Aluminum alloy-based composite and producing method thereof

Abstract

To provide an aluminum alloy-based composite having a fine and dense structure, high strength and excellent ductility and a method for producing the same.SOLUTION: Aluminum alloy billets are produced using additive manufacturing, and aluminum alloy-based composites are manufactured by extruding the aluminum alloy billets. The aluminum alloy-based composites have an average grain diameter of 10 μm or less in a cross-section perpendicular to the extrusion direction, with grains oriented in a <001> direction making up 10% or more and grains in a <112> direction making up 50% or more.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to an aluminum alloy profile and a method for producing the same. [Background technology]

[0002] Aluminum alloy shapes can be formed into complex product shapes by processing such as extrusion and rolling, and A6000 series aluminum alloy shapes in particular have excellent extrusion processability and formability and are widely used as building materials and transportation materials (see, for example, Patent Document 1). Conventionally, aluminum alloy shapes have been produced by first producing an aluminum alloy billet by a casting method such as DC casting (semi-continuous casting) or hot top casting, and then subjecting the billet to extrusion processing or the like (see, for example, Patent Documents 2 to 4).

[0003] However, since extrusion is a hot dynamic processing method and recrystallization easily proceeds, there is a problem that the aluminum alloy shape after extrusion has a recrystallized structure, and elongation is easily deteriorated due to the influence of grain boundary precipitates, which often leads to cracking or breakage during processing. Therefore, a refiner is added to the raw material of the billet (for example, see Patent Document 5 or 6). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. WO2007 / 111002 [Patent Document 2] JP 2023-72081 A [Patent Document 3] JP 2015-25193 A [Patent Document 4] Patent No. 5830006 [Patent Document 5] Special Publication No. 2022-554163 [Patent Document 6] Patent Publication No. 2021-134923 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even if a grain refiner is added as described in Patent Documents 5 and 6, there is a problem that the structure of the billet cannot be refined during casting, and it is difficult to obtain fine crystals as the structure of the aluminum alloy shaped material. In addition, there is also a problem that the addition of a grain refiner tends to involve inclusions in the composition of the aluminum alloy shaped material and tends to leave voids, thereby decreasing the strength and ductility of the aluminum alloy shaped material.

[0006] The present invention has been made in light of the above-mentioned problems, and has an object to provide an aluminum alloy extrusion having a fine and dense structure and having high strength and excellent ductility, and a method for manufacturing the same. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides an aluminum alloy profile manufactured by extrusion, the aluminum alloy profile having an average grain size of 10 μm or less in a cross section perpendicular to the extrusion direction, <001> More than 10% of grains are of the same orientation. <112> It is characterized by having more than 50% of crystal grains in the same orientation.

[0008] The aluminum alloy shaped material according to the present invention has a fine and dense structure with an average crystal grain size of 10 μm or less in a cross section perpendicular to the extrusion direction. The aluminum alloy shaped material according to the present invention has high strength and excellent ductility, and is about 20 to 30% stronger and 40% stronger than conventional extruded materials using billets produced by casting. Here, ductility is represented by the breaking elongation in a tensile test (hereinafter the same). The aluminum alloy shaped material according to the present invention can be used, for example, for building sashes, automobile bumpers, aluminum foil, etc.

[0009] In the aluminum alloy profile according to the present invention, the crystal grains preferably have a structure in which the crystal grains are elongated and fibrous along the extrusion direction, and the aspect ratio of the crystal grains is preferably the ratio of the length of the crystal grains in the extrusion direction to the length of the crystal grains in the extrusion direction, and the average aspect ratio is preferably 0.5 or less. In this case, it is preferable that the aluminum alloy profile has a rectangular plate shape elongated in the extrusion direction, and in a cross section perpendicular to the plate width direction, the proportion of crystal grains having the aspect ratio of 0.5 or less is 50% or more, and the proportion of crystal grains having the aspect ratio of 0.65 or less is 90% or more. In these cases, since the crystal grains are elongated and fibrous and have a fine structure, it is possible to obtain higher strength and superior ductility than conventional extruded profiles produced by a casting method having an equiaxed crystal structure.

[0010] In the aluminum alloy profile according to the present invention, the average grain size of the grains is preferably 5 μm or less. In this case, it is preferable that the ratio of grains having a grain size of 5 μm or less is 70% or more, and the ratio of grains having a grain size of 10 μm or less is 90% or more. In these cases, since the aluminum alloy profile has a finer structure, higher strength and excellent ductility can be obtained.

[0011] The aluminum alloy profile according to the present invention preferably contains 0.4 to 0.8 mass% Mg, 0.2 to 0.9 mass% Si, 0.1 to 0.3 mass% Fe, and the balance being Al and unavoidable impurities, and in this case, an A6000 series aluminum alloy profile having high strength and excellent ductility can be obtained.

[0012] The manufacturing method of the aluminum alloy profile according to the present invention comprises manufacturing an aluminum alloy billet by an additive manufacturing method, and extruding the aluminum alloy billet to obtain a product having an average grain size of 10 μm or less in a cross section perpendicular to the extrusion direction, <001> More than 10% of grains are oriented in this direction. <112> The method is characterized by the production of aluminum alloy extrusions with 50% or more of crystal grains in the desired orientation.

[0013] The manufacturing method of the aluminum alloy profile according to the present invention can suitably manufacture the aluminum alloy profile according to the present invention. The manufacturing method of the aluminum alloy profile according to the present invention manufactures an aluminum alloy billet by additive manufacturing and extrudes the aluminum alloy billet, thereby manufacturing an aluminum alloy profile having a fine and dense structure and having high strength and excellent ductility compared to conventional extruded profiles manufactured by casting methods.

[0014] In the method for producing an aluminum alloy shaped material according to the present invention, it is preferable to use aluminum alloy powder as a material for the additive manufacturing method, and it is preferable that the additive manufacturing method uses a laser or an electron beam to melt and sinter the aluminum alloy powder to produce an aluminum alloy billet. Effect of the Invention

[0015] According to the present invention, it is possible to provide an aluminum alloy extrusion having a fine and dense structure as well as high strength and excellent ductility, and a method for producing the same. [Brief description of the drawings]

[0016] [Figure 1] 1 is a graph showing the relationship between energy density and billet density when an aluminum alloy billet is manufactured by an additive manufacturing method, in a manufacturing method of an aluminum alloy shaped material according to an embodiment of the present invention. [Diagram 2] 1A is an end view, FIG. 1B is a front view, FIG. 1C is a right side view, and FIG. 1D is an X-ray CT image showing a cavity (cast cavity) in an aluminum alloy billet manufactured by an additive manufacturing method, which is a manufacturing method for an aluminum alloy extrusion according to an embodiment of the present invention. [Diagram 3] FIG. 1A is a micrograph of a longitudinal section of an aluminum alloy billet of a test sample manufactured by an additive manufacturing method according to an embodiment of the present invention, after etching; and FIG. 1B is a micrograph of a longitudinal section of an aluminum alloy billet of a comparative sample manufactured by a casting method, after etching. [Figure 4]FIG. 1 shows the results of crystal orientation analysis using the EBSD method for an aluminum alloy extrusion manufacturing method according to an embodiment of the present invention, including (a) an oblique view showing an observation point of an aluminum alloy billet of a test sample manufactured by additive manufacturing, (b) an inverse pole figure orientation map (IPF map; shown in black and white) at the outer periphery of the longitudinal section, (c) a KAM (local orientation mismatch) map (shown in black and white), (d) an inverse pole figure orientation map (IPF map; shown in black and white) at the center of the longitudinal section, and (e) a KAM (local orientation mismatch) map (shown in black and white). [Diagram 5] FIG. 1 shows the results of crystal orientation analysis using the EBSD method for an aluminum alloy profile manufacturing method according to an embodiment of the present invention, including (a) an oblique view showing an observation point of an aluminum alloy billet of a test sample manufactured by an additive manufacturing method, (b) an inverse pole figure orientation map (IPF map; shown in black and white) at the outer periphery of the end face, (c) a KAM (local orientation misorientation) map (shown in black and white), (d) an inverse pole figure orientation map (IPF map; shown in black and white) at the center of the end face, and (e) a KAM (local orientation misorientation) map (shown in black and white). [Figure 6] FIG. 1 shows the results of crystal orientation analysis by EBSD method in a manufacturing method for an aluminum alloy profile according to an embodiment of the present invention, with (a) an inverse pole figure orientation map (IPF map; shown in black and white) and (b) an image quality map (IQ map) of a cross section perpendicular to the extrusion direction (ED cross section) of a comparative sample aluminum alloy profile (extrusion profile) manufactured by a casting method. [Figure 7] FIG. 1 shows the results of crystal orientation analysis by EBSD method in a manufacturing method for an aluminum alloy profile according to an embodiment of the present invention, with (a) an inverse pole figure orientation map (IPF map; shown in black and white) and (b) an image quality map (IQ map) of a longitudinal section (TD section) perpendicular to the plate width direction of a comparative sample aluminum alloy profile (extruded profile) manufactured by a casting method. [Figure 8] FIG. 1 shows the results of crystal orientation analysis using the EBSD method in a manufacturing method for an aluminum alloy profile according to an embodiment of the present invention, in which (a) is an inverse pole figure orientation map (IPF map; shown in black and white) of a cross section perpendicular to the extrusion direction (ED cross section) of an aluminum alloy profile (extrusion profile) of a test sample manufactured by an additive manufacturing method, and (b) is an enlarged map of a portion of (a). [Figure 9] FIG. 1 shows the results of crystal orientation analysis by EBSD method in a manufacturing method for an aluminum alloy profile according to an embodiment of the present invention, in which (a) is an inverse pole figure orientation map (IPF map; shown in black and white) of a cross section perpendicular to the plate width direction (TD cross section) of an aluminum alloy profile (extrusion profile) of a test sample manufactured by additive manufacturing, and (b) is an enlarged map of a portion of (a). [Figure 10] FIG. 1 shows (a) an inverse pole figure orientation map (IPF map; shown in black and white) of a cross section perpendicular to the extrusion direction (ED cross section) illustrating the results of crystal orientation analysis by the EBSD method of a test sample aluminum alloy shape (extrusion shape) manufactured by additive manufacturing, in a manufacturing method for an aluminum alloy shape according to an embodiment of the present invention, and (b) a graph showing the grain size distribution of the crystal grains in (a). [Figure 11] FIG. 1 shows (a) a crystal orientation map (shown in black and white) of a cross section perpendicular to the extrusion direction (ED cross section) showing the results of crystal orientation analysis by the EBSD method, of an aluminum alloy test sample (extruded profile) manufactured by additive manufacturing, a manufacturing method for an aluminum alloy profile according to an embodiment of the present invention, and (b) an inverse pole figure of

[0001] (shown in black and white). [Figure 12] FIG. 1 shows the results of crystal orientation analysis by the EBSD method of an aluminum alloy extrusion test sample manufactured by additive manufacturing in a manufacturing method for an aluminum alloy extrusion according to an embodiment of the present invention, in which (a) is an inverse pole figure orientation map (IPF map; shown in black and white) of a cross section perpendicular to the plate width direction (TD cross section), (b) is an aspect ratio map of crystal grains (shown in black and white), and (c) is a graph showing the distribution of aspect ratios of crystal grains in (b). [Figure 13] 1 is a graph showing the Vickers hardness of aluminum alloy extrusions (extrusions) of test samples manufactured by additive manufacturing and comparative samples manufactured by casting, in a manufacturing method of an aluminum alloy extrusion according to an embodiment of the present invention. [Figure 14]1A is a graph showing (a) the stress-strain curve, and (b) the tensile strength and 0.2% yield strength of an aluminum alloy extrusion material (extrusion material) of a test sample manufactured by an additive manufacturing method and a comparative sample manufactured by a casting method, in a manufacturing method of an aluminum alloy extrusion material according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, the embodiment of the present invention will be described based on examples. The aluminum alloy extrusion material according to the embodiment of the present invention is an A6000 series aluminum alloy extrusion material manufactured by extrusion processing, and contains 0.4 mass% to 0.8 mass% Mg, 0.2 mass% to 0.9 mass% Si, 0.1 mass% to 0.3 mass% Fe, and the balance being Al and unavoidable impurities.

[0018] In the aluminum alloy extrusion of the present invention, the average grain size of the grains is 10 μm or less in a cross section perpendicular to the extrusion direction, and among all the grains, <001> More than 10% of grains are oriented in this direction. <112> The crystal grains are oriented in the direction of extrusion at 50% or more. The crystal grains have a structure in which they form elongated fibers along the extrusion direction, and the average aspect ratio of the crystal grains is 0.5 or less. The aspect ratio of the crystal grains is the length of the crystal grains in the direction perpendicular to the extrusion direction relative to their length in the extrusion direction (hereinafter the same).

[0019] The aluminum alloy shaped material according to the embodiment of the present invention is suitably manufactured by the manufacturing method of the aluminum alloy shaped material according to the embodiment of the present invention. In the manufacturing method of the aluminum alloy shaped material according to the embodiment of the present invention, first, an aluminum alloy billet is manufactured by melting and sintering aluminum alloy powder as a material by an additive manufacturing method using a laser or an electron beam. Then, the manufactured aluminum alloy billet is extruded to manufacture the aluminum alloy shaped material according to the embodiment of the present invention.

[0020] In the manufacturing method of an aluminum alloy profile according to an embodiment of the present invention, an aluminum alloy billet is manufactured by an additive manufacturing method, and the aluminum alloy billet is extruded to manufacture an aluminum alloy profile having a finer and denser structure than a conventional extrusion using a billet manufactured by a casting method. Therefore, the manufactured aluminum alloy profile has higher strength and better ductility than a conventional extrusion using a casting method, according to the Hall-Petch relationship. EXAMPLES

[0021] An aluminum alloy shaped material was manufactured by the manufacturing method of an aluminum alloy shaped material according to the embodiment of the present invention. First, an aluminum alloy powder of A6063 was used as a raw material, and an aluminum alloy billet was manufactured by additive manufacturing in an Ar atmosphere using a commercially available metal 3D printer of the laser type (L-PBF; Laser Powder Bed Fusion). The average particle size (D50) of the raw aluminum alloy powder was 43.83 μm. In the additive manufacturing method, the layer thickness was set to 30 μm. In the additive manufacturing method, billets were manufactured at various energy densities as shown in FIG. 1, and the one with the highest density of the additively manufactured body was adopted as the test sample. The density of the adopted test sample was 99.9%, and the energy density during manufacturing was 166.67 J / mm 3 It is.

[0022] The aluminum alloy billet of the test sample produced had a cylindrical shape with an end face diameter of 42 mm and a height of 50 mm, and two of these were joined in the height direction to make a billet with a height of 100 mm. As shown in Table 1, the composition of the aluminum alloy billet included 0.43 mass% Mg, 0.51 mass% Si, 0.17 mass% Fe, and the balance was Al and unavoidable impurities.

[0023] [Table 1]

[0024] As a comparative sample, an aluminum alloy billet was manufactured by hot top casting using A6063 aluminum alloy as a raw material. The manufactured aluminum alloy billet of the comparative sample was cylindrical, with an end face diameter of 42 mm and a height of 100 mm. The composition of the aluminum alloy billet of the comparative sample included 0.47 mass% Mg, 0.48 mass% Si, 0.16 mass% Fe, and the balance being Al and unavoidable impurities.

[0025] The external appearance and X-ray CT images of the aluminum alloy billet of the test sample are shown in Figure 2(a) to (d). The dots and lines shown in Figure 2(a) to (d) represent cavities (cast holes), and it was confirmed that there were many cavities inside the billet.

[0026] Micrographs of the longitudinal sections of the aluminum alloy billets of the test sample and the comparative sample are shown in Figures 3(a) and (b), respectively. As shown in Figure 3(a), stripes with a width of approximately 10 μm or less were observed along the stacking direction (the "build direction" in the figure) in the test sample, and these stripes are thought to represent crystal grains. In contrast, as shown in Figure 3(b), no stripes were observed in the comparative sample, and it was confirmed that the grain size of the crystal grains was approximately 100 μm.

[0027] A crystal orientation analysis was performed on the aluminum alloy billet test sample using the EBSD method. An OIM crystal orientation analyzer manufactured by TSL Solutions, Inc. was used for the crystal orientation analysis. Figure 4 shows the inverse pole figure orientation map (IPF map) and KAM (local misorientation) map of the outer periphery and center of the longitudinal section of the test sample. Figure 5 shows the inverse pole figure orientation map (IPF map) and KAM (local misorientation) map of the outer periphery and center of the end face of the test sample.

[0028] As shown in Figure 4, in the longitudinal section, a pattern extending along the lamination direction was observed in both the outer periphery and the center. Also, as shown in Figures 4 and 5, the aluminum alloy billet of the test sample had a crystal orientation of <100> and <110> It was also confirmed that the KAM value of the aluminum alloy billet of the test sample was obviously larger than the KAM value of the aluminum alloy billet of the comparative sample (not shown), as shown in Figures 4 and 5.

[0029] Next, the aluminum alloy billets of the test sample and the comparative sample were extruded to produce aluminum alloy shapes (hereinafter also referred to as "extruded shapes"). In the extrusion process, a 200 t extruder was used, the extrusion pressure was 68 t, the heating temperature of the die and billet was 480°C, the heating time of the die and billet was about 2 hours, the ram speed was 5 mm / s, and the cooling after processing was water-cooled. Each extruded shape was elongated along the extrusion direction, forming a rectangular plate shape with a length of about 2 m, a width of 25 mm, and a thickness of 2 mm.

[0030] Crystal orientation analysis was performed on the extruded shapes of the comparative sample and the test sample using the EBSD method. For the crystal orientation analysis, an OIM crystal orientation analyzer manufactured by TSL Solutions, Inc. was used. Figure 6 shows the inverse pole figure orientation map (IPF map) and image quality map (IQ map) of the cross section (ED cross section) perpendicular to the extrusion direction (ED direction) of the extruded shape of the comparative sample, and Figure 7 shows the inverse pole figure orientation map (IPF map) and image quality map (IQ map) of the longitudinal cross section (TD cross section) perpendicular to the plate width direction (TD direction) of the extruded shape of the test sample. Figures 8 and 9 show the inverse pole figure orientation map (IPF map) of the cross section (ED cross section) perpendicular to the extrusion direction and the longitudinal cross section (TD cross section) perpendicular to the plate width direction, respectively, of the extruded shape of the test sample.

[0031] As shown in Figures 6 and 7, the extruded specimen of the comparative sample had internal grains. <100> It was confirmed that the extruded shape of the test sample had a grain size of 10 μm or less and a structure in which the crystal grains were elongated and fibrous along the extrusion direction, with a dominant orientation of 10 μm to 100 μm. In contrast, as shown in Figures 8 and 9, it was confirmed that the extruded shape of the test sample had a grain size of 10 μm or less and a structure in which the crystal grains were elongated and fibrous along the extrusion direction.

[0032] The grain size distribution in the ED cross section of the extruded test specimen was investigated and is shown in Figure 10. As shown in Figure 10, it was confirmed that the average grain size was approximately 2.8 μm, the percentage of grains with a grain size of 5 μm or less was 80.0%, and the percentage of grains with a grain size of 10 μm or less was 96.8%. Thus, it was confirmed that the grains of the extruded test specimen were finer than those of the extruded comparative specimen.

[0033] The crystal direction map and the inverse pole figure of

[0001] in the ED cross section of the extruded specimen of the test sample are shown in Figure 11. As shown in Figure 11, within the range of ±10 degrees fluctuation, <001> More than 10% of grains are oriented in this direction. <112> It was confirmed that the grains of the orientation were more than 50%.

[0034] The grain shape aspect ratio map and aspect ratio distribution in the TD cross section of the extruded test specimen are shown in Figure 12. As shown in Figure 12, it was confirmed that the average grain aspect ratio was 0.42, the proportion of grains with an aspect ratio of 0.5 or less was 63.9%, and the proportion of grains with an aspect ratio of 0.65 or less was 92.6%.

[0035] The Vickers hardness of the extruded shapes of the test sample and the comparative sample was measured, and the results are shown in Figure 13. As shown in Figure 13, it was confirmed that the Vickers hardness of the extruded shape of the test sample was approximately 20% higher than that of the extruded shape of the comparative sample.

[0036] Tensile tests were conducted on the extruded profiles of the test sample and the comparative sample. The tensile tests were conducted in accordance with JIS Z 2241 using a commercially available testing device (Instron 5982). The stress-strain curves in the tensile tests are shown in Fig. 14(a), and the tensile strength and 0.2% yield strength obtained by the tensile tests are shown in Fig. 14(b). As shown in Fig. 14, it was confirmed that the tensile strength of the extruded profile of the test sample was approximately 20% higher than that of the extruded profile of the comparative sample. It was also confirmed that the yield strength of the extruded profile of the test sample was approximately 30% higher than that of the extruded profile of the comparative sample. It was also confirmed that the ductility (elongation at break) of the extruded profile of the test sample was 43% higher than that of the extruded profile of the comparative sample.

Claims

1. An aluminum alloy profile manufactured by extrusion processing, In a cross section perpendicular to the extrusion direction, the average grain size of the grains is 10 μm or less, the grains with the <001> orientation are 10% or more, and the grains with the <112> orientation are 50% or more. Aluminium alloy profiles.

2. 2. The aluminum alloy extrusion according to claim 1, characterized in that the crystal grains have a structure in which they are elongated and fibrous along the extrusion direction, and the aspect ratio of the crystal grains, defined as the ratio of the length of the crystal grains in the extrusion direction to the length of the crystal grains in the extrusion direction in a direction perpendicular to the extrusion direction, is an average of 0.5 or less.

3. 3. The aluminum alloy profile according to claim 2, characterized in that the aluminum alloy profile has a rectangular plate shape that is elongated in the extrusion direction, and in a cross section perpendicular to the plate width direction, the proportion of crystal grains having an aspect ratio of 0.5 or less is 50% or more, and the proportion of crystal grains having an aspect ratio of 0.65 or less is 90% or more.

4. 2. The aluminum alloy shape according to claim 1, wherein the average grain size of the grains is 5 μm or less.

5. 5. The aluminum alloy shape according to claim 4, wherein the proportion of crystal grains having a grain size of 5 μm or less is 70% or more, and the proportion of crystal grains having a grain size of 10 μm or less is 90% or more.

6. 6. The aluminum alloy shape according to claim 1, characterized in that it contains 0.4 mass% to 0.8 mass% Mg, 0.2 mass% to 0.9 mass% Si, 0.1 mass% to 0.3 mass% Fe, and the balance consisting of Al and unavoidable impurities.

7. A method for producing an aluminum alloy profile, comprising the steps of: producing an aluminum alloy billet by an additive manufacturing method; and extruding the aluminum alloy billet to produce an aluminum alloy profile having, in a cross section perpendicular to the extrusion direction, an average crystal grain size of 10 μm or less, 10% or more of crystal grains having a <001> orientation, and 50% or more of crystal grains having a <112> orientation.

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