JP2023148532A - Test method and manufacturing method for heterogeneous aluminum joint material - Google Patents

Abstract

To provide a test method and a manufacturing method for a heterogeneous aluminum joint material.SOLUTION: A test method for a heterogeneous aluminum joint material of the present invention uses plate-like test materials, wherein when the thickness of each of the test materials is defined as h, the length in a long side direction or a major axis direction as LL, and the length in a short side direction or a minor axis direction being the length LL or less, the test materials used satisfy LS, 0.13≤h/LS≤0.54. The method comprises: heating a plurality of metal test materials having the shape of the test material and not having the same component in an overlapped manner; applying a compressive force in a thickness direction to the plurality of test materials to form a heterogeneous aluminum joint material in which the plurality of test materials are joined to each other; and applying a shear force to a joint surface of the obtained heterogeneous aluminum joint material to evaluate bonding strength.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for testing and a method for manufacturing dissimilar aluminum bonding materials.

A pressure bonding method using hot plastic working is known as one of the methods for joining metals together. In particular, hot rolling has high productivity and is widely used industrially to join dissimilar aluminum plates.
When joining metals together by hot plastic working, the greater the difference in strength (difference in deformation resistance), the more difficult it is to manufacture. More specifically, in hot rolling, even if it appears to have been joined at one end, if rolling continues and a stress greater than the joint strength is applied to the joint interface, peeling may occur, impairing productivity, and in the worst case scenario. If the bonding is not successful, there is a possibility that manufacturing into the desired shape may not be possible due to misalignment.
Therefore, it is considered to be an important technical theme to understand how much joint strength can be achieved by hot plastic working.

Conventionally, for example, Patent Document 1 below discloses a technique in which when the plate thickness is 60% or more of the initial thickness, the reduction rate is specified to be 1.0% or more and 5% or less, and the reduction is performed while avoiding peeling. . Further, Patent Document 1 discloses a technique of rolling at a rolling reduction rate of 5% or more and 15% or less while the subsequent plate thickness is 30% or more and less than 60% of the initial thickness.
The following Patent Document 2 describes a pass schedule for manufacturing aluminum clad materials, in which the critical shear stress that does not cause peeling is determined based on rolling performance data, and this critical shear stress is quantified using the cumulative strain at the interface. A technique has been disclosed in which the shear stress acting on the interface is determined by numerical analysis for each rolling pass, and the shear stress is designed so that the shear stress does not exceed the critical shear stress.

In the following non-patent document 1, as shown in FIG. 10, a first cylindrical body 100 of Cu, a disc 101 of Al, and a second cylindrical body 102 of Cu are stacked and pressurized to obtain a bonding material. A test method is described in which a tensile test is performed on the first cylindrical body 100 and the second cylindrical body 102 in a direction in which they are spaced apart along their central axes, and the tensile strength is measured.
In the following non-patent document 2, as a study of the influence of the amount of interfacial slip on the bond strength in hot compression bonding, as shown in FIG. 11(A), there is a A test is described in which cylindrical test pieces 107 and 108 simulating core wood and skin wood are stacked and bonded under pressure while being heated to 500°C.
Furthermore, in Non-Patent Document 2, as shown in FIG. 11(B), a cylindrical upper test piece 110 having a lower converging inclined surface 109 between a base 105 and a punch 106 is used as an inclined compression test. A test method is described in which a cylindrical lower test piece 112 having an inclined concave surface 111 that receives the inclined surface 109 is provided. In this test method, the joint surface of the upper test piece 110 and the lower test piece 112, which are likened to the core material and the skin material, is a slope, so it is stated that the influence of the amount of interfacial slip can be ascertained.

Japanese Patent Application Publication No. 09-184038 Japanese Patent Application Publication No. 2007-098444

"Plastic Working Technology Series 19 1.4 Evaluation of Joint Condition", published by Corona Publishing, edited by Japan Society for Plastic Working, 1990, P16 Shuhei Fujii et al., “Effect of interfacial slip amount on bond strength in hot compression bonding”, 70th Plastic Working Union Lecture, P221-P222, October 12-13, 2019

The technique for adjusting the rolling reduction described in Patent Document 1 does not take into account the influence of the material composition, and therefore no technology has been found that contributes to improving the efficiency of the pass schedule, such as increasing the rolling reduction earlier to a higher rolling reduction.
The method for determining the critical shear stress described in Patent Document 2 has a problem in that it is not possible to determine the pass schedule in the case of a material configuration with little experience, and the results of application to specific materials and examples are disclosed as examples. There is a problem that has not been done.

According to the description in Non-Patent Document 1, it is stated that annealing is performed at 300°C or less after cold welding with a compression ratio of 50 to 70%, but it is not possible to control the reduction ratio to about 2 to 20%, for example. It is not easy to perform an appropriate shear test because the Al disc body 101 has a thickness of 2 mm or less.
According to the technique described in Non-Patent Document 2, in FIG. 11(A), the cylindrical lower test piece 107 is deformed into a barrel shape when subjected to pressure, and it is not easy to impart a large deformation to the interface to be joined. It is thought that there is no. Therefore, it is assumed that it is not easy to evaluate the bonding strength corresponding to a large amount of interface deformation. Moreover, it is assumed that it is not easy to increase the amount of deformation of the interface in FIG. 11(B). Moreover, it is thought that the only evaluation method is to pull the compressed test piece in FIG. 11(B) in the vertical direction as it is.

On the other hand, conventionally, samples have been collected by conducting prototype tests of hot working on a full-scale or medium-scale scale (by actually performing hot rolling), and the joint strength of each sample has been evaluated. is possible.
However, evaluation methods on actual scales and medium scales have the problem of extremely high costs for prototype testing, for example, because the conditional variables are not easy to determine. Therefore, it is desirable that the bonding strength be evaluated using a small-scale test using a compression tester, a tensile tester, or the like.

However, with conventional small-scale testing methods, it has been difficult to evaluate the bonding properties of dissimilar metals with different strengths (differences in deformation resistance).
This is because plastic working involves deformation of each material, making it difficult to evaluate bondability in welding or brazing, which do not involve large changes in shape. For example, metals with low strength may deform predominantly, metals with high strength may deform less, and in extreme cases, only metals with low strength may deform. In addition, since the shape of each metal changes due to plastic deformation, even if strength evaluations such as stretching were carried out, the shapes of the test pieces would not be uniform, making it impossible to evaluate equally as a test method.

The present invention was developed in view of the above-mentioned background, and is a test method that can perform small-scale tests using a compression tester, a tensile tester, etc. After cutting a test piece from different types of aluminum bonding materials, a shear test is conducted. The purpose of this study is to provide a technology that can evaluate bonding strength.
The present invention also provides a method for manufacturing a dissimilar aluminum bonding material using the bonding strength measurement results obtained by changing the type of material constituting the dissimilar aluminum bonding material, pressurization conditions, and heating temperature in the above-mentioned shear test. For the purpose of providing.

(1) The test method for a dissimilar aluminum bonding material according to the present invention is to use a flat plate-shaped test material, with a thickness of h, a length in the long side direction or the long axis direction of L _L , and a length equal to or less than the above-mentioned length L _L. When L _S is the length in the short side direction or short axis direction, a test material with 0.13≦h/L _S ≦0.54 is used, and the test material has the shape of the test material and the components are not the same. A dissimilar aluminum bonding material is formed by stacking a plurality of non-metal test materials to a desired temperature and applying compressive force in the thickness direction to bond the plurality of test materials. The method is characterized in that shear force is applied to the bonding surfaces of the bonding materials to evaluate the bonding strength.

(2) In the method for testing dissimilar aluminum bonding materials according to the present invention, the flat test material has a rectangular shape in plan view, and the compressive force is applied while restraining deformation in the long side direction of the test material. It is preferable that the compressive force is applied by a mold.
(3) In the method for testing a dissimilar aluminum bonding material according to the present invention, the plurality of cut surfaces are parallel to the short side or short axis direction of the test piece and extend in the thickness direction of the test piece. , the center portion of the dissimilar aluminum bonding material is cut along any one of a plurality of cut surfaces that are parallel to the long side or long axis direction of the test piece and extend in the thickness direction of the test piece. An intermediate test piece is cut out from the dissimilar aluminum bonding material so as to include the middle part of the intermediate test piece, and then cut from the intermediate test piece along two cutting planes that include the central part of the intermediate test piece and extend in the thickness direction of the intermediate test piece. It is characterized by cutting out a test piece for conducting joint strength evaluation.
(4) In the method for testing dissimilar aluminum bonding materials according to the present invention, it is preferable that the surface roughness Ra of the surfaces to be bonded before bonding of the test materials is 0.01 μm or more and 30 μm or less.
(5) In the method for testing a dissimilar aluminum bonding material according to the present invention, the rolling reduction rate when forming the dissimilar aluminum bonding material by applying the compressive force in the thickness direction of the test piece is set to 2% or more and 20% or less. It is preferable that

(6) The method for manufacturing a dissimilar aluminum bonding material according to the present invention includes changing the components of a plurality of test materials and reducing the At least one of the changes in the rate and the heating temperature was made, and the effect of the change on the bonding strength test results was determined, and the ingredients, rolling reduction rate, and The method is characterized in that dissimilar aluminum bonding materials are manufactured based on one or more conditions among heating temperatures.
(7) In the method for manufacturing a dissimilar aluminum bonding material according to the present invention, the dissimilar aluminum bonding material has a two-layer to four-layer structure in which two to four types of test materials made of pure aluminum or aluminum alloy are bonded. It is preferable that at least one of the two to four types of test materials is made of pure aluminum or an aluminum alloy having a composition different from that of the other test materials.

According to the test method according to the present invention, since the shape of the test piece is specified as 0.13≦h/L _S ≦0.54, dissimilar aluminum bonding material made of a combination of dissimilar metals with different compositions and therefore different strengths. However, by using a test material with a defined ratio range of short side length and thickness and applying shear force to this test material, the bonding strength of the interface between dissimilar metals can be reliably measured by testing.
The test method of the present invention is an evaluation method that allows small-scale tests using a compression tester, a tensile tester, etc., and is easy to implement, and can be applied to bonding materials of any combination of dissimilar metals. It has applicable advantages.
For this reason, it is possible to know in advance the bonding strength that causes interfacial delamination in dissimilar aluminum bonding materials, so when manufacturing clad materials such as two-layer or three-layer structures, it is possible to select an appropriate compression ratio according to the pass schedule. , it can be utilized in the manufacturing method of cladding material.

An example of a plate-shaped test piece suitable for use in the test method for dissimilar aluminum bonding materials according to the present invention is shown, in which (A) is a front view showing a state in which test pieces are stacked before bonding, and (B) is a front view showing a state in which the test pieces are stacked before bonding. It is a front view showing a subsequent test piece. It is a perspective view showing the same plate-shaped test piece. 1A shows a test piece of a comparative example, in which (A) is a front view showing a stacked state of plate-shaped test pieces before bonding, and (B) is a front view showing a test piece after bonding. This shows various methods for evaluating adhesive strength specified in JIS. (A) is an explanatory diagram showing a tensile test specimen specified in JIS K 6849, and (B) is an explanatory diagram showing a test piece for a tensile test specified in JIS K 6850. An explanatory diagram showing a test piece for the specified tensile shear test, (C) is an explanatory diagram showing a test piece for the compressive shear test specified in JIS K 6852, and (D) is an explanatory diagram showing a test piece for the compressive shear test specified in JIS K 6853. An explanatory diagram showing a test piece for splitting test, (E) is an explanatory diagram showing a test piece for 180° peel test specified in JIS K 6854, (F) is a T-type peel test specified in JIS K 6854. (G) is an explanatory diagram showing a test piece for the impact test specified in JIS K 6855, (H) is an explanatory diagram showing a test piece for the bending test specified in JIS K 6856. It is a diagram. FIG. 2 is an explanatory diagram showing problems when applying a plate-shaped test piece suitable for use in the present invention to a tensile shear test specified by JIS or a compressive shear test specified by JIS. This figure shows the process of cutting out a practical test piece from a dissimilar aluminum bonding material, where (A) is a perspective view showing the cutting position of the dissimilar aluminum bonding material, and (B) is a perspective view showing an intermediate test piece cut out from a dissimilar aluminum bonding material. , (C) is a perspective view showing an actual test piece cut out from the intermediate test piece. FIG. 6 is an explanatory diagram when a test is performed in which shear stress is applied to the test piece shown in FIG. (C) 6 using the test method according to the present invention. FIG. 6 is a diagram showing a case where a conventional testing machine is used to perform a test in which shear stress is applied to the test piece shown in FIG. 6(C), where (A) is an explanatory diagram of the testing machine and (B) FIG. 3 is a diagram showing the bending moment acting on the actual test piece. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing a plate-shaped test piece applied to the test method according to the present invention and a hot compression device suitable for producing the same; ) is a perspective view showing the cutting position of the dissimilar aluminum bonding material, (C) is a perspective view showing an intermediate test piece cut out from the dissimilar aluminum bonding material, and (D) is a perspective view showing a practical test piece cut out from the intermediate test piece. It is. FIG. 2 is an explanatory diagram showing a sample used in the compression method described in Non-Patent Document 1. The compression method described in Non-Patent Document 2 is shown, in which (A) is a side view showing a first example, and (B) is a side view showing a second example.

Hereinafter, one embodiment of the present invention will be described in detail based on the accompanying drawings. Note that in the drawings used in the following description, characteristic portions may be shown enlarged for convenience in order to make the characteristics easier to understand.

The present inventor prepared two aluminum alloy metal plates with different compositions, stacked these two metal plates, set them in a mold, and bonded them under pressure at 420 to 520°C to create a two-layer structure. An initial investigation test was conducted to create a dissimilar aluminum bonding material. When a bar-shaped test piece was cut out from the obtained dissimilar aluminum bonding material, a load was applied to the bonding interface of the dissimilar aluminum bonding material during cutting, and peeling occurred at the interface, making it difficult to evaluate the bonding strength. could not.
In view of the results of this initial investigation test, the present inventor has studied and deduced that the height, width, and length ratios of the dissimilar aluminum bonding materials used in the test are important.

Figure 1(A) shows a state in which two plate-shaped test pieces 1 and 2 are stacked together, which is effective in obtaining a dissimilar aluminum bonding material with a desired shape, based on the results of Examples and Comparative Examples that will be explained in detail later. FIG. 1(B) shows a model structure of a two-layer dissimilar aluminum bonding material 3 after compression bonding. In the following description of this embodiment, it is assumed that the strength of the plate-shaped test piece 1 is higher than the strength of the plate-shaped test piece 2.
By compressing the plate-shaped test pieces 1 and 2 shown in FIG. 1(A) and applying compressive force in their thickness direction, we bonded dissimilar aluminum consisting of the first layer 1A and second layer 2A shown in FIG. 1(B). Material 3 can be obtained. In this dissimilar aluminum bonding material 3, the degree of deformation of the second layer 2A produced from the plate-shaped specimen 2 with low strength is greater, and the amount of deformation of the second layer 2A is greater than that of the first layer 1A. Further, in FIG. 1(B), a portion indicated by reference numeral 4 indicates a joint portion where the first layer 1A and the second layer 2A are in close contact with each other at the interface. The joint portion 4 is formed in a region excluding both ends in the width direction of the first layer 1A and the second layer 2A.

FIG. 2 shows a perspective view of the plate-like test piece 1 before bonding. This plate-like test piece 1 has a rectangular shape in plan view, and has a long side length L _L , a short side length L _S , and a height ( thickness) h, and has the relationship h<L _S <L _L.
Further, from the comparison results between Examples and Comparative Examples described later, it is desirable that the plate-shaped test pieces 1 and 2 have a relationship of 0.13≦h/Ls≦0.54.

On the other hand, Fig. 3 shows an example of a plate-shaped test piece that tends to peel off at the interface after bonding, and as shown in Fig. 3(A), plate-shaped test pieces 5 and 6 are stacked. This is a combination of plate-shaped test pieces 5 and 6 having a structure having the relationship h>Ls. Here, it is also assumed that the strength of the plate-shaped test piece 5 is higher than that of the plate-shaped test piece 6.

As shown in FIG. 3(B), when bonded by compressive force, a two-layer structure is formed in which the first layer 5A and the second layer 6A are laminated. However, at the interface between the first layer 5A and the second layer 6A, Only narrow joints 7, 7 are generated. Since the bonded structure shown in FIG. 3(B) is only partially bonded, when the test piece is cut out, it easily peels off at the bonded interface. If there is a difference in strength between the plate-shaped specimens 5 and 6, deformation tends to concentrate on the one with lower strength (on one side of the plate-shaped specimen 6). It's predictable.

On the other hand, as shown in Figures 1 and 2, in plate-shaped specimens 1 and 2, which have a relationship of 0.13≦h/Ls≦0.54, both the upper and lower specimens deform uniformly, and the entire interface is bonded. be done. More specifically, high-strength materials tend to be smaller in deformation than low-strength materials, but by reducing h/ _LS , the deviation in the amount of deformation becomes smaller, and the deformation is approximately uniform. In this case, since the interface is wide and almost entirely joined, it is possible to process the test piece such as cutting out without any problem. It can also be said that by making the ratio of height h relatively small, pressure can be easily applied to the entire test piece, making it possible to perform a stable bonding test.

In a test piece with a rectangular cross section or a circular cross section, if h/L _S is less than 0.13, the interface is considered to be uniformly bonded, but even if L S = 20 mm, h will be small as less than 4 mm, so It becomes difficult to secure the length necessary for fixing the bonding strength test piece to a testing device, which will be described later. It is possible to increase the absolute value of h by making the test piece proportionally larger and increasing L _S , but this increases the load capacity and heating output required for the high-temperature compression testing machine, resulting in higher costs. . On the other hand, within the range of 0.13≦h/L _S ≦0.54, the above-mentioned bonding test can be carried out without difficulty. Further, in the case of a rectangular cross-sectional shape, the range of 0.2≦h/L _S ≦0.54 can be selected as a range in which a bonding test can be carried out reasonably well.
When h/L _S is less than 0.13, it is necessary to limit the reduction rate of hot compression to be evaluated. Although this embodiment does not limit proportionally changing the shape of the test piece, it is possible to balance the size of the test piece to be handled each time a test is carried out, and the capacity and scale of the testing machine that can accommodate the test piece. Therefore, if h/L _S is less than 0.13, it is considered that the cost of the testing machine becomes unnecessarily high.

Based on the idea explained above, when considering the shape of test pieces 1 and 2, h/L in the long side direction of plate-shaped test pieces 1 and 2 is smaller than that in the short side direction, so h/L in the short side direction _S is considered to be a parameter worth paying attention to.

Next, the present inventor considered that evaluation conditions are also important when conducting a test to determine bonding strength. FIG. 4 shows various adhesive strength evaluation methods specified in JIS.
Figure 4 (A) shows the test piece for the tensile test specified in JIS K 6849 and the direction of application of tensile force, and Figure 4 (B) shows the test piece for the tensile shear test specified in JIS K 6850. Indicates the direction of application of tensile force.
Figure 4(C) shows the test piece for the compression shear test specified in JIS K 6852 and the direction of force application, and Figure 4(D) shows the test piece for the splitting test specified in JIS K 6853 and the direction of force application. Indicates the direction of application.
Figure 4 (E) shows the test piece for the 180° peel test specified in JIS K 6854 and the tensile direction of the test piece, and Figure 4 (F) shows the test piece for the T-shaped peel test specified in JIS K 6854. Indicates the direction in which force is applied.
Figure 4 (G) shows the test piece for the impact test specified in JIS K 6855 and the direction of application of the impact force, and Figure 4 (H) shows the test piece for the bending test specified in JIS K 6856 and the direction in which the force was applied. Indicates the direction of application.

In view of these various evaluation conditions, the present inventor has determined that when bonding is performed by hot plastic working and the bonding strength is to be determined so that the bonded surface does not peel off during the test, it is better to We considered that shear in the along direction is more important.
Furthermore, the present inventor thought that it would be effective to perform the test piece processing described below. However, the method of processing a test piece described below is an example of the case where the present invention is implemented, and the method of processing the test piece described below is not limited to the following method when implementing the present invention.

In the case of a dissimilar aluminum bonding material 3 having a first layer 1A and a second layer 2A shown in FIG. 5(A), in order to perform a tensile shear test according to JIS K 6850 as shown in FIG. 1A and the second layer 2A need to be further processed into the shape shown in FIG. 5(B).
Furthermore, as shown in Fig. 5(C), when performing a compression shear test according to JIS K 6852, it is necessary to further process the first layer 1A and the second layer 2A, which poses the problem of easy peeling during processing. , not realistic.
If a joining method such as welding does not cause deformation before and after joining, it is possible to make a joined body assuming a strength test from the beginning, but in the case of dissimilar aluminum joining materials 3, the processing method is time-consuming. Further, it is considered that unless the work is performed with high accuracy as shown in the drawings described below, it is not possible to appropriately apply shear force to the bonding interface.

In this embodiment, processing is performed in the order shown in FIGS. 6(A), (B), and (C), an intermediate test piece 10 is cut out from the dissimilar aluminum bonding material 3, and the joint strength is evaluated by cutting out the intermediate test piece 10. The method for obtaining the test piece 11 is adopted. Using this practical test piece 11, the bonding strength can be measured by a test device 30 shown in FIG. 7, which will be described later, and the measured bonding strength can be evaluated.

The dissimilar aluminum bonding material 3 shown in FIG. 6(A) is cut out along cut surfaces S1 and S2 that exist along the thickness direction of the dissimilar aluminum bonding material 3 at respective positions indicated by chain lines L1 and L2. to prepare an intermediate test piece 10 shown in FIG. 6(B). The cut surfaces S1 and S2 are located at positions sandwiching the center part of the dissimilar aluminum bonding material 3 from both sides in the length direction of the dissimilar aluminum bonding material 3, and the respective cut surfaces S1 and S2 along the chain lines L1 and L2 are dissimilar aluminum bonding materials. It is formed at a position perpendicular to the length direction of the material 3 (a position parallel to the short side direction). As an example, when the length L _L of the dissimilar aluminum bonding material 3 is 40 mm, one cut surface S1 is drawn at a position 12 mm apart in the same length direction from one end of the dissimilar aluminum bonding material 3, and the dissimilar aluminum bonding material The other cut surface S2 is drawn at a position 12 mm apart from the other end of the bonding material 3 in the same length direction. Therefore, the length of the intermediate test piece 10 along the length direction of the dissimilar aluminum bonding material 3 is 16 mm. Incidentally, since the dissimilar aluminum bonding material 3 is actually cut out to a certain width, the length of the intermediate test piece 10 is approximately 14 to 18 mm.

Next, on the intermediate test piece 10, draw chain lines L3 and L4 spaced apart on both sides in the short side direction so as to sandwich a region with a width of 2.0 to 2.5 mm at the center part in the short side direction, and draw these chain lines L3 and L4. By cutting out the intermediate test piece 10 along the cut surfaces S3 and S4 existing in the thickness direction of the intermediate test piece 10, it is possible to obtain the rod-shaped practical test piece 11 shown in FIG. 6(C). can.
When the actual test piece 11 is cut out as described above, the joint part 4 is not formed at both ends of the first layer 1A and the second layer 2A in the width direction as shown in FIG. Assuming that there were unjoined parts at both ends in the width direction (both ends in the short side direction) of the dissimilar aluminum bonding material 3, the actual test piece 11 was cut out excluding the unjoined parts.

In the case of cutting out the dissimilar aluminum bonding material 3 and the intermediate test piece 10 shown in FIGS. 6(A) to 6(C), the cutting process shown in FIGS. 5(A) to 5(B) or the cutting process shown in FIGS. ), the load on the first layer 1A and the second layer 2A can be reduced, so the load acting on the joint surface of the first layer 1A and the second layer 2A can be reduced. Therefore, when processing the dissimilar aluminum bonding material 3 to obtain the practical test piece 11, peeling at the bonding interface can be prevented.
Regarding the cutting process, it is desirable to follow the procedure shown in Figure 6, but while taking the same consideration as above, cut out an intermediate test piece parallel to the length direction of the bonding material 3 shown in Figure 6(A), and then perform the cutting process. A procedure of cutting out the test piece 11 may also be adopted.
The actual test piece 11 is one in which a rod-shaped second joint piece 16 cut out from the second layer 2A is joined to a rod-shaped first joint piece 15 cut out from the first layer 1A. One surface of the second joint piece 15 and one surface of the second joint piece 16 are joined together in a butted state. A joint surface 17 is a combination of one surface of the first joint piece 15 and one surface of the second joint piece 16 .

Here, in the practical test piece 11, one surface of the first joint piece 15 and one surface of the second joint piece 16 are joined via the joint surface 17, and the end face 15a of the first joint piece 15 and the end face 16a of the second joint piece 16 are bonded together. are aligned flush as shown in FIG. 6(C). Hereinafter, in the rectangular surface formed by aligning the end surfaces 15a and 16a flush, the longer side will be referred to as the width W of the actual test piece 11, and the shorter side will be referred to as the thickness t of the actual test piece 11.
Once the practical test piece 11 is obtained, a shear test is performed on the practical test piece 11 using the testing apparatus shown in FIG.

FIG. 7 shows a test apparatus 30 used when implementing the test method according to this embodiment. This test device 30 has a lower clamping jig 31 and an upper clamping jig 32, and the lower clamping jig 31 and the upper clamping jig 32 are supported by a support mechanism (not shown) so that they can move toward and away from each other in the vertical direction. has been done. By attaching the test piece 11 to this test device 30 as shown in FIG. 7, a joint strength measurement test to be described later can be performed.
A support plate 33 having the same thickness as the thickness t of the test piece 11 is installed between the lower clamping jig 31 and the upper clamping jig 32 while being clamped therebetween. Further, the first bonded piece 15 of the actual test piece 11 is placed between the lower clamping jig 31 and the upper clamping jig 32 so as to be sandwiched therebetween and adjacent to the support plate 33 .
Regarding the actual test piece 11, most of the first bonded piece 15 is held between the lower holding jig 31 and the upper holding jig 32, but a part of the first bonded piece 15 on the joint surface 17 side is held by the lower holding jig 31 and the upper holding jig 32. It is held so that it slightly protrudes outward from the side surface 31a of the jig 31 and the side surface 32a of the upper holding jig 32.

In the test apparatus 30, a lower clamping jig 35 and an upper clamping jig 36 are provided outside the side surface 31a of the lower clamping jig 31 and the side surface 32a of the upper clamping jig 32, and the lower clamping jig 35 and the upper clamping jig 36 The jigs 36 are provided to be movable in the vertical direction and to be able to move toward and away from each other by a support mechanism (not shown).
Most of the second joining piece 16 protruding outward from the side surface 31a of the lower clamping jig 31 and the side surface 32a of the upper clamping jig 32 is gripped from above and below by the lower clamping jig 35 and the upper clamping jig 36. Further, a support plate 34 having a thickness equivalent to the thickness t of the actual test piece 11 is held between the lower holding jig 35 and the upper holding jig 36 together with the second bonding piece 16 .

A slight clearance (gap) is provided between the side surface 31a of the lower clamping jig 31 and the lower clamping jig 35. A lower lubricating tape 37 is attached to the side surface 31a of the lower holding jig 31, and a lower lubricating tape 38 is attached to the side surface of the lower holding jig 35 so as to fill this gap.
A slight clearance (gap) is provided between the side surface 32a of the upper clamping jig 32 and the lower clamping jig 36. An upper lubricating tape 39 is attached to the side surface 32a of the upper holding jig 32, and an upper lubricating tape 40 is attached to the side surface of the upper holding jig 36 so as to fill this gap.
In the test apparatus 30, the above-mentioned clearance can be set to, for example, about 0.8 mm. In order to fill this clearance, a lower lubricating tape 37 and a lower lubricating tape 38 are provided below the practical test piece 1, so the thickness of these lubricating tapes is approximately 0.4 mm. Further, since the upper lubricating tape 39 and the upper lubricating tape 40 are provided above the actual test piece 11, the thickness of these lubricating tapes is also about 0.4 mm.

Once the actual test piece 11 is set in the state shown in FIG. 7, the upper clamping jig 36 and the lower clamping jig 37 are lowered, and a downward pressing force is applied to the second bonded piece 16 clamped by these. to act. By applying this pressing force, a shear test can be performed on the working test piece 11.
The pressing force applied to the second joint piece 16 is gradually increased, and the pressing force at the time when the first joint piece 15 and the second joint piece 16 are separated via the joint surface 17 in the actual test piece 11 can be understood as the joint strength. . In detail, the bonding strength can be determined by dividing the maximum load when shearing force is applied by the interfacial cross-sectional area.
Note that the lower clamping jig 35 and the upper clamping jig 36 are connected to a hydraulic device (not shown) or the like, and are moved up and down. As the pressing force against the test specimen 11 increases, the bonding surface 17 will undergo shear failure at some point, so the load at the time of shear failure can be determined by a load cell provided in a hydraulic device (not shown). By dividing the load by the interfacial cross-sectional area of the test piece 11, the above-mentioned bonding strength can be determined.

In the testing apparatus 30, the shear test can be performed with the bending moment acting on the first joint piece 15 and the second joint piece 16 being minimized. Also, while closing the clearance between the lower clamping jig 31 and the lower clamping jig 35 and the clearance between the upper clamping jig 32 and the upper clamping jig 36 with lubricating tapes 37, 38, 39, and 40, the upper clamping A shear test is performed by lowering the jig 36 and the lower clamping jig 37. Therefore, the bending moment caused by the above-mentioned clearance is minimized, and the joint strength can be measured by applying only shear force to the joint surface 17 of the first joint piece 15 and the second joint piece 16, excluding the bending moment. .
In addition, by sandwiching the support plate 33 between the lower clamping jig 31 and the upper clamping jig 32, and by sandwiching the support plate 34 between the lower clamping jig 35 and the upper clamping jig 36, the actual test piece 11 is Shearing force can be applied while providing stable support.

FIG. 8(A) shows the test apparatus 30 shown in FIG. 7 in which the lower support jig 35 and the support plate 34 are omitted, a push-down jig 41 is provided instead of the upper clamping jig 36, and the push-down jig 41 is used to control the second A test device 43 is shown that presses the upper surface of the bonded piece 16 downward and performs a shear test.
In the test apparatus 43 shown in FIG. 8(A), bending moments mf ₁ and mf ₂ act on both the first joint piece 15 and the second joint piece 16, as shown in an enlarged view in FIG. 8(B).
When the bending moments mf ₁ and mf ₂ shown in FIG. 8B act, a tensile force acts on the upper side of the joint 17 between the first joint piece 15 and the second joint piece 16, and A tensile force acts in a direction to separate the two joint pieces 16. Further, a compressive force acts on the lower side of the joint portion 17 between the first joint piece 15 and the second joint piece 16, and pressure acts in a direction that brings the first joint piece 15 and the second joint piece 16 closer together. When a tensile force is applied to the upper side of the joint 17, a condition is created in which shear stress + tensile force is applied, and there is a possibility that stable results cannot be obtained as a basic test.
In this regard, the testing apparatus 30 shown in FIG. 7 makes it possible to measure the bonding strength only by shearing, with the influence of bending moment removed as much as possible, and more accurate measurement becomes possible.

FIG. 9(A) shows a hot compression apparatus 50 used to produce a dissimilar aluminum bonding material 3 suitable for use in the test for determining bonding strength of this embodiment.
The hot compression device 50 includes a square block-shaped lower mold 51 and a punch 52, and a channel groove 53 for receiving the plate-shaped test pieces 1 and 2 shown in FIG. 1 is formed on the upper surface of the lower mold 51. ing.
The groove width MW of the channel groove 53 is, for example, formed to be the same as the long side length _LL of the plate-shaped test piece 1. Further, the length of the channel groove 53 in the direction perpendicular to the groove width is larger than the long side length _LL described above. As an example, in the lower mold 51 shown in FIG. 53b reaches the other end of the lower mold 51 and is opened. The channel groove 53 is formed, for example, to a depth that is approximately several times the total thickness of the plate-shaped test pieces 1 and 2 stacked together.

The punch 52 has a convex portion 54 that can fit into the channel groove 53 of the lower die 51. The height of the convex portion 54 is equivalent to the depth of the channel groove 53. The lower die 51 and the punch 52 are provided so as to be relatively movable by a moving mechanism such as a hydraulic device (not shown). For example, the lower mold 51 is a fixed mold, and the punch 52 is supported to be movable up and down with respect to the lower mold 51. Further, a heating device (heater) not shown is built into the lower mold 51 and punch 52, and is configured to heat the lower mold 51 and punch 52 to a desired temperature (for example, 200° C. to 800° C.). has been done.
To set the plate-shaped test pieces 1 and 2 in the hot compression device 50 and join them, the plate-shaped test pieces 1 and 2 are placed in the channel groove 53 of the lower die 51 in the orientation shown in FIG. 9(A). . Since the long side length L _L of the plate-shaped test pieces 1 and 2 and the groove width of the channel groove 53 are equal, the short side ends of the plate-shaped test pieces 1 and 2 are placed at both corners of the channel groove 53 without any gaps. Insert the plate-shaped test pieces 1 and 2 into the center of the bottom of the channel groove 53.
After that, the punch 52 is lowered at a predetermined speed to insert the protrusion 54 into the channel groove 53, and the lower surface of the protrusion 54 presses the plate-shaped specimens 1 and 2, applying a compressive force in the thickness direction. By adding , it is possible to join the plate-shaped test pieces 1 and 2 and obtain a dissimilar aluminum joining material 3.

When the plate-shaped test pieces 1 and 2 are bonded by hot compression, a dissimilar aluminum bonding material 3 shown in FIG. 9(B) is obtained. The intermediate test piece 10 shown in FIG. 9(C) is obtained, and the intermediate test piece 10 is cut out along the cut planes S3 and S4 along the chain lines L3 and L4, resulting in the test piece shown in FIG. 9(D). A test piece 11 can be obtained.
The hot compression device 50 shown in FIG. A compressive force is applied to the plate-shaped test pieces 1 and 2 while suppressing their elongation. For this reason, for example, as illustrated in FIG. 1(B), the plate-shaped test piece 2 with low strength is deformed to slightly bulge on both sides in the width direction, and the amount of deformation of the plate-shaped test piece 1 is small, and the plate-shaped test piece 2 A dissimilar aluminum bonding material 3 with a large amount of deformation of the test piece 2 is obtained.

Further, a plurality of practical test pieces 11 can also be cut out from the intermediate test piece 10. In this case, in addition to the chain lines L3 and L4, chain lines L5 and L6 are drawn at equal intervals, and the cut plane extending in the thickness direction of the intermediate test piece 10 is drawn along these chain lines L5 and L6. For example, three working test pieces 11 can be obtained by cutting along the line.

“Method for manufacturing dissimilar aluminum bonding materials”
It was previously explained that a test for measuring the bonding strength can be performed on the test piece 11 cut out from the dissimilar aluminum bonding material 3 using the testing apparatus 30 shown in FIG. 7 .
In this embodiment, when producing the dissimilar aluminum bonding material 3, the material of the plate-like test pieces 1 and 2 is changed as appropriate, and the magnitude of the compressive force when applying the compressive force to the plate-like test pieces 1 and 2, By adjusting the heating temperature, it is possible to create a plurality of different types of aluminum bonding materials according to the type of material, the magnitude of the compressive force, and the heating temperature. If the above-mentioned bonding strength is measured by cutting test pieces from multiple different types of aluminum bonding materials, it is possible to understand what kind of bonding force can be obtained depending on the type of material, the magnitude of the compressive force, and the heating temperature. can do.
In other words, it is possible to understand how much interlayer bonding force can be obtained as a cladding material by applying what compression force and at what temperature, depending on the type of material.

Therefore, when manufacturing a cladding material with a two-layer laminated structure, by selecting the type of material and setting the temperature and compression force when cladding, the two-layer cladding material can be manufactured with what bonding strength. This can be determined in advance by the above-mentioned test.
Then, by selecting a material based on this grasping result and manufacturing the cladding material by rolling while applying the desired temperature and compression force, it is possible to obtain the cladding material with the desired bondability.

In the above example, the explanation was given using a two-layer structure of dissimilar aluminum bonding material 3, but the bonding strength test can be similarly performed when manufacturing a multi-layer structure cladding material such as a three-layer structure or a four-layer structure. If the cladding material is manufactured based on the test results, it is possible to manufacture a cladding material with a multilayer structure having the desired interlayer bonding properties.
In those cases, instead of the two-layered structure shown in Fig. 1(A), a three-layered structure or a four-layered structure is produced using different types of aluminum bonding materials with a three-layered structure or a four-layered structure. A practical test piece is cut out and evaluated using a test apparatus 30 shown in FIG. 7, and based on the evaluation results, a three-layer structure cladding material and a four-layer structure cladding material can be manufactured.
Even in the case of a three-layer structure or a four-layer structure, it is preferable that the above-described relationship of 0.13≦h/L _S ≦0.54 is satisfied.

In addition, in the above example, the case where the dissimilar aluminum bonding material 3 is produced using the hot compression apparatus 50 shown in FIG. 50, any device that can apply compressive force in the thickness direction of the plate-shaped test pieces 1 and 2 may be used.
Furthermore, the method and position of cutting out the practical test piece 11 from the dissimilar aluminum bonding material 3 are not limited to the cutting method explained based on FIGS. 6 and 9(A). In the example shown in FIGS. 6 and 9(A), a case has been described in which the working test piece 11 is cut out from the center of the dissimilar aluminum bonding material 3, but the working test piece 11 may be cut out from a position other than the center.

Moreover, as mentioned above, the metal material applied to the plate-shaped test pieces 1 and 2 can be exemplified by pure aluminum or an aluminum alloy, but is not limited to a combination thereof.
The plate-shaped test pieces 1 and 2 may be a combination of aluminum alloys having different compositions, or may be a combination of pure aluminum and an aluminum alloy.
Further, the dissimilar aluminum bonding material 3 is not limited to a two-layer structure, but may also have a three-layer structure or a four-layer structure. For example, it may be a laminate having a three-layer structure or a four-layer structure of aluminum alloy plates, which are often used in fields such as heat exchangers.

Aluminum alloy samples A1 to A11 described below were prepared.
・Aluminum alloy sample A1
An Al-Mn alloy A1 containing 1.5% by mass of Mn and also containing Cu and unavoidable impurities was produced. An alloy obtained by producing an ingot by melting and casting and subjecting the ingot to homogenization heat treatment at 500° C. was used in this test.
・Aluminum alloy sample A2
An Al-Mn alloy A2 containing 1.2% by mass of Mn and also containing Cu and unavoidable impurities was produced. An alloy obtained by producing an ingot by melting and casting and subjecting the ingot to homogenization heat treatment at 500° C. was used in this test.
・Aluminum alloy sample A3
An Al-Mn alloy A3 containing 1.4% by mass of Mn and also containing Cu, Mg, and unavoidable impurities was produced. An alloy obtained by producing an ingot by melting and casting and subjecting the ingot to homogenization heat treatment at 500° C. was used in this test.
・Aluminum alloy sample A4
An Al-Mn alloy A4 containing 1.2% by mass of Mn and also containing Cu, Mg, and unavoidable impurities was produced. An alloy obtained by producing an ingot by melting and casting and subjecting the ingot to homogenization heat treatment at 500° C. was used in this test.

・Aluminum alloy sample A5
An Al--Si alloy A5 containing 7.5% by mass of Si and other unavoidable impurities such as Mg and Mn was produced. An alloy obtained by producing an ingot by melting and casting and subjecting the ingot to homogenization heat treatment at 500° C. was used in this test.
・Aluminum alloy sample A6
An Al--Si alloy A6 containing 12% by mass of Si and other unavoidable impurities such as Mg and Mn was produced. An alloy obtained by producing an ingot by melting and casting and subjecting the ingot to homogenization heat treatment at 500° C. was used in this test.
・Aluminum alloy sample A7
An Al--Si alloy A7 containing 10% by mass of Si and also containing Mg, Mn, and unavoidable impurities was produced. An alloy obtained by producing an ingot by melting and casting and subjecting the ingot to homogenization heat treatment at 500° C. was used in this test.
・Aluminum alloy sample A8
An Al--Zn alloy A8 containing 2.0% by mass of Zn and other unavoidable impurities such as Mn and Si was produced. An alloy obtained by producing an ingot by melting and casting and subjecting the ingot to homogenization heat treatment at 500° C. was used in this test.

・Aluminum alloy sample A9
An Al-Zn alloy A9 containing 1.0% by mass of Zn and also containing Mn and unavoidable impurities was produced. An alloy obtained by producing an ingot by melting and casting and subjecting the ingot to homogenization heat treatment at 500° C. was used in this test.
・Aluminum alloy sample A10
An Al-Zn alloy A10 containing 2.0% by mass of Zn and also containing Si and unavoidable impurities was produced. An alloy obtained by producing an ingot by melting and casting and subjecting the ingot to homogenization heat treatment at 500° C. was used in this test.
・Aluminum alloy sample A11
An Al--Zn alloy A11 containing 5.0% by mass of Zn and other unavoidable impurities such as Mn and Si was produced. An alloy obtained by producing an ingot by melting and casting and subjecting the ingot to homogenization heat treatment at 500° C. was used in this test.

Using the alloy combinations prepared as described above, various plate-shaped test pieces were prepared using the combinations shown in Table 1 below, and a bonding test was conducted. The shape of each plate-shaped test piece is a cylindrical shape or a flat plate shape having h (height), L _L (long side length), L _S (short side length), and h/L _S shown in Table 2 below. It is.
The shape of the plate-shaped test piece of the example was rectangular or cylindrical, and the relationship of 0.13≦h/L _S ≦0.54 shown in Table 2 was established. In the example, h = compression direction (4 to 7.5 mm for a rectangle, 4 to 12 mm for a circle), L _L = long side length (40 mm for a rectangle, 28 to 32 mm for a cylinder), L _S = The short side length is within the range of 14 to 20 mm for rectangles (including copper samples, 28 to 32 mm for cylinders), but if it satisfies 0.13≦h/L _S ≦0.54, compression is possible. It is also possible to create a proportional shape depending on the specifications of the testing machine (maximum load/size that can be soaked). Further, the shape of the test piece is not limited to a rectangle or a cylinder, but may be an elliptical thin plate or a polygonal thin plate.

In the above example, the upper side (SU side) is made of high-strength material and the lower side (SL side) is made of low-strength material, but the reverse may be used. Surface smoothness is important in bonding. This sample was produced by cutting from an ingot, and the arithmetic mean roughness Ra of the surface before the bonding test was between 0.08 μm and 3.1 μm.
Further, the waviness Wa on the surface of each sample was set between 0.09 μm and 2.9 μm. It is desirable that the roughness Ra and waviness Wa match the surface roughness in the target manufacturing process, but the roughness can be set within a controllable range for the target manufacturing process, for example, by setting Ra to 0.012 μm to 25 μm. It is also possible to evaluate and consider the effect by varying the amount. Note that a confocal laser microscope was used to measure Ra and Wa. Note that for measurement, other methods may be used instead of the confocal laser microscope as long as they can measure Ra in a range of 0.012 μm to 25 μm.

A hot compression device 50 including a lower die 51 having a channel groove 53 and a punch 52 facing the lower die 51 as shown in FIG. 9(A) was used. In this example, the groove width of the channel groove 53 is set to 40 mm, which is made to match the long side length _LL in the case of a rectangle.
Similar to the previous explanation, it is also possible to make it into a proportional shape depending on the specifications of the compression tester (maximum load/size that allows temperature equalization). Further, the shape may be additionally modified to increase rigidity or devised to improve heat uniformity for high temperature tests. Note that the _LL direction does not necessarily have to be constrained. In this case, the hot compression apparatus 50 shown in FIG. 9(A) is not necessarily used, and a flat anvil (anvil, anvil) may be used for heating and compression. Since the plastic flow direction of the material changes due to restraint, the shape of the hot compression device can be selected as appropriate depending on the hot joining process to be considered.

Note that this example does not present an example in which (deformation resistance of soft material/deformation resistance of hard material) is 0.878 or more. However, the plastic deformation behavior of the two stacked sheets tends to become more homogeneous. Therefore, even if (deformation resistance of soft material/deformation resistance of hard material) is 0.878 or more, there is no possibility of departing from the technical concept of the present invention.
Even if the combination (deformation resistance of soft material ÷ deformation resistance of hard material) is less than 0.377, a test to measure the joint strength can be conducted within the scope of the technical idea of the present invention. .

An intermediate test piece with a size of 14 to 18 mm x 2 to 2.5 mm was cut out from the center of the dissimilar aluminum bonding material obtained using a hot compression device, with the thickness direction unchanged (Figure 6 (A) )
More specifically, the length in the short side (L _S ) direction _is 40 mm in the case of a rectangle, and 20 to 40 mm in the case of a cylinder. Cutting was carried out so that the length was 14 to 20 mm for the case and 28 to 32 mm for the cylinder.
Although the method of the present invention can uniformly bond the entire interface, there may be cases where the bond is not perfect (parts of both ends of the interface in the width direction are not connected), as shown in the image of the bonded part shown in Figure 2 (B). Therefore, it is preferable to cut out the sample from the center as much as possible.

If the efficiency of the test is more important than the accuracy of the test, a shearing force may be directly applied to the dissimilar aluminum bonding material 3 without cutting out the test piece. In this example, a shearing force was applied to the cut-out working test piece 11 using a testing apparatus 30 shown in FIG. 7 to measure the bonding strength.
Note that, depending on the absolute values of L _L and L _S , the shape of the cut-out test piece may be made into a proportional shape within the same ratio range. Before applying shearing force, it is preferable to smooth the surface by polishing with No. 1000 or higher. Thereafter, the dimensions of the actual test piece were measured, and the interfacial cross-sectional area of the actual test piece was determined.

The deformation resistance shown in Table 1 was evaluated by a cylindrical compression test with a diameter of 8 mm and a height of 12 mm. These are the results at 480°C, strain rate of 0.1/sec, and logarithmic strain of 0.1. As shown in Tables 2 to 4 below, COM1 to COM7 were conducted at 440°C to 520°C.
The (compression) speeds shown in Tables 2 to 4 indicate the compression speed of the punch during hot compression.
The rolling reduction ratios shown in Tables 2 to 4 are calculated based on the total thickness of the two sheets before and after compression (the total thickness of the two plate-shaped specimens and the total thickness of the first and second layers after compression). did.
The joint surface pressures shown in Tables 2 to 4 were determined by dividing the maximum load during hot compression by the initial sample cross-sectional area.
The bonding strengths shown in Tables 2 to 4 were determined by dividing the maximum load when shearing was applied by the interfacial cross-sectional area.

Nos. 1 to 7 and 19 to 28 shown in Tables 2 and 3 are comparative examples. Since the shape of the test piece was h/L _S >0.54, the test piece could not be processed after hot compression, and the bonding strength could not be evaluated. In Comparative Examples Nos. 1 to 7 and 19 to 23, wire cutting, which does not place much stress on the interface of the specimen, was selected to process the specimen, but there were some problems such as peeling of the bonded surface during handling during processing. A problem occurred and the test piece processing could not be completed to the end.
No. 8 to 18 shown in Table 2 and No. 29 to 63 shown in Table 2 and Table 3 are Examples. The shape of the test piece was in a range that matched the formula 0.13≦h/L _S ≦0.54, and a test piece in a stable bonded state was obtained, making it possible to evaluate the bonding strength. Note that for Nos. 8 to 18 and 24 to 63, grindstone cutting was used from the viewpoint of work efficiency, but test pieces could be processed without problems if 0.13≦h/L _S ≦0.54. When processing test pieces No. 8 to 18 and No. 24 to 63, wire cutting may be performed.

Test pieces No. 1 to 8, No. 19 to 23, No. 28, No. 35, and No. 45 to 47 have a cylindrical shape. h/L _S was calculated by setting h = cylinder height (4 to 30 mm) and L _S = cylinder diameter (20 to 32 mm).
Test pieces no. 9 to 18, no. 24 to 27, no. 29 to 34, no. 36 to 44, and no. 48 to 63 are rectangular in plan view. h/L _S was calculated by setting h = compression direction (4 to 9 mm), L _L = long side length (40 mm), and L _S = short side length (14 to 20 mm).
Among the samples having a rectangular shape in a plan view, compression was performed in the long side direction for Nos. 24, 26, 29, 31, 33, 36, and 42 without restraint, and for the other Nos. The sample was compressed in a state where the long side direction was constrained by the channel groove 53 of the hot compression device 50 shown in FIG. 9(A).
Nos. 11 to 15 are example samples in which the test was repeated five times under the same conditions. Practical stability was obtained as a joint strength measurement test. It is preferable to conduct repeated tests with n=3 to 5 and take the average.

From the results shown in Tables 2 to 4, it was found that temperature, compression speed, rolling reduction, and lubrication can be easily varied, and that the relationship between hot working conditions and joint strength can be investigated by systematically acquiring data. .
Note that the lubrication shown in Tables 2 to 4 refers to the treatment between the lower die and punch and the sample surface, and lubrication was performed without lubrication and with BN powder applied by spraying. By applying lubrication, the joint surface pressure can be lowered and the influence of the joint surface pressure can be discussed. Note that the lubrication means is not limited to lubrication using BN powder, and other lubrication means may be applied.

As shown in Table 1, various combinations of materials were used as listed in COM1, COM2, COM3, COM4, COM5, COM6, and COM7. As shown in the results in Tables 2 to 4, the test could be carried out without any problem with any material type, and the bonding test to determine the bonding strength between dissimilar aluminum alloys could be carried out.

"Manufacture of 3-layer cladding material"
A three-layer cladding material was fabricated in which skin material was adhered to both sides of the core material.
A three-layer cladding material was manufactured in which one skin material was formed from the aforementioned A11 alloy, the core material was formed from A4 alloy, and the other skin material was formed from A5 alloy. The cladding ratio of one skin material was 15% with respect to the core material, and the cladding ratio of the other skin material was 20% with respect to the core material. The total thickness of the three-layer clad material was 600 mm. The rolling temperature was set at 480°C.
When manufacturing such a three-layer cladding material, Example no. shown in Tables 2 to 4 is used. 8 to 18 and no. As can be seen from the results in Tables 29 to 60, the bonding strength of grade COM6 (A4-A11) and grade COM7 (A4-A5) is low, and bonding by hot rolling is not easy. It can be easily determined by looking at the test results in step 4.

For COM6 (A4-A11), the rate of increase in bonding strength due to an increase in rolling reduction (comparison of no. 55 to 57) is small, and the bonding strength only reaches 10 MPa or more when the rolling reduction is 10% or more.
COM7 (A4-A5) (from a comparison of nos. 58 to 60) has a low joint strength when the rolling reduction is small, but the increase rate of joint strength with an increase in rolling reduction is large, and the joint strength increases at a rolling reduction of about 8%. The value exceeds 10 MPa. Therefore, it can be seen that at a rolling reduction rate of 10% or more, the bonding strength of any combination becomes 10 MPa or more.

Based on the bonding test results shown in Tables 2 to 4, three-layer cladding materials were manufactured under the following conditions.
While the plate thickness was over 90% of the initial thickness, rolling was performed at a rolling reduction rate of 5% or less in each pass. This is because by setting the rolling reduction rate per pass to 5% or less, the bonding strength can be gradually increased without causing peeling.
While the plate thickness was 50% or more and 90% or less of the initial thickness, rolling was performed at a rolling reduction rate of 5.1% or more and 15% or less per pass. As mentioned above, in the joint strength evaluation of this test, for both COM5 (A4-A11) and COM6 (A4-A5), the joint strength was 10 MPa or more when the reduction rate was 10% or more (plate thickness was 90% or less of the initial value). This is because peeling does not occur even if the per-pass rolling reduction rate is increased to 5.1% or more. Here, if the per-pass rolling reduction rate exceeds 15%, it is assumed that peeling will occur due to shear stress generated at the interface.

If the subsequent plate thickness is less than 50% of the initial thickness, problems as a cladding such as bonding cannot occur, so rolling was carried out according to the production convenience of rolling without specifying conditions.
As a result of the above, it was possible to roll the material well without any noticeable displacement of the interface during rolling, and to obtain the desired three-layer cladding material.
Therefore, based on the results shown in Table 2, it was possible to successfully manufacture a three-layer cladding material with good interlayer bonding properties without having to carry out multiple expensive trial productions with a material configuration that is difficult to bond.
It is also possible to select a more efficient pass schedule by desirably determining the shear stress generated by numerical analysis or the like and comparing it with the bonding stress at that moment.

DESCRIPTION OF SYMBOLS 1, 2...Plate test piece, 1A...First layer, 2A...Second layer, 3...Different aluminum joining material, 4...Joint part, 10...Intermediate test piece, 11...Execution test piece, 15...First joining Piece, 16...Second joint piece, 17...Joint portion, 30...Testing device, 31...Lower clamping jig, 32...Upper clamping jig, 33...Support plate, 34...Support plate, 35...Lower clamping jig , 36... Upper clamping jig, 37, 38, 39, 40... Lubricating tape, 50... Hot compression device, 51... Lower mold, 52... Punch, 53... Channel groove, 54... Convex portion.

Claims (7)

It is a flat test material, the thickness is h, the length in the long side direction or major axis direction is L _L , and the length in the short side direction or short axis direction that is equal to or less than the above length L _L is L _S Sometimes, a test material with 0.13≦h/L _S ≦0.54 is used, and a plurality of metal test materials having the shape of the test material and having different components are stacked and heated to a desired temperature. A dissimilar aluminum bonding material is formed by bonding the plurality of test materials by heating and applying compressive force in the thickness direction, and a shearing force is applied to the joint surface of the obtained dissimilar aluminum bonding material to measure the bonding strength. Test method for dissimilar aluminum bonding materials to evaluate The flat test material has a rectangular shape in plan view, and the compressive force is applied by a mold that applies the compressive force while restraining deformation of the test material in the long side direction. Test method for dissimilar aluminum joints. A plurality of cut surfaces parallel to the short side or short axis direction of the test piece and extending in the thickness direction of the test piece, or parallel to the long side or long axis direction of the test piece, and , cutting an intermediate test piece from the dissimilar aluminum bonding material so as to include the center portion of the dissimilar aluminum bonding material along any one of a plurality of cut surfaces extending in the thickness direction of the test piece; A claim characterized in that test pieces for joint strength evaluation are cut out from the intermediate test piece along a plurality of cutting planes that include a central portion of the intermediate test piece and extend in the thickness direction of the intermediate test piece. The method for testing dissimilar aluminum bonding materials according to claim 1 or claim 2. The method for testing dissimilar aluminum bonding materials according to any one of claims 1 to 3, wherein the surface roughness Ra of the surfaces to be bonded before bonding in the test material is 0.01 μm or more and 30 μm or less. According to any one of claims 1 to 4, the rolling reduction ratio when forming the dissimilar aluminum bonding material by applying the compressive force in the thickness direction of the test piece is 2% or more and 20% or less. Test method for dissimilar aluminum bonding materials described. In the method for testing dissimilar aluminum bonding materials according to any one of claims 1 to 5, at least one of changing the components of the plurality of test materials, changing the rolling reduction rate, and changing the heating temperature. Implement one type of change, determine the effect of the change on the joint strength test results, and change one or more conditions among the ingredients, rolling reduction rate, and heating temperature that gave good joint strength. A method for producing a dissimilar aluminum bonding material based on the method of producing a dissimilar aluminum bonding material. The dissimilar aluminum bonding material is a dissimilar aluminum bonding material having a two-layer structure to a four-layer structure in which two to four types of test materials made of pure aluminum or aluminum alloy are bonded, and the two to four types of test materials are bonded together. 7. The method for producing a dissimilar aluminum bonding material according to claim 6, wherein at least one of the four types of test materials is made of pure aluminum or an aluminum alloy having a composition different from that of the other test materials.

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