400 MPa, and an elongation of 2 to 10% by heat treatment T6.

Effect of the Invention

[0011] When the aluminum alloy powder according to the present invention is used, a modeling material with high strength and few internal defects can be obtained by a 3D printer.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0013] The shaping material according to the present invention can be formed into a predetermined three-dimensional shape by spreading metal powder on a base plate and melting the metal powder by direct metal laser melting method based on CAD data while welding and solidifying it. For example, using the 3D printer Mlab of Concept Laser, a shaping material with a density of 2.72 - 2.74 (true density ratio 97.1 - 97.9%) can be obtained with a laser output of 120 - 180 W, a laser spot size of 75 μm, a laser scanning speed of 250 - 500 mm / s, a laser pitch of 25 - 73 μm, a powder layer thickness of 25 μm, and a laser irradiation pattern of 5 mm wide island irradiation.

[0014] Also, using the 3D printer M2 of Concept Laser, a shaping material with a density of 2.72 - 2.78 (true density ratio 97.1 - 99.3%) can be obtained with a combination of a base plate temperature of 200 °C, a laser output of 90 - 370 W, a laser spot size of 75 - 400 μm, a laser scanning speed of 100 - 2400 mm / s, a laser pitch of 25 - 133 μm, a powder layer thickness of 25 μm, and a laser irradiation pattern of 5 mm wide island irradiation. In particular, with a combination of a laser output of 90 - 180 W, a laser spot size of 75 - 400 μm, a laser scanning speed of 100 - 750 mm / s, a laser pitch of 25 - 73 μm, a powder layer thickness of 25 μm, and a laser irradiation pattern of 5 mm wide island irradiation, a shaping material with a density of 2.75 - 2.78 (true density ratio 98.2 - 99.3%) can be obtained.

[0015] The composition shown in the table of Fig. 1 indicates the chemical composition of the product after shaping. Considering the evaporation during shaping for Zn, it may be set to 6.0 - 8.0% as powder. Moreover, it may be even more. The shaping material was manufactured and evaluated under the shaping conditions shown in the table of Fig. 2. Here, as the powder shaping machine, the 3D printer M2 of Concept Laser was used, and the temperature of the base plate was set to 200 ± 20 °C. The particle size distribution of the powder used for evaluation was d10: 26.2 μm, d50: 41.7 μm, d90: 62.4 μm, and the apparent density was 1.48 g / cc. Also, T1 shown in the figure is the value immediately after shaping, and T6 is the value after water cooling after solutionizing at 480 °C for 1 hour and performing heat treatment of 110 °C × 6 hours + 140 °C × 12 hours. The mechanical properties were measured using a tensile testing machine conforming to JIS. Figure 3 shows the observation results of the fracture surface after a tensile test, with a tensile test piece cut out from the shaped material fabricated in Example 1. Dimples were observed on the fracture surface, indicating ductile fracture.

[0016] The table in Figure 2 shows the results of Examples 1 to 5. Regarding the shaping conditions, since various levels were set and comparative evaluations were made, they will be described below. In Examples 1 to 5, the laser output was set to 120 W, but the laser output is preferably in the range of 90 to 370 W, more preferably 90 to 180 W. When experiments were conducted with a laser output of 370 W, the Mg and Zn components in the aluminum alloy vaporized, and the alloy composition could not be maintained. Therefore, it is advisable to keep the laser output below 370 W, preferably below 180 W, and heat the base plate to 100 °C or higher. In this example, the laser output was further set to 120 W, and the temperature of the base plate was set in the range of 180 to 220 °C.

[0017] In the table of Figure 2, the scan speed corresponds to the laser scanning speed, and the energy density J / mm 3 is affected by the settings of the laser spot size, line pitch (laser pitch) and scan speed in addition to the laser output. However, when the energy density is less than 900 J / mm 3 the density of the shaped material decreases, and when it exceeds 1100 J / mm 3 it has been clarified that sink marks and cracks are likely to occur during shaping.< / si> < / ti>

Claims

1. An aluminum alloy powder containing, by mass%, Zn: 4.0 to 8.0%, Mg: 1.0 to 2.0%, Cu: 0.10 to 1.0%, Zr: 0.10 to 0.25%, Si: 0.01 to 0.25%, Ti: 0.005 to 0.05%, with Fe: 0.10 to 0.40%, Mn: 0.004 to 0.4%, Cr: 0.05% or less, and the total of [Fe + Mn + Zr]: 0.23 to 1.05%, and the balance being composed of Al and inevitable impurities, The aluminum alloy powder material is characterized in that the particle size distribution is d10: 30 μm or less, d50: 45 μm or less, d90: 70 μm or less, and the apparent density is 1.5 g / cc or more.

2. A method for manufacturing a shaped material, characterized in that the aluminum alloy powder material according to Claim 1 is used for laminated manufacturing by a powder bed method and a direct metal laser melting method.

3. The method for manufacturing a shaped material according to Claim 2, characterized in that it has a tensile strength of 360 to 450 MPa, a 0.2% proof stress of 340 to 400 MPa, and an elongation of 2 to 10% after heat treatment T6.

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