Aluminum alloy material, aluminum alloy structure, and manufacturing method for same

Abstract

Aluminum alloy material containing Si: 1.0 to 5.0 mass % and Fe: 0.01 to 2.0 mass % with balance being Al and inevitable impurities, wherein 250 pcs/mm.sup.2 or more to 710.sup.5 pcs/mm.sup.2 or less of Si-based intermetallic compound particles having equivalent circle diameters of 0.5 to 5 m are present in a cross-section of the aluminum alloy material, while 100 pcs/mm.sup.2 or more to 710.sup.5 pcs/mm.sup.2 or less of Al-based intermetallic compound particles having equivalent circle diameters of 0.5 to 5 m are present in a cross-section of the aluminum alloy material. An aluminum alloy structure is manufactured by bonding two or more members in vacuum or a non-oxidizing atmosphere at temperature at which a ratio of a mass of a liquid phase generated in the aluminum alloy material to a total mass of the aluminum alloy material is 5% or more and 35% or less.

Claims

1. A fin member for a heat exchanger having a heat bonding ability with a single layer comprising an aluminum alloy material consisting essentially of Si: 1.0 mass % to 5.0 mass % and Fe: 0.01 mass % to 2.0 mass %, at least one of Mg: in an amount of >0 and 2.0 mass %, Cu: in an amount of >0 and 1.5 mass %, and Mn: in an amount of >0 and 2.0 mass %, and at least one of Ti: in an amount of >0 and 0.3 mass %, V: in an amount of >0 and 0.3 mass %, Cr: in an amount of >0 and 0.3 mass %, Ni: in an amount of >0 and 2.0 mass %, and Zr: in an amount of >0 and 0.3 mass %, with balance being Al and inevitable impurities, wherein the contents (mass %) of Si, Fe and Mn are denoted by S, F, and M, respectively and a relational expression of 1.2S0.3(F+M)3.5 is satisfied, wherein 1.310.sup.3 pcs/mm.sup.2 or more to 2.210.sup.4 pcs/mm.sup.2 or less of Si-based intermetallic compound particles, each of which has equivalent circle diameters of 0.5 to 5 m and is selected from Si alone and Si partly containing elements of Ca and P, are present in a cross-section of the aluminum alloy material, wherein 1.310.sup.3 pcs/mm.sup.2 or more to 3.310.sup.4 pcs/mm.sup.2 or less of dispersed particles of Al-based intermetallic compounds, each of which has equivalent circle diameters of 0.5 to 5 m and is generated from Al and additive elements selected from AlFe-based, AlFeSi-based, AlMnSi-based, AlFeMn-based and AlFeMnSi-based compounds, are present in a cross-section of the aluminum alloy material, wherein the aluminum alloy material is heat bonded with a single layer without the use of a brazing filler metal, and wherein the fin is bonded to a second member, wherein, in a metal structure in a cross-section of at least one of the bonded members, 10 to 3000 pcs/mm.sup.2 of eutectic structures having a length of 3 m or more are present within matrix crystal grains.

2. The fin member according to claim 1, wherein in the metal structure in the cross-section of the at least one bonded members, a number of triple points of grain boundaries where Si-based intermetallic compounds and Al-based intermetallic compounds both having equivalent circle diameters of 1 m or more exist, is 50% or more of the number of triple points of all the grain boundaries.

Description

BRIEF DESCRIPTION OF THE INVENTION

(1) FIG. 1 illustrates a phase diagram of an AlSi alloy that is a binary eutectic alloy.

(2) FIGS. 2(A)-2(D) are explanatory views to explain a liquid phase generation mechanism in an aluminum alloy material according to the present invention, which is developed with a bonding method using the aluminum alloy material.

(3) FIGS. 3(A)-3(D) are explanatory views to explain a liquid phase generation mechanism in the aluminum alloy material according to the present invention, which is developed with the bonding method using the aluminum alloy material.

(4) FIG. 4 is a perspective view of a three-stage laminated test piece (mini-core) used in first to third embodiments.

(5) FIG. 5 is a perspective view illustrating a part of the shape of an extruded tube used in a test piece in the third embodiment.

(6) FIG. 6 is a diagram illustrating grain boundaries and a triple point thereof.

(7) FIG. 7 is an explanatory view illustrating a method for discriminating the triple point of the grain boundaries.

MODE FOR CARRYING OUT THE INVENTION

(8) The present invention will be described in detail below in connection with Inventive Examples and Comparative Examples.

First Embodiment

(9) Test plates made of aluminum alloy materials B1 to B59 and B77-B98 in Tables 3 to 5 were first manufactured using aluminum alloys having compositions listed in Tables 1 and 2. In the alloy compositions of Table 1, - represents that the content is not more than a detection limit, and balance includes inevitable impurities.

(10) The test plates of B1 to B48, B52 to B57, and B84 were each cast by the twin-roll continuous casing and rolling method. The temperature of a molten metal during the casting with the twin-roll continuous casing and rolling method was 650 to 800 C., and the thickness of each cast plate was 7 mm. The casting speed was variously changed as listed in Tables 3 to 5. The obtained plate-like ingot was cold-rolled to a thickness of 0.70 mm and, after intermediate annealing of 420 C.2 Hr, it was further cold-rolled to a thickness of 0.050 mm, whereby a sample plate was obtained. The arithmetic mean waviness Wa of the sample plate was about 0.5 m.

(11) The test plates of B49-B51, B58-B59, B77-B83, and B85-B98 were each cast in size of 100 mm300 mm by the DC casting method. The casting speed was variously changed as listed in Tables 4 and 5. After facing each of cast slabs, the slab was heated and hot-rolled to a thickness of 3 mm. Then, the hot-rolled plate was cold-rolled to a thickness of 0.070 mm and, after intermediate annealing of 380 C.2 Hr, it was further cold-rolled to a thickness of 0.050 mm, whereby a sample plate was obtained. The arithmetic mean waviness Wa of the sample plate was about 0.5 m.

(12) The above-mentioned test plates were evaluated for manufacturability in the manufacturing process. The manufacturability was evaluated by a method of, in manufacturing each plate or slab, rating the test plate to be when the sound plate or slab was obtained without causing any problems during the manufacturing process, and rating the test plate to be x when any problem occurred during the manufacturing process, such as the occurrence of cracking during the casting, or a difficulty in continuing the rolling due to generation of giant intermetallic compounds during the casting.

(13) The surface density of the intermetallic compounds in the manufactured plate (material plate) was measured with SEM observation (observation of a reflected electron image) of a cross-section of the plate taken in the direction of plate thickness. The Si-based intermetallic compounds and the Al-based intermetallic compounds (AlFe-based intermetallic compounds and etc.) were discriminated based on the difference in contrast with the SEM observation. The SEM observation was performed on five viewing fields for each sample, and the density of the dispersed particles having the equivalent circle diameters of 0.5 m to 5 m in the sample was measured through an image analysis of an SEM photo in each viewing field.

(14) Tables 3 to 5 list the results of evaluating the manufacturability and measuring the dispersed particles. As listed in Tables 3 to 5, the manufacturability was good when the compositions of the aluminum alloy materials were within the ranges specified in the present invention. In the case of the alloy composition A68, because Fe exceeded the specified amount, giant intermetallic compounds were generated during the casting, and the rolling could not be continued until reaching the final plate thickness. Thus, a problem occurred in manufacturability. In the case of the alloy composition A70, because Ni exceeded the specified amount, giant intermetallic compounds were generated during the casting, and a problem occurred in manufacturability. In the case of the alloy composition A71, because Ti exceeded the specified amount, giant intermetallic compounds were generated during the casting, and the rolling could not be continued until reaching the final plate thickness. Thus, a problem occurred in manufacturability. In the cases of the alloy compositions A89-92, because Mn, V, Cr and Zr exceeded the respective specified amounts, giant intermetallic compounds were generated during the casting, and the rolling could not be continued until reaching the final plate thickness. Thus, a problem occurred in manufacturability.

(15) Next, as illustrated in FIG. 4, each test plate was formed into a fin member having a width of 16 mm, a crest height of 7 mm, and a pitch of 2.5 mm. Furthermore, a material plate having the composition b1 (Table 2) was formed into an electrically-welded tube member having an arithmetic mean waviness Wa of 0.3 m and a plate thickness of 0.4 mm. A three-stage laminated test piece (mini-core), illustrated in FIG. 4, was fabricated by combining the obtained fin and tube members with each other, and assembling them with the aid of a stainless jig. The test pieces (mini-cores) fabricated using the fin and tube members, which are made of each of the test plates (B1-B59 and B77-B98), are listed respectively as C1-C59 and C77-C98 in Tables 3 to 5.

(16) Next, the above-mentioned mini-cores were each dipped in a suspension solution containing 10% of non-corrosive fluoride-based flux. After drying, the mini-core was heated for 3 minutes at 580 to 600 C. in a nitrogen atmosphere, thereby bonding the fin and tube members to each other. In the case of the mini-core thus obtained, because of the difference in coefficient of thermal expansion between the stainless jig and the aluminum material, a compression load of about 4N was generated between the stainless jig and the mini-core during the heating for the bonding. This implies that, with calculation based on a bonding area, stress of about 10 kPa is generated at the bonding interface between the fin and the tube.

(17) After bonding the fin and tube members to each other, the fin was peeled from the tube, and a bonding state was examined at 40 bonding portions between the tube and the fin, thereby determining a rate (bonding rate) of completely-bonded portions. A buckling state of the fin was also examined. The fin buckling was determined to be when a rate of change in the fin height between before and after the bonding with respect to the fin height before the bonding was 5% or less, when it was more than 5% and 10% or less, when it was more than 10% and 15% or less, and x when it was more than 15%.

(18) Furthermore, the mini-core after the bonding was embedded in a resin. After grinding, the surface density of the eutectic structures within the grains, having lengths of 3 m or more, was measured by observing the structure in a cross-section of the member with an optical microscope. Moreover, the cross-section of the mini-core after the bonding was ground and etched using the Keller's reagent, for example, and the positions of the intermetallic compounds were identified. In addition, the grain boundaries in the relevant cross-section were made clear by the anodic oxidation method, and the positions of the triple points of the grain boundaries were identified. By comparing the positions of the intermetallic compounds and the positions of the triple points of the grain boundaries, a rate of the triple points of the grain boundaries where the intermetallic compounds existed was determined.

(19) The evaluation results of the mini-core bonding test described above are listed in Tables 3 to 5. Tables 3 to 5 further list an equilibrium liquid phase rate at the heating temperature for each sample. The equilibrium liquid phase rate is a calculated value obtained by employing the equilibrium phase-diagram calculation software.

(20) TABLE-US-00001 TABLE 1 Com- position Alloy Composition (mass %) No. Si Fe Cu Mn Mg Zn Ni Ti V Cr Zr Be Sr Bi Na Ca Al A3 2.1 0.05 balance A5 3.4 0.05 balance A7 2.5 0.08 balance A8 2.5 0.12 balance A9 2.5 0.23 balance A10 2.5 0.90 balance A11 2.5 1.80 balance A25 2.1 0.12 balance A26 3.4 1.80 balance A27 4.8 0.12 balance A28 2.5 0.25 0.08 balance A29 2.5 0.25 0.12 balance A30 2.5 0.25 0.32 balance A31 2.5 0.25 1.10 balance A32 2.5 0.25 1.40 balance A33 2.5 0.25 1.90 balance A34 2.5 0.25 0.08 balance A35 2.5 0.25 0.12 balance A36 2.5 0.25 0.22 balance A37 2.5 0.25 0.80 balance A38 2.5 0.25 1.40 balance A39 2.5 0.25 0.05 balance A40 2.5 0.25 0.15 balance A41 2.5 0.25 0.40 balance A42 2.5 0.25 0.70 balance A43 2.5 0.25 0.08 balance A44 2.5 0.25 0.12 balance A45 2.5 0.25 1.10 0.50 balance A46 2.5 0.25 1.10 1.20 balance A47 2.5 0.25 1.10 2.00 balance A48 2.5 0.25 1.10 5.50 balance

(21) TABLE-US-00002 TABLE 2 Com- position Alloy Composition (mass %) No. Si Fe Cu Mn Mg Zn Ni Ti V Cr Zr Be Sr Bi Na Ca Al A50 2.5 0.25 0.08 balance A51 2.5 0.25 0.12 balance A52 2.5 0.25 0.23 balance A53 2.5 0.25 0.80 balance A54 2.5 0.25 1.80 balance A56 2.5 0.75 1.00 balance A57 1.5 0.25 0.30 0.60 0.12 balance A58 2.5 0.25 0.12 0.13 0.50 0.07 0.07 balance A59 2.5 0.25 1.48 0.50 0.28 0.28 balance A60 2.5 0.25 1.80 2.50 balance A61 2.5 0.25 1.80 0.05 0.01 balance A62 2.5 0.25 5.00 0.30 balance A63 2.5 0.25 0.30 0.01 0.01 0.01 balance A64 2.5 0.25 1.10 0.10 0.10 0.10 0.02 0.01 balance A65 2.5 0.25 1.80 0.10 0.001 0.001 balance A74 2.5 0.25 0.05 balance A75 2.5 0.25 0.07 balance A76 2.5 0.25 0.10 balance A77 2.5 0.25 0.18 balance A78 2.5 0.25 0.25 balance A79 2.5 0.25 1.10 0.15 balance A80 1.9 0.80 0.80 balance A81 2.5 0.25 0.20 balance A82 2.5 0.25 0.10 0.10 balance A83 2.5 0.25 0.15 0.15 balance A84 2.5 0.25 0.18 0.18 balance A85 2.5 0.25 0.10 balance A86 2.5 0.25 0.15 balance A87 2.5 0.25 0.18 balance A66 0.9 0.25 balance A67 5.3 0.25 balance A68 2.5 2.50 1.50 balance A69 2.5 0.25 2.20 balance A70 2.5 0.25 2.20 balance A71 2.5 0.25 0.32 balance A72 2.5 0.25 0.15 0.15 0.15 balance A73 2.5 0.25 0.15 0.06 balance A88 2.5 0.005 balance A89 2.5 0.25 2.20 balance A90 2.5 0.25 0.33 balance A91 2.5 0.25 0.33 balance A92 2.5 0.25 0.33 balance b1 0.5 0.30 0.15 1.0 balance

(22) TABLE-US-00003 TABLE 3 Bonding Compo- Casting Conditions Bonding Sample Material sition Casting Speed Temp. Rate Fin No. No. No. Method (m/min) (c) (d) (e) ( C.) (f) (g) (h) (%) Buckling (a) C1 B1 A3 (b) 1.0 1.3E+04 4.8E+03 600 12 2.9E+03 70 92.1 C2 B2 A5 (b) 1.0 1.7E+04 4.8E+03 600 27 1.3E+03 86 100.0 C3 B3 A7 (b) 1.0 1.4E+04 6.0E+03 600 17 2.0E+03 76 95.6 C4 B4 A8 (b) 1.1 1.5E+04 7.6E+03 600 17 1.8E+03 76 95.8 C5 B5 A9 (b) 1.0 1.4E+04 1.0E+04 600 18 1.3E+03 77 96.0 C6 B6 A10 (b) 1.0 1.3E+04 2.0E+04 600 14 3.7E+02 73 93.8 C7 B7 A11 (b) 1.0 1.2E+04 2.7E+04 600 9 7.6E+01 65 88.9 C8 B8 A25 (b) 1.0 1.3E+04 7.3E+03 600 12 2.6E+03 71 92.5 C9 B9 A26 (b) 1.5 2.0E+04 3.3E+04 600 27 2.4E+01 87 100.0 C10 B10 A27 (b) 1.0 2.2E+04 7.3E+03 580 31 9.9E+02 91 100.0 C11 B11 A28 (b) 1.0 1.4E+04 1.2E+04 600 18 1.1E+03 76 95.5 C12 B12 A29 (b) 1.0 1.4E+04 1.3E+04 600 18 1.0E+03 76 95.5 C13 B13 A30 (b) 1.0 1.4E+04 1.6E+04 600 16 6.7E+02 75 94.9 C14 B14 A31 (b) 1.0 1.3E+04 2.4E+04 600 14 1.3E+02 72 93.1 C15 B15 A32 (b) 1.0 1.2E+04 2.6E+04 600 13 7.1E+01 71 92.5 C16 B16 A33 (b) 1.0 1.2E+04 3.0E+04 600 11 2.6E+01 70 91.7 C17 B17 A34 (b) 1.0 1.4E+04 1.0E+04 600 19 1.2E+03 77 96.0 C18 B18 A35 (b) 1.0 1.4E+04 1.0E+04 600 19 1.2E+03 77 96.0 C19 B19 A36 (b) 1.0 1.4E+04 1.0E+04 600 19 1.2E+03 78 96.5 C20 B20 A37 (b) 1.0 1.4E+04 1.0E+04 600 23 1.0E+03 80 98.0 C21 B21 A38 (b) 1.0 1.4E+04 1.0E+04 600 26 8.9E+02 83 99.5 C22 B22 A39 (b) 1.0 1.4E+04 1.0E+04 600 19 1.2E+03 77 96.0 C23 B23 A40 (b) 1.0 1.4E+04 1.0E+04 600 19 1.2E+03 78 96.5 C24 B24 A41 (b) 1.0 1.4E+04 1.0E+04 600 21 1.1E+03 78 97.0 C25 B25 A42 (b) 1.0 1.4E+04 1.0E+04 600 23 1.0E+03 80 98.0 C26 B26 A43 (b) 1.0 1.4E+04 1.0E+04 600 18 1.3E+03 77 96.0 C27 B27 A44 (b) 1.0 1.4E+04 1.0E+04 600 18 1.3E+03 77 96.0 C28 B28 A45 (b) 1.0 1.3E+04 2.4E+04 600 15 1.2E+02 73 93.6 C29 B29 A46 (b) 1.0 1.3E+04 2.4E+04 600 16 1.1E+02 74 94.1 C30 B30 A47 (b) 1.0 1.3E+04 2.4E+04 600 17 1.0E+02 75 95.1 C31 B31 A48 (b) 1.0 1.3E+04 2.4E+04 600 26 7.2E+01 82 99.1 (a) Inventive Example (b) Continuous casting (c) Manufacturability (d) Surface Density of Si-based Intermetallic Compounds (number/mm.sup.2) (e) Surface Density of Al-based Intermetallic Compounds (number/mm.sup.2) (f) Equilibrium Liquid Phase Rate (%) (g) Surface Density of Eutectic Structures (number/mm.sup.2) (h) Rate of Triple Points of Grain boundaries where Intermetallic Compounds Exist (%) E+ in Table indicates exponential notation. For example, 1.3+04 implies 1.3 10.sup.4.

(23) TABLE-US-00004 TABLE 4 Bonding Compo- Casting Conditions Bonding Sample Material sition Casting Speed Temp. Rate Fin No. No. No. Method (m/min) (c) (d) (e) ( C.) (f) (g) (h) (%) Buckling (a) C33 B33 A50 (b) 1.0 1.4E+04 1.0E+04 600 19 1.2E+03 77 96.0 C34 B34 A51 (b) 1.0 1.4E+04 1.0E+04 600 19 1.2E+03 77 96.0 C35 B35 A52 (b) 1.0 1.4E+04 1.0E+04 600 20 1.2E+03 78 96.5 C36 B36 A53 (b) 1.0 1.4E+04 1.0E+04 600 23 1.0E+03 80 98.0 C37 B37 A54 (b) 1.0 1.4E+04 1.0E+04 600 27 8.7E+02 83 100.0 C39 B39 A56 (b) 1.0 1.4E+04 1.8E+04 600 17 4.3E+02 75 94.8 C40 B40 A57 (b) 0.8 8.0E+03 1.7E+04 600 18 3.2E+02 72 93.0 C41 B41 A58 (b) 0.8 1.2E+04 1.1E+04 600 21 8.0E+02 78 96.8 C42 B42 A59 (b) 0.8 1.2E+04 9.4E+03 600 27 8.4E+02 83 99.9 C43 B43 A60 (b) 0.8 1.0E+04 2.6E+04 600 16 2.3E+01 72 93.2 C44 B44 A61 (b) 1.2 1.6E+04 1.1E+04 600 27 8.7E+02 84 100.0 C45 B45 A62 (b) 0.6 1.0E+04 8.1E+03 600 29 8.0E+02 83 99.6 C46 B46 A63 (b) 0.6 1.0E+04 8.1E+03 600 17 1.4E+03 73 93.6 C47 B47 A64 (b) 0.6 9.3E+03 1.9E+04 600 14 1.3E+02 70 91.7 C48 B48 A65 (b) 0.6 1.0E+04 8.1E+03 600 30 7.7E+02 84 100.0 C49 B49 A25 DC 0.03 1.3E+03 1.3E+03 600 12 2.6E+03 55 82.8 casting C50 B50 A60 DC 0.04 1.5E+03 6.1E+03 600 16 2.3E+01 58 84.8 casting C51 B51 A64 DC 0.03 1.4E+03 4.3E+03 600 14 1.3E+02 56 83.3 casting C77 B77 A74 DC 0.03 1.5E+03 1.9E+03 600 17 1.4E+03 60 85.7 casting C78 B78 A75 DC 0.03 1.5E+03 1.9E+03 600 17 1.4E+03 60 85.7 casting C79 B79 A76 DC 0.03 1.5E+03 1.9E+03 600 16 1.4E+03 59 85.2 casting C80 B80 A77 DC 0.03 1.5E+03 1.9E+03 600 17 1.4E+03 60 85.7 casting C81 B81 A78 DC 0.03 1.5E+03 1.9E+03 600 16 1.4E+03 59 85.2 casting C82 B82 A79 DC 0.03 1.4E+03 4.3E+03 600 17 1.1E+02 59 85.3 casting C83 B83 A80 DC 0.05 1.5E+03 6.7E+03 610 10 4.1E+01 54 82.2 casting C84 B84 A80 (b) 1 1.0E+04 2.9E+04 610 10 4.1E+01 68 90.5 C85 B85 A81 DC 0.03 1.5E+03 1.9E+03 600 19 1.2E+03 61 86.7 casting C86 B86 A82 DC 0.03 1.5E+03 1.9E+03 600 17 1.4E+03 60 85.7 casting C87 B87 A83 DC 0.03 1.5E+03 1.9E+03 600 17 1.4E+03 60 85.7 casting C88 B88 A84 DC 0.03 1.5E+03 1.9E+03 600 17 1.4E+03 60 85.7 casting C89 B89 A85 DC 0.03 1.5E+03 1.9E+03 600 17 1.4E+03 60 85.7 casting C90 B90 A86 DC 0.03 1.5E+03 1.9E+03 600 17 1.4E+03 60 85.7 casting C91 B91 A87 DC 0.03 1.5E+03 1.9E+03 600 17 1.4E+03 60 85.7 casting (a) Inventive Example (b) Continuous casting (c) Manufacturability (d) Surface Density of Si-based Intermetallic Compounds (number/mm.sup.2) (e) Surface Density of Al-based Intermetallic Compounds (number/mm.sup.2) (f) Equilibrium Liquid Phase Rate (%) (g) Surface Density of Eutectic Structures (number/mm.sup.2) (h) Rate of Triple Points of Grain boundaries where Intermetallic Compounds Exist (%) E+ in Table indicates exponential notation. For example, 1.3+04 implies 1.3 10.sup.4.

(24) TABLE-US-00005 TABLE 5 Bonding Compo- Casting Conditions Bonding Sample Material sition Casting Speed Temp. Rate Fin No. No. No. Method (m/min) (c) (d) (e) ( C.) (f) (g) (h) (%) Buckling (i) C52 B52 A66 (b) 1.0 7.1E+03 1.0E+04 620 4 5.8E+03 48 73.4 C53 B53 A67 (b) 1.0 2.3E+04 1.0E+04 580 36 6.3E+02 95 100.0 X C54 B54 A68 (b) 1.0 X 8.5E+03 4.4E+04 C55 B55 A69 (b) 1.0 1.4E+04 1.0E+04 600 32 7.3E+02 88 30.0 C56 B56 A70 (b) 1.0 X 1.4E+04 1.0E+04 C57 B57 A71 (b) 0.2 X 5.0E+03 4.8E+03 C58 B58 A72 DC 0.3 6.5E+03 5.8E+03 600 18 1.3E+03 71 58.5 Casting C59 B59 A73 DC 0.3 6.5E+03 5.8E+03 600 18 1.3E+03 71 57.7 Casting C93 B93 A88 DC 0.003 3.5E+02 9.0E+01 600 17 2.4E+03 49 79.4 X Casting C94 B94 A80 DC 0.003 2.4E+02 1.7E+03 610 10 4.1E+01 41 74.4 Casting C95 B95 A89 DC 1.0 X 2.6E+03 1.0E+04 Casting C96 B96 A90 DC 1.0 X 3.2E+03 3.4E+03 Casting C97 B97 A91 DC 1.0 X 3.2E+03 3.4E+03 Casting C98 B98 A92 DC 1.0 X 3.2E+03 3.4E+03 Casting (i) Comparative Example (b) Continuous casting (c) Manufacturability (d) Surface Density of Si-based Intermetallic Compounds (number/mm.sup.2) (e) Surface Density of Al-based Intermetallic Compounds (number/mm.sup.2) (f) Equilibrium Liquid Phase Rate (%) (g) Surface Density of Eutectic Structures (number/mm.sup.2) (h) Rate of Triple Points of Grain boundaries where Intermetallic Compounds Exist (%) E+ in Table indicates exponential notation. For example, 1.3+04 implies 1.3 10.sup.4.

(25) As seen from comparing the evaluation results of the individual mini-core samples, listed in Tables 3 to 5, with the compositions (Tables 1 and 2) of the aluminum alloy materials of the fin members, the bonding rate and the fin buckling were both acceptable in the samples (C1-C51 and C77-C98), which satisfied the conditions specified in the present invention with regard to the composition of the aluminum alloy material and the heating condition.

(26) On the other hand, in Comparative Example C52 (alloy composition A66), because the Si component did not reach the specified amount, the liquid phase rate (equilibrium liquid phase rate) was as low as less than 5%, and the rate of the triple points of the grain boundaries where the intermetallic compounds existed was also low. As a result, the bonding rate was reduced, and the fin buckling could not be measured.

(27) In Comparative Example C53 (alloy composition A67), because the Si component exceeded the specified amount, the liquid phase rate was high during the bonding, and the fin was collapsed and buckled.

(28) In Comparative Example C54 (alloy composition A68), as described above, because the Fe component exceeded the specified amount, giant intermetallic compounds were generated, and the rolling could not be continued until reaching the final plate thickness. Thus, a problem occurred in manufacturability.

(29) In Comparative Example C55 (alloy composition A69), because Mg exceeded the specified amount, the bonding rate was as low as 30%, and the bonding was uncompleted.

(30) In Comparative Example C56 (alloy composition A70), as described above, a problem occurred in manufacturability. In Comparative Example C57 (alloy composition A71), as described above, giant intermetallic compounds were generated during the casting, and the rolling could not be continued until reaching the final plate thickness. Thus, a problem occurred in manufacturability.

(31) In Comparative Example C58 (alloy composition A72), because Be, Sr and Bi exceeded the respective specified amounts, an oxide film on the surface was thickened, and the bonding rate was reduced.

(32) In Comparative Example C59 (alloy composition A73), because Na and Ca exceeded the respective specified amounts, an oxide film on the surface was thickened, and the bonding rate was reduced.

(33) In Comparative Example C93 (alloy composition A88), because the Fe component was less than the specified amount, the surface density of the Al-based intermetallic compounds in the alloy was reduced, and the rate of the triple points of the grain boundaries where the intermetallic compounds existed was also low. As a result, the bonding rate was reduced, and the fin buckling occurred.

(34) In Comparative Example C94 (alloy composition A80), although the alloy composition was within the specified range, the surface density of the Si-based intermetallic compounds was reduced, and the rate of the triple points of the grain boundaries where the intermetallic compounds existed was also low. As a result, the bonding rate was reduced.

(35) In Comparative Examples C95-98 (alloy compositions A89-92), as described above, giant intermetallic compounds were generated during the casting, and the rolling could not be continued until reaching the final plate thickness. Thus, a problem occurred in manufacturability.

Second Embodiment

(36) In a second embodiment, influences of the heating temperature as one of the bonding conditions were examined. The material plates manufactured in the first embodiment were optionally selected as listed in Table 6 and were formed into fin members similar to those in the first embodiment. Furthermore, as in the first embodiment, three-stage laminated test pieces (mini-cores) were fabricated (FIG. 4). The mini-cores were each dipped in a suspension solution containing 10% of non-corrosive fluoride-based flux. After drying, the mini-cores were heated and held for predetermined times at various heating temperatures, listed in Table 6, in a nitrogen atmosphere, thereby bonding the fin and tube members to each other.

(37) For each of the mini-cores thus bonded, the bonding rate was measured and evaluated in the same way as in the first embodiment. Furthermore, the fin height of the mini-core after the bonding was measured, and a change rate of the size after the bonding with respect to that before the bonding was determined as a deformation rate. The evaluation result was determined to be when the deformation rate was 3% or less, when it was more than 3% and 5% or less, when it was more than 5% and 8% or less, and x when it was more than 8%. In addition, as in the first embodiment, the structure in a cross-section of each member was observed to determine the surface density of the intermetallic compounds, the surface density of the eutectic structures having lengths of 3 m or more within the grains, and the rate of the triple points of the grain boundaries where the intermetallic compounds having the equivalent circle diameters of 1 m or more existed with respect to the triple points of all the grain boundaries. The evaluation results are listed in Table 6.

(38) TABLE-US-00006 TABLE 6 Compo- Bonding Conditions Bonding Defor- Sample Material sition Temp. Holding Rate mation No. No. No. (d) (e) ( C.) (f) Time (T) (j) (k) (g) (h) (%) Rate (a) C61 B2 A5 1.7E+04 4.8E+03 580 18 180 577 200 2.0E+03 78 97 C62 B2 A5 1.7E+04 4.8E+03 600 27 180 577 330 1.4E+03 86 100 C63 B7 A11 1.2E+04 2.7E+04 600 9 180 590 245 7.2E+01 68 91 C64 B7 A11 1.2E+04 2.7E+04 620 30 180 590 375 2.2E+01 86 100 C65 B30 A47 1.3E+04 2.4E+04 580 9 180 572 232 2.0E+02 69 91 C66 B30 A47 1.3E+04 2.4E+04 600 17 180 572 362 1.1E+02 75 95 C67 B51 A64 9.3E+03 1.9E+04 580 8 180 576 206 4.6E+01 63 81 C68 B51 A64 9.3E+03 1.9E+04 600 16 180 576 336 2.3E+01 72 93 C69 B51 A64 9.3E+03 1.9E+04 620 34 180 576 466 1.1E+01 87 100 C70 B2 A5 1.7E+04 4.8E+03 580 18 20 577 40 2.8E+03 57 84 C71 B2 A5 1.7E+04 4.8E+03 600 27 3300 577 3450 4.0E+02 100 100 C72 B2 A5 1.7E+04 4.8E+03 580 18 5 577 25 3.2E+03 52 81 C73 B2 A5 1.7E+04 4.8E+03 600 27 3600 577 3750 2.0E+02 100 100 (i) C74 B2 A5 1.7E+04 4.8E+03 620 46 180 577 460 8.0E+02 100 100 X C75 B7 A11 1.2E+04 2.7E+04 580 3 180 590 115 2.2E+02 27 66 C76 B30 A47 1.3E+04 2.4E+04 620 36 180 572 492 5.1E+01 91 100 X (a) Inventive Example (i) Comparative Example (d) Surface Density of Si-based Intermetallic Compounds (number/mm.sup.2) (e) Surface Density of Al-based Intermetallic Compounds (number/mm.sup.2) (f) Equilibrium Liquid Phase Rate (%) (j) Temperature at which Liquid Phase Rate is 5% (k) Time during which Liquid Phase Rate is 5% or more (g) Surface Density of Eutectic Structures (number/mm.sup.2) (h) Rate of Triple Points of Grain boundaries where Intermetallic Compounds Exist (%) E+ in Table indicates exponential notation. For example, 1.3+04 implies 1.3 10.sup.4.

(39) As seen from Table 6, in any of Inventive Examples C61-73, the conditions specified in the present invention were all satisfied, and the bonding rate and the deformation rate were both acceptable.

(40) On the other hand, in Comparative Examples C74 and C76, because the liquid phase rate was too high, the shape could not be maintained and the deformation rate was increased. In Comparative Example C75, the liquid phase rate was too low. Furthermore, the rate of the triple points of the grain boundaries where the intermetallic compounds having the equivalent circle diameters of 1 m or more existed was also low. As a result, the bonding rare was reduced.

Third Embodiment

(41) In a third embodiment, the effect of the layer containing Zn as a main component, aiming to improve extrusion formability and corrosion resistance, was examined. First, materials having compositions (No. E1-E24, E25 and E26), listed in Table 7, were DC-cast, and billets each having 150 mm were obtained. In the alloy compositions of Table 7, - represents that the content is not more than a detection limit, and balance includes inevitable impurities.

(42) The above-mentioned billets were hot-rolled as sample materials by direct extrusion, and extruded tubes having flattened shape were fabricated as samples No. D1-D24, D43 and D44 listed in Table 8. FIG. 5 is a perspective view illustrating a part of the extruded tube having the flattened shape. The arithmetic mean waviness Wa of the sample material was about 1 m. Extrudability of the sample material in the hot extrusion was evaluated. The extrudability was evaluated to be when the sound extruded member was obtained in a length of 10 m or more by the hot rolling, when the sound extruded member was obtained in a length of more than 0 m and less than 10 m, and x when the sound extruded member was not obtained due to, e.g., the occurrence of coarse intermetallic compounds during the casting (including the case where the length of the obtained sound extruded member was 0 m).

(43) In samples No. D25-D39 listed in Table 9, the layer containing Zn as a main component was formed on the surface of the extruded tube. Samples Nos. D40-D42 listed in Table 9 represent Reference Examples in which the layer containing Zn as a main component was not formed. The Zn layer was formed by any of methods of spraying Zn, applying Zn-replaced Zn, coating Zn powder, and plating Zn.

(44) Next, a material (arithmetic mean waviness Wa of 0.3 m and plate thickness of 0.07 mm) having a composition F1 (JISA3003+1.5 Zn) in Table 7 was processed into a fin member. The fin member was formed into a corrugated shape having a height of 7 mm.

(45) The three-stage laminated test piece (mini-core), illustrated in FIG. 4, was fabricated by combining the flattened extruded tubes corresponding to each of the samples Nos. D1-D42, D43 and D44 with the above-mentioned fin members, and assembling them with the aid of the stainless jig. In the case of the mini-core thus obtained, because of the difference in coefficient of thermal expansion between the stainless jig and the aluminum material, a compression load of about 4N was generated between the stainless jig and the mini-core during the heating for the bonding. This implies that, with calculation based on a bonding area, stress of about 10 kPa is generated at the bonding interface between the fin and the tube.

(46) The mini-core fabricated as described above was dipped in a suspension solution containing 10% of non-corrosive fluoride-based flux. After drying, the mini-core was heated for 3 minutes at 580 to 600 C. in a nitrogen atmosphere, thereby bonding the fin and tube members to each other. In the sample Nos. D13, D14 and D22, the fin and tube members were bonded in vacuum without applying the flux. In the sample No. D12, fluoride-based flux containing cesium was used. In the sample No. D26, the Zn-replaced flux was applied and the heating was then performed.

(47) For the samples No. D1-D24, D43 and D44, the bonding rate between the fin and the tube was determined and evaluated in the same way as in the first embodiment. The occurrence of tube collapse was also confirmed. Furthermore, for evaluation of corrosion resistance, the CASS test was conducted for 1000 h, and the occurrence of corrosion penetrating through the tube was confirmed. The evaluation result was determined to be when the corrosion did not occur, and x when the corrosion occurred.

(48) Moreover, as in the first embodiment, the structure in a cross-section of each member was observed to determine the surface density of the eutectic structures having lengths of 3 m or more within the grains, and the rate of the triple points of the grain boundaries where the intermetallic compounds having the equivalent circle diameters of 1 m or more existed with respect to the triple points of all the grain boundaries. In addition, as in the first embodiment, the surface density of dispersed particles of the Si-based intermetallic compounds and the Al-based intermetallic compounds, having equivalent circle diameters of 0.5 m to 5 m, in the sample was measured. The measurement results are listed in Table 8.

(49) For the samples No. D25-D42, the extruded tube was peeled off from the fin, and the depth of the corrosion occurred in the extruded tube, including on its surface the layer containing Zn as a main component, was measured by the focal depth method. The measurement results are listed in Table 9.

(50) TABLE-US-00007 TABLE 7 Com- position No. Si Fe Mn Zn Sb In Mg Cu Cr Ti V Al E1 1.3 0.05 balance E2 2.0 0.05 balance E3 2.5 0.05 balance E4 3.5 0.05 balance E5 5.0 0.05 balance E6 3.5 1.00 0.3 balance E7 2.5 0.10 0.5 balance E8 2.0 0.60 1.0 0.10 balance E9 2.5 0.05 1.8 0.3 balance E10 1.5 0.25 0.1 0.1 0.3 balance E11 2.5 0.25 0.5 0.1 balance E12 2.5 0.25 0.1 0.8 balance E13 2.5 0.25 1.0 0.10 balance E14 2.0 0.10 2.0 balance E15 2.5 0.25 0.3 0.8 0.10 balance E16 0.8 0.05 balance E17 5.2 0.05 balance E18 0.8 0.60 0.3 balance E19 5.2 0.25 0.5 balance E20 2.5 2.10 1.6 balance E21 3.5 0.05 2.2 balance E22 2.5 0.25 7.0 balance E23 2.5 0.25 0.5 2.1 balance E24 2.5 0.25 0.33 0.33 0.33 balance E25 2.5 0.25 0.15 balance E26 2.5 0.25 0.15 balance F1 0.5 0.30 1.0 1.50 0.15 balance

(51) TABLE-US-00008 TABLE 8 Bonding Bonding Corrosion Extrud- Temp. Rate Tube Resistancc No. (d) ability (d) (e) ( C.) (g) (h) (%) Collapse CASS (a) D1 E1 9.4E+03 4.8E+03 600 1.1E+04 50 79.7 no D2 E2 1.2E+04 4.8E+03 600 3.3E+03 71 92.4 no D3 E3 1.4E+04 4.8E+03 600 2.2E+03 77 96.1 no D4 E4 1.8E+04 4.8E+03 600 1.3E+03 89 100.0 no D5 E5 2.2E+04 4.8E+03 580 1.1E+03 94 100.0 no D6 E6 1.7E+04 2.1E+04 600 1.4E+02 88 100.0 no D7 E7 1.4E+04 1.6E+04 600 6.5E+02 76 95.4 no D8 E8 8.1E+03 2.6E+04 600 1.5E+02 64 88.2 no D9 E9 1.2E+04 2.8E+04 600 4.3E+01 72 93.4 no D10 E10 1.0E+04 1.0E+04 600 3.3E+03 63 88.0 no D11 E11 1.4E+04 1.0E+04 600 1.1E+03 81 98.5 no D12 E12 1.4E+04 1.0E+04 600 1.1E+03 81 98.5 no D13 E13 1.4E+04 1.0E+04 600 9.6E+02 83 99.5 no D14 E14 1.2E+04 6.7E+03 600 1.4E+03 81 98.4 no D15 E15 1.4E+04 1.5E+04 600 6.4E+02 77 96.4 no D43 E25 1.4E+04 1.0E+04 600 1.4E+03 76 97.4 no D44 E26 1.4E+04 1.0E+04 600 1.4E+03 76 98.5 no (i) D16 E16 6.9E+03 4.8E+03 620 1.2E+04 47 78.4 no D17 E17 2.3E+04 4.8E+03 580 1.0E+03 95 100.0 yes D18 E18 5.9E+03 1.6E+04 620 3.4E+03 46 77.7 no D19 E19 X 2.2E+04 1.8E+04 580 2.2E+02 94 100.0 yes D20 E20 1.2E+04 3.0E+04 600 1.7E+01 77 96.3 no X D21 E21 1.6E+04 3.1E+04 600 1.1E+01 82 98.9 no X D22 E22 1.4E+04 1.0E+04 600 7.0E+02 90 100.0 no X D23 E23 1.4E+04 1.8E+04 600 2.5E+02 87 100.0 no X D24 E24 1.4E+04 1.0E+04 600 1.4E+03 76 95.5 no X (a) Inventive Example (i) Comparative Example (d) Surface Density of Si-based Intermetallic Compounds (number/mm.sup.2) (e) Surface Density of Al-based Intermetallic Compounds (number/mm.sup.2) (g) Surface Density of Eutectic Structures (number/mm.sup.2) (h) Rate of Triple Points of Grain boundaries where Intermetallic Compounds Exist (%) E+ in Table indicates exponential notation. For example, 1.3+04 implies 1.3 10.sup.4.

(52) TABLE-US-00009 TABLE 9 Layer Containing Zn as Main Component Amount Bonding Com- of Zn Temp- Corrosion Sample position Forming Deposited erature Depth No. No. Method (g/m.sup.2) Fin ( C.) (mm) (a) D25 E1 Zn spray 8 F1 600 0.04 D26 E2 (1) 8 F1 600 0.04 D27 E3 Coat Zn 8 F1 600 0.04 powder D28 E4 Zn plating 8 F1 600 0.04 D29 E5 Zn spray 1 F1 580 0.35 D30 E6 Zn spray 30 F1 600 0.26 D31 E7 Zn spray 5 F1 600 0.08 D32 E8 Zn spray 20 F1 600 0.11 D33 E9 Zn spray 15 F1 600 0.06 D34 E10 Zn spray 10 F1 600 0.05 D35 E11 Zn spray 11 F1 600 0.05 D36 E12 Zn spray 25 F1 600 0.18 D37 E13 Zn spray 0.5 F1 600 0.56 D38 E14 Zn spray 35 F1 600 0.51 D39 E15 Zn spray 8 none 600 0.12 (i) D40 E3 none F1 600 1.21 D41 E7 none F1 600 0.97 D42 E12 none F1 600 1.65 (a) Inventive Example (i) Comparative Example (1) Apply Zn-replaced flux

(53) As seen from Table 8, in any of Inventive Examples D1-D15, D43 and D44, the extrudability, the bonding rate, the tube collapse, and the corrosion resistance were all acceptable.

(54) On the other hand, in Comparative Example D16 (alloy composition E16), because the Si component did not reach the specified value, the rate of the triple points of the grain boundaries where the intermetallic compounds having the equivalent circle diameters of 1 m or more existed with respect to the triple points of all the grain boundaries was low. The bonding rate was also low.

(55) In Comparative Example D17 (alloy composition E17), because the Si component exceeded the specified value and the liquid phase rate was too high, the extruded tube was collapsed during the bonding.

(56) In Comparative Example D18 (alloy composition E18), because the Si component did not reach the specified value, the rate of the triple points of the grain boundaries where the intermetallic compounds having the equivalent circle diameters of 1 m or more existed was low. The bonding rare was also reduced.

(57) In Comparative Example D19 (alloy composition E19), because the Si component exceeded the specified value, the extruded tube was collapsed during the bonding.

(58) In Comparative Examples D20-D24, the penetrating holes were generated in the results of the CASS tests, and the corrosion resistance was inferior. Those results were attributable to the alloy compositions. More specifically, in Comparative Examples D20-D24, the Fe and Cu components (alloy composition E20), the Mn component (alloy composition E21), the Zn component (alloy composition E22), the Mg component (alloy composition E23), and the Cr, Ti and V components (alloy composition E24) exceeded the respective specified values.

(59) Regarding the effect of the layer containing Zn as a main component, as seen from Table 9, in Inventive Examples D25-D39, the sacrificial anticorrosion effect was developed with the Zn layer formed on the surface, and the corrosion depth was as small as 0.60 mm or less.

(60) On the other hand, in Reference Examples D40-D42, because Zn was not applied to the surface, the corrosion depth was as large as in excess of 0.90 mm though not penetrating. Thus, the effect obtained by forming the layer containing Zn as a main component to improve the corrosion resistance was confirmed.

INDUSTRIAL APPLICABILITY

(61) According to the present invention, since the aluminum alloy material can be bonded without using a bonding material, such as a brazing filler metal or a filler metal, a structure using the aluminum alloy material can be efficiently manufactured. Furthermore, in the present invention, change in size or shape hardly occurs between before and after bonding of bonded members. Thus, the aluminum alloy material, the structure using the aluminum alloy material, and the manufacturing method for the aluminum alloy material, according to the present invention, are remarkably effective from the industrial point of view.

LIST OF REFERENCE CHARACTERS

(62) c . . . Si composition c1 . . . Si composition c2 . . . Si composition T . . . temperature T1 . . . temperature higher than Te T2 . . . temperature higher than Ts2 Te . . . solidus temperature Ts2 . . . solidus temperature