JP6821419B2 - Composite members, aluminum alloy members for joining and their manufacturing methods - Google Patents

Description

The present invention relates to a composite member formed by joining a member to be joined to an aluminum alloy casting, an aluminum alloy member for joining made of the casting, and a method for manufacturing the same.

A composite member in which a plurality of members having different shapes, materials, functions, etc. are joined is used in order to cope with the complexity, size, multifunction, weight reduction, and the like of the members. Joining is performed by bonding, welding, fastening, joining, etc. according to the required specifications of the composite member, etc., but mechanical joining is often used because strong joining can be performed relatively easily. For example, members that need to be attached / detached are fastened with screws (bolts, nuts, etc.), and members that do not need to be attached / detached are joined with rivets.

By using rivets, it is possible to easily join different materials that cannot be welded. Recently, attention has been paid to joining using a self piercing rivet (Self Piercing Rivet / simply referred to as "SPR"), which does not require drilling work (that is, self-drilling type) and enables strong bonding. For example, there is a description in the following patent document regarding a case where SPR is struck on a die-cast member made of an Al—Si alloy to join another thin plate ([0029], FIG. 3, etc.).

Japanese Unexamined Patent Publication No. 2010-90459

Patent Document 1 states that a die-casting member made of an Al—Si alloy having an adjusted component composition is heat-treated (solution treatment, aging treatment) to improve ductility, thereby suppressing cracking that occurs when the SPR is struck. is suggesting.

However, in Patent Document 1, although the portion other than the joint portion satisfies sufficient characteristics without heat treatment, the heat treatment is performed only to prevent cracking due to local deformation when the SPR is struck. There is. Moreover, in order to prevent blister (expansion of high pressure gas nest) that occurs during heat treatment of the die casting member, a special high vacuum die casting is also performed. Such a method leads to high cost of the die casting member and is not preferable.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an aluminum alloy member for joining having a joint portion having excellent crack resistance and a method for manufacturing the same by a method different from the conventional method. To do. Another object of the present invention is to provide a composite member in which the aluminum alloy member for joining and the member to be joined are riveted.

As a result of diligent research to solve this problem, the present inventor has conceived to improve the crack resistance of the joint by crystallizing a large amount of highly ductile primary aluminum in the joint where cracks are likely to occur due to local deformation. , I actually confirmed the effect. By developing this result, the present invention described below has been completed.

<< Aluminum alloy member for joining >>
(1) The aluminum alloy member for joining of the present invention is an aluminum alloy member for joining, which is made of a cast aluminum alloy and includes a joining portion that is plastically deformed and mechanically joined, and a non-joining portion that is not involved in joining. The aluminum alloy contains 6 to 12% of Si with 100% by mass (simply referred to as "%") as a whole, and the junction has a primary crystal ratio, which is the abundance ratio of primary aluminum, which is the non-junction. Larger than the department.

(2) According to the aluminum alloy member for joining (also simply referred to as "Al alloy member") of the present invention, it is not necessary to perform heat treatment or the like, and while suppressing cracks or the like, the mechanical quality is stable by SPR or the like. Can be joined. The reason for this can be considered as follows.

Castings containing a relatively large amount of Si do not always have sufficient ductility. However, the joint portion according to the present invention has more primary aluminum (appropriately referred to as "α-Al") than the portion other than the joint portion (non-joint portion), and has high ductility. Therefore, the joint portion according to the present invention is hard to crack and exhibits excellent crack resistance even if SPR is studded at the time of joining and a large deformation occurs locally.

Since the non-joint portion, which occupies most of the Al alloy member of the present invention, has a normal metal structure (casting structure) according to the overall alloy composition and cooling rate (solidification rate), the original planned structure is formed. Demonstrate mechanical properties, etc. Therefore, even if the joints having a relatively large amount of α-Al are scattered, the mechanical properties (strength, etc.) of the Al alloy member of the present invention are not significantly deteriorated.

<< Manufacturing method of aluminum alloy member for joining >>
The present invention can also be grasped as a method for manufacturing an aluminum alloy member for joining. That is, the present invention is a method for manufacturing an aluminum alloy member for joining, which is composed of an aluminum alloy casting and includes a joint portion that is mechanically joined by plastic deformation and a non-joint portion that is not involved in the joining. It is provided with a pouring step of pouring a molten aluminum alloy containing 6 to 12% of Si as 100% into a mold, and a cooling step of cooling and solidifying the molten metal poured into the mold, and further, the cooling. A method for manufacturing an aluminum alloy member for joining, which comprises a local pressurizing step of locally pressurizing the molten metal in which primary crystal aluminum is crystallized and is in a solid-liquid coexisting state in a region corresponding to the joining portion during the process. It may be.

<< Composite member >>
Further, the present invention can be grasped as a composite member in which the above-mentioned Al alloy member and another member are joined. That is, in the present invention, the above-mentioned aluminum alloy member for joining, at least one member to be joined to be joined to the aluminum alloy member for joining, and the tip portion penetrating the side of the aluminum alloy member for joining are the aluminum alloy member for joining. It may be a composite member including an aluminum alloy member for joining and a joining tool for joining the member to be joined by plastically deforming in the joining portion of the above.

《Others》
(1) The primary crystal ratio according to the present invention is calculated from the area ratio of α-Al obtained by image processing a metallographic photograph (observation area: 20 × 5 mm) obtained by observing the relevant portion with an optical microscope. .. For the primary crystal ratio of the joint, basically, the metallographic structure in the central region of the joint is observed. However, for the joint where plastic deformation occurs after joining, observe the metal structure in the region where plastic deformation does not occur or the region where the amount of plastic deformation is the smallest. For the non-joint portion, the primary crystal ratio may be calculated by observing the metallographic structure of a region not affected by the joint portion (for example, a region separated by at least 10 mm from the end of the joint portion).

The size and shape of the joint portion are appropriately adjusted depending on the joining method or the form of the joining tool. For example, when SPR is used, it is preferable to set the joint portion one size larger than the plastic deformation region of the leg portion (shaft portion). Normally, the plastic deformation area of the leg of the SPR and the occupied area of the head are about the same size, so that the area of the joint is, for example, 1 to 2 times the area of the head of the SPR, or even 1. It may be 2 to 1.6 times. If the head of the SPR is circular, the joint may have, for example, a circular shape having a diameter of 1 to 1.5 times or even 1.1 to 1.3 times the diameter of the head of the SPR.

The non-joining portion is a region not involved in joining, but in other words, it can be said to be a region other than the joining portion or a region that is not plastically deformed at the time of joining. When it is necessary to clarify the boundary between the bonded portion and the non-joined portion, the determination may be made based on the primary crystal ratio. For example, the boundary between the two may be around 1.1 times the primary crystal ratio of the non-joint portion sufficiently separated from the junction.

(2) Unless otherwise specified, "x to y" in the present specification includes a lower limit value x and an upper limit value y. A range such as "ab" may be newly established with any numerical value included in the various numerical values or numerical ranges described in the present specification as a new lower limit value or upper limit value.

It is explanatory drawing which shows the state of the local pressurization process schematically. It is an overview view of the mold (main part) used for casting and the manufactured casting. It is a schematic diagram which shows the SPR bonding member which concerns on a comparative sample. It is an X-ray CT photograph which shows the cross section of the SPR joint part which concerns on each sample. It is a metallographic photograph of the joint portion related to each sample. It is a bar graph which shows the mechanical property which concerns on each sample. It is a photograph which shows each metal structure at the time of changing the pressurization start (solid phase ratio). It is a solidification curve of the molten Al alloy used for producing a sample. It is a correlation diagram between the solid phase ratio at the start of pressurization and the number of cracks generated at the time of SPR joining. It is a correlation diagram between the amount of Si contained in a casting and its mechanical properties. It is a dispersion figure which shows the relationship between the material (cooling rate) of a mold, and the bending or bending strength of a casting. It is a dispersion figure which shows the relationship between the material (cooling rate) of a mold, and the amount of Si or Mg which is solid solution in primary crystal Al.

One or more components arbitrarily selected from the present specification may be added to the components of the present invention described above. The contents described in the present specification appropriately apply not only to the Al alloy member of the present invention, but also to the manufacturing method thereof and the composite member using the Al alloy member. Moreover, even a methodical component can be a component related to an object in a certain case. Whether or not which embodiment is the best depends on the target, required performance, and the like.

《Joint part》
The bonded portion according to the present invention has a higher primary crystal ratio than the non-joined portion. For example, the ratio of the primary crystal ratio of the bonded portion to the primary crystal ratio of the non-joined portion (primary crystal ratio) is 1.2 or more. It is preferably 25 or more, more preferably 1.3 or more. From the viewpoint of balancing the characteristics of the bonded portion and the non-joined portion, it is preferable that the upper limit of the primary crystal ratio is 2 or less, more preferably 1.5 or less.

The joint has a higher primary crystallinity than the surroundings (non-join) and has relatively high ductility, but as the alloying elements (Si, etc.) contained in α-Al increase, the ductility of the joint decreases. obtain. Therefore, it is preferable that the solid solution amount of the alloying element contained in the primary crystal aluminum is smaller in the joint portion than in the non-junction portion.

Since the solid solution amount of an alloy element differs depending on the alloy composition (type of element, its content), cooling rate, etc., it is difficult to unconditionally specify it. Therefore, for example, it is preferable that the total amount of alloying elements dissolved in α-Al is 0.05% or more, 0.1% or more, and further 0.15% or more less in the bonded portion than in the non-bonded portion. ..

Further, in the Al alloy member (casting) of the present invention, the joint portion having a high primary crystal ratio exhibits high crack resistance even without heat treatment. In such unheated castings, the non-joint remains in the cast structure and often has a eutectic network structure. Conversely, when heat-treated, the eutectic network structure collapses, resulting in a structure in which granular α-Al and eutectic crystals are dispersed. The eutectic network structure is a structure in which eutectic (Al—Si system) are connected so as to surround α—Al.

Incidentally, the joint portion according to the present invention has, for example, a circular shape or a square shape having a diameter or one side of about 3 to 15 mm and further about 4 to 10 mm, although it depends on the joining method (joining tool). Since the joint portion itself is not large, even if a plurality of joint portions are arranged in the Al alloy member, the characteristics (strength, etc.) of the Al alloy member are hardly affected.

《Al alloy》
The Al alloy member of the present invention is made of an Al—Si based alloy for casting, and preferably contains at least 6 to 12%, 7 to 11%, and further 8 to 10.5% of Si. If the amount of Si is too small, the castability is lowered, the shrinkage amount is increased, and casting defects are likely to occur inside the casting. When the amount of Si is excessive, the mechanical properties (particularly elongation) of the casting are likely to be deteriorated, and the crack resistance at the joint may also be lowered. Unless otherwise specified, the alloy composition referred to in the present specification is a mass ratio shown as 100% by mass (simply referred to as "%") including both the bonded portion and the non-joined portion.

The Al alloy according to the present invention may contain alloying elements such as Mg, Ti, Zr, Cu and Fe or modifying elements such as Sr, Na and Sb in addition to Si. Specifically, it is as follows.

Mg strengthens the Al matrix and is preferably contained in an amount of 0.1 to 1%, more preferably 0.2 to 0.7%. If the amount of Mg is too small, the effect cannot be sufficiently obtained, and if the amount of Mg is too large, Mg ₂ Si and the like may crystallize to reduce ductility and toughness.

Ti and Zr refine the crystal grains and strengthen the Al matrix, 0.05 to 0.3% and 0.07 to 0.2%, respectively, for a total of 0.06 to 0.4% and further. It is preferably contained in an amount of 0.08 to 0.3%. If Ti and / or Zr is too low, the effect is poor, and if they are too high, coarse Ti or Zr compounds will crystallize in the cast structure, which in turn reduces the mechanical properties (especially ductility) of the casting. Can be done.

Sr, Na or Sb can refine eutectic Si to improve the mechanical properties (particularly ductility or toughness) of castings (mainly non-joints). A small amount of these modifying elements is sufficient, and for example, the total content may be 0.003 to 0.05% and further 0.01 to 0.03%.

<< Manufacturing method of aluminum alloy member for joining >>
The Al alloy member made of a casting is obtained through a pouring step of pouring the above-mentioned molten Al alloy into a mold and a cooling step of cooling the molten metal in the mold to solidify it. Then, the joint portion according to the present invention is subjected to a local pressurization step of locally pressurizing the molten metal in which α-Al crystallizes and is in a solid-liquid coexisting state in the region corresponding to the joint portion during the cooling step. It is formed. FIG. 1 schematically shows how a joint having a high primary crystallinity is formed by this local pressurization step. In order to accurately perform such local pressurization, the manufacturing method of the present invention is preferably performed by die casting in which molten metal is poured into the cavity of the mold while being pressurized.

At least a part of the local pressurization is preferably performed when the solid phase ratio of the molten metal is 0.25 to 0.95, 0.3 to 0.8, and even 0.4 to 0.7. If local pressurization is applied when the solid phase ratio is too small, there are few primary crystals and the primary crystal ratio at the junction does not increase. If local pressurization is performed when the solid phase ratio is excessive, a high primary crystal ratio cannot be expected because the fluidity of the molten metal is low. Although details will be described later, the solid phase ratio according to the present invention is determined based on the solidification curve and the measured cooling curve.

The cooling step according to the present invention is preferably performed at a cooling rate of 750 ° C./s or less, more preferably 700 ° C./s or less. If the cooling rate is excessive, a large amount of alloying elements such as Si may be dissolved in α—Al, and the ductility of the joint may decrease.

The maximum cooling rate through the cooling process may be within the above range. Normally, the cooling rate is maximized immediately after pouring the molten metal, and the solid solution amount of the alloying element is almost fixed at the initial stage when α-Al crystallizes. Therefore, the cooling rate according to the present invention may be considered as the cooling rate after the completion of the pouring process or the start of the cooling process. The cooling rate is preferably determined by the time change of the temperature measured at or near the joint.

<< Composite member >>
The Al alloy member of the present invention can be joined to another member to be joined having a different shape, material and the like. Although there are various joining methods, it is preferable to join by rivets (particularly SPR) by utilizing the high ductility or high crack resistance of the joined portion.

The member to be joined may be a metal member such as an Fe-based member (particularly a steel plate), an Al-based member, an Mg-based member, or a Ti-based member, a resin member, or a composite member such as various FRPs. The "X-based member" means a pure X member, an X alloy member, or a composite member containing X. Further, at least the rivet joint portion of the member to be joined preferably has a (thin) plate shape through which the rivet penetrates.

Various samples (Al alloy members) were produced, their mechanical properties and crack resistance were evaluated, and the metallographic structure was observed. The present invention will be described in more detail with reference to such specific examples.

[Example 1]
<< Production of sample >>
(1) Using a mold (mold) equipped with a pressure pin as shown in FIG. 2, a casting (Al alloy member) made of an Al alloy as shown in the figure was die-cast (casting step). Specifically, the molten Al alloy prepared to the desired composition from the bottom is pressurized with a plunger (not shown) at the bottom of the figure, and injected into a rectangular cavity (70 mm x 50 mm x 5 mm) through a runner and a gate. (Pouring process). At this time, the moving speed of the plunger was set to 0.4 m / s, and the casting pressure was set to 65 MPa. Unless otherwise specified, tool steel (JIS SKD61) was used for the mold.

It is installed in the center of the cavity (the area corresponding to the joint) at a predetermined time (at the start of pressurization / 0.1 to 2.1 seconds after the start of injection) after the completion of pouring (injection) of the molten metal. The pressure pin (φ17 mm) that had been used was activated. Specifically, the pressure pin, which had been retracted 7.2 mm outward from the inner wall surface of the cavity in advance, was pressed at 271 MPa. As a result, a part of the molten metal in which primary crystals (α-Al) were crystallized in the cavity and was in a solid-liquid coexisting state was locally pressurized.

In this way, a plate-shaped casting (sample) having the following three types of Al alloy compositions having different amounts of Si was obtained. Each alloy composition is a mass ratio with the entire Al alloy (molten metal) as 100% by mass. In addition, except for Example 3 described later, the following measurements, observations and evaluations were carried out on the casting made of the alloy 1.
Alloy 1: Al-7% Si-0.3% Mg-0.1% Ti
Alloy 2: Al-8.5% Si-0.3% Mg-0.1% Ti
Alloy 3: Al-10% Si-0.3% Mg-0.1% Ti
(2) As a comparative sample, a casting not subjected to the above-mentioned local pressurization was also produced.

(3) For SPR joining, a test piece having a wall thickness of 5 mm was prepared by flat-cutting each of the above-mentioned castings. As the SPR, a boron steel head (disk-shaped portion); φ8 mm, legs (cylindrical portion): φ5.3 mm × length 6 mm × wall thickness 1 mm were used. As the member to be joined, a steel plate having a size of 70 mm × 50 mm × 1 mm was used.

For joining, the members to be joined are placed on top of the test piece (joint) corresponding to the area where the pressure pins are placed, and SPR is applied from the member to be joined using the POP JOISPND hydraulic system with a load of 56 kN and a speed. It was studded at 100 mm / s.

《Observation》
(1) First, FIG. 3 shows a state in which SPR bonding was performed using a comparative sample (sample C1 / alloy 1). As is clear from FIG. 3, when SPR bonding was performed in a region where local pressurization was not performed, cracks occurred at locations where local deformation was large.

Next, with respect to the sample C1 and the locally pressurized sample (sample 11 / alloy 1 / at the start of pressurization: 0.6 s / solid phase ratio: 0.5), the SPR junction is formed into two cross sections. An X-ray CT photograph taken at the position is shown in FIG. As is clear from FIG. 4, it was confirmed that, unlike the sample C1, the sample 11 subjected to the local pressurization did not crack even in the portion where the local deformation was large.

(2) FIG. 5 shows a photograph of the metallographic structure of the region corresponding to the joint between the sample 11 and the sample C1 observed with an optical microscope. Each tissue photograph was processed by a Luzex image analyzer, and each primary crystal ratio was determined from the ratio of primary crystal (white part) and eutectic (gray part). It was found that the primary crystal ratio of Sample 11 increased 1.3 times (95% / 73%) with respect to the primary crystal ratio of Sample C1.

《Measurement》
The mechanical properties of Sample 11 and Sample C1 are shown in FIG. As is clear from FIG. 6, although the tensile strengths of both samples are substantially the same, the (breaking) elongation of sample 11 is about 1.8 times (13.7% / 7.) that of sample C1. It increased rapidly to 7%) and was found to be extremely ductile. The tensile test was carried out using a tensile test piece cut out so that the region corresponding to the joint was in the center.

From the above, it was confirmed that by performing local pressurization at a predetermined timing after the completion of pouring into the cavity, a casting having a highly ductile joint that does not crack even if SPR joint is performed can be obtained.

[Example 2]
(1) Using the molten metal made of the alloy 1, various samples 21 to 24 in which the start of pressurization for local pressurization was changed were produced. The solid phase ratio and the metallographic structure (macrostructure and microstructure) of each sample at the start of pressurization are summarized in FIG. 7. The macrostructure is a cross-section observed as it is, but the microstructure is 200 times larger than that observed with an optical microscope.

The solid phase ratio shown in FIG. 7 is the solid phase ratio of the molten metal at the start of pressurization determined from the solidification curve shown in FIG. The cooling curve shown in FIG. 8 was obtained by actually measuring the elapsed time from the start of injection of the molten metal into the cavity and the temperature of the molten metal in the cavity. The solid phase ratio shown in FIG. 8 is calculated from the amount of latent heat released by performing solidification analysis based on the measured cooling curve.

Incidentally, when the pressure pin pressure is pressed at 271 MPa, the pressure pin is in a full stroke state in about 0.05 seconds, and its inner end surface is flush with the inner wall surface of the cavity.

When local pressurization is performed when the solid phase ratio is almost 0 as in sample 21 shown in FIG. 7, the pressurized portion becomes a metal structure in which a eutectic network exists between primary crystal Al dendrites and is locally added. The metal structure was the same as when no pressure was applied.

On the other hand, as in Samples 22 and 23, when local pressurization was performed when the solid phase ratio increased, a metallographic structure in which almost the entire surface was occupied by the primary crystal Al phase was obtained. As in sample 24, even if local pressurization was performed when the solid phase ratio was considerably high, eutectic (Al—Si) appeared, but the metal structure was mostly occupied by primary crystal Al.

(2) Using the test pieces made of the castings shown in Samples 21 to 24, SPR joining was performed in the same manner as in Example 1. At that time, the number of cracks generated in each test piece was visually counted. The correlation between the number of cracks obtained in this way and the solid phase ratio of each sample shown in FIG. 7 is shown in FIG.

As is clear from FIG. 9, it was found that even if local pressurization was performed when the solid phase ratio was 0.2 or less, a metal structure having a high primary crystal ratio could not be obtained, and cracking during SPR bonding could not be suppressed so much. It was. On the other hand, if local pressurization is performed when the solid phase ratio is 0.3 or more and even 0.4 or more, a metal structure having a high primary crystal ratio is obtained, and cracks hardly occur even if SPR bonding is performed. I understand.

[Example 3]
Similar to the casting using alloy 1 (sample 11, sample C1) shown in Example 1, the casting using alloy 2 (sample 12, sample C2) and the casting using alloy 3 (sample 13, sample C3). Also made.

The mechanical properties (tensile strength and elongation) of each were measured using the tensile test pieces cut out from each casting. The results thus obtained are summarized in FIG. 10 in association with the amount of Si contained in each alloy.

As is clear from FIG. 10, when the amount of Si in the casting decreases, the primary crystal Al (α-Al) increases while the eutectic decreases, so that the (breaking) elongation increases and the ductility becomes high. However, even when the amount of Si is large, by performing local pressurization, a sufficiently large elongation can be secured with almost no decrease in tensile strength.

Extrapolated from the elongation of sample 12 (Si: 8.5%) and sample 13 (Si: 10%) that were locally pressurized, local pressurization was performed by performing local pressurization even when Si: 12%. It was also found that the elongation can be made higher than that of the sample C1 (Si: 7%) in which cracks were generated at the time of SPR joining without doing so. Therefore, when local pressurization is performed, crack resistance can be ensured even if the amount of Si is at least 12%.

[Example 4]
A casting (sample 31) was also produced in the same manner as in Example 1 using a mold made of a copper alloy (Cr—Ti copper / thermal conductivity: 150 W / mK).

In the case of the mold made of tool steel (SKD61 / thermal conductivity: 29.8 W / mK) used in Example 1, the cooling rate after the completion of pouring was 666 ° C./s. This is the cooling curve shown in FIG. 8, and can be seen from the fact that the molten metal temperature changes from 616 ° C. to 608 ° C. within the time from the start of injection: 0.22 to 0.232 seconds. On the other hand, in the case of a mold made of a copper alloy, the cooling rate was similarly determined to be 1700 ° C./s.

In this way, by changing the material of the mold, it was possible to obtain castings (sample 11 and sample 31) in which the cooling rate was changed by about 2.5 times or more. It is considered that the cooling rate not proportional to the thermal conductivity of each material is due to the thermal resistance existing at the interface between the inner wall surface of the mold and the molten metal (casting).

A three-point bending test was performed on each of the test pieces cut out from the casting of each sample, and the amount of deflection until breaking and the bending strength until breaking were measured. The result is shown in FIG. As is clear from FIG. 11, it was found that by adjusting the cooling rate, the amount of deflection, which is an index value of the plastic deformability at the time of SPR joining, can be increased and the crack resistance at the joint can be improved.

The amount of Si and the amount of Mg dissolved in the primary crystal Al of the casting according to each sample were measured using an electron microprobe device (EPMA). The result is shown in FIG. As is clear from FIG. 12, it was found that the casting (Sample 11) having a relatively low cooling rate and a large amount of deflection had a relatively small amount of solid solution of Si and Mg in α-Al.

Therefore, it was found that by lowering the cooling rate, the solid phase amount of the alloying elements in the primary crystal Al decreases, which can increase the plastic deformation ability of the region (joint portion) to be SPR-bonded and thus the crack resistance. It was.

Claims (8)

An aluminum alloy member for joining, which is made of a cast aluminum alloy and includes a joint portion that is plastically deformed and mechanically joined, and a non-joining portion that is not involved in the joining.
The aluminum alloy contains 6 to 12% of Si with 100% by mass (simply referred to as "%") as a whole.
The junction is HatsuAkiraritsu an existing ratio of the primary crystal aluminum much larger than the said non-joined portion, a ratio of HatsuAkiraritsu of the joint portion for HatsuAkiraritsu of non joint HatsuAkirahi 1 .2 or more,
An aluminum alloy member for joining in which a self-piercing rivet (SPR) can be studded at the joint. Before SL first Akirahi the bonding aluminum alloy member according to claim 1 is 1.3 or more. The aluminum alloy member for joining according to claim 1 or 2, wherein the joint portion has a solid solution amount of an alloy element contained in the primary crystal aluminum less than that of the non-join portion. The aluminum alloy member for joining according to any one of claims 1 to 3, wherein the non-joining portion has a eutectic network structure. The method for manufacturing an aluminum alloy member for joining according to any one of claims 1 to 4, which is made of a cast aluminum alloy and includes a joint portion that is mechanically joined by plastic deformation and a non-joining portion that does not participate in the joining. And
A pouring process in which a molten aluminum alloy containing 6 to 12% of Si is poured into a mold with the whole as 100%.
It is provided with a cooling step of cooling and solidifying the molten metal poured into the mold.
Further, a bonding aluminum alloy comprising a local pressurizing step of locally pressurizing the molten metal in a solid-liquid coexisting state in which primary aluminum is crystallized during the cooling step in a region corresponding to the joining portion. Manufacturing method of parts. The method for manufacturing an aluminum alloy member for bonding according to claim 5, wherein the local pressurization step is performed when the solid phase ratio of the molten metal is 0.25 to 0.95. The method for manufacturing an aluminum alloy member for joining according to claim 5 or 6, wherein the cooling step is performed at a cooling rate of 750 ° C./s or less. The aluminum alloy member for joining according to any one of claims 1 to 4,
With at least one member to be joined to the aluminum alloy member for joining,
A tip portion penetrating the side of the member to be joined is provided with a joining tool for joining the aluminum alloy member for joining and the member to be joined by plastically deforming in the joining portion of the aluminum alloy member for joining .
該接Gogu the self-piercing rivet (SPR) Der Ru composite member.