JP2021188103A - High-strength aluminum alloy quenched coagulate and manufacturing method thereof - Google Patents

Abstract

To provide an aluminum alloy quenched coagulate having small apparent deformation and inside residual stress and its manufacturing method.SOLUTION: An aluminum alloy quenched coagulate molded from a raw material metal containing any one kind of 4 to 30 wt.% of Si, 3 to 6 wt.% of Mg, and 3 to 6 wt.% of Cu, as a main element, one or more kinds of Mn and Cr of 0.3 to 3 wt.% in total weight, 0.3 wt.% or less of Fe, and inevitable impurities. Precipitates and crystallization containing one or more of metals contained in an alloy coexist with an aluminum solid solution which melts at least one or more of Si, Mn, Cr, Mg and Cu, and at least one kind of eutectic crystallized material is present as a discontinuous independent form, or an outer shape of the precipitate is shrinked or solid solubilized.SELECTED DRAWING: None

Description

The present invention relates to a high-strength aluminum alloy quenching solidified body and a method for producing the same, and more particularly to a high-strength aluminum alloy quenching solidified body having suppressed external deformation and internal residual stress and a method for producing the same.

The quenching solidified body of an aluminum alloy has two characteristics: that the solidified structure becomes finer and that a large amount of different atoms are contained as solute atoms between aluminum atoms. Therefore, higher mechanical properties can be obtained as compared with the aluminum alloy molded product obtained by a conventional casting method, for example, a mold casting method, a high pressure casting method, or the like (see, for example, Non-Patent Document 1).

However, when the aluminum alloy is rapidly solidified (at least 500 ° C / s or higher, generally 1000 ° C / s or higher), a large residual stress is generated inside, and in some cases, the outer shape of the product itself is deformed due to distortion. May occur. The following methods are typical of the construction methods in which distortion is likely to occur due to such rapid cooling and solidification.
1) Metal laminating method in which metal powder is instantly melted and instantly solidified while laminating from bottom to top to obtain a molded body 2) Double-roll type strip continuous casting method in which molten metal is directly solidified between metal plates and molded. , Molten metal direct rolling method

In the metal laminating method, in general, the preheating temperature of the base plate is set in order to suppress the distortion of the outer shape (distortion of the aluminum alloy molded body when separated from the base plate, distortion of the aluminum alloy molded body during laminating). The aluminum alloy is laminated while heating at around 200 ° C. As a result, distortion of the outer shape of the aluminum alloy molded body is suppressed (see, for example, Non-Patent Document 2). The temperature at which the metal is laminated while heating the base plate is called the lamination temperature.

In the double-roll strip continuous casting method, since the aluminum alloy is rolled while being solidified, residual stress is generated inside, and deformation or cracking may occur due to subsequent processing or the like. In order to prevent this, the molded product is annealed (see, for example, Patent Document 2).
Further, as a method of both reducing strain and improving strength at the time of laminating an aluminum alloy, there is a method of laminating an aluminum alloy powder to which a small amount of Mn is added, which exhibits a tensile strength equivalent to 450 MPa even at a laminating temperature of 200 ° C. It is possible. The value of this tensile strength is 100 MPa or more higher than that of the conventionally well-known Al-10 wt% Si-0.4 wt% Mg alloy (see, for example, Non-Patent Document 3 and Patent Document 1).

According to the method for producing a rapidly cooled solidified body disclosed in Non-Patent Document 1, by warmly joining powders to each other by extrusion or the like, a molded body having new characteristics can be obtained without causing a large strain in the molded body. be able to. However, since the metal is affected by heat before and during warm molding, the original characteristics of the rapidly cooled solidified body are slightly lost, and the amount of elements that are solid-solved between aluminum atoms is also increased. It will decrease. Further, in order to prevent gas defects from being generated in the warm molded product, a complicated process for removing water in the powder must be performed until the final molded product is obtained.

Non-Patent Document 2 describes that it is possible to suppress the strain of the laminated body by laminating at a stacking temperature of 150 ° C. to 200 ° C. in order to remove the strain. However, by laminating Al-10% by weight Si-0.4% by weight Mg alloy, which is a well-known alloy, in such a temperature range, especially at 200 ° C., an overaging phenomenon occurs and the laminated body softens. The problem that only about 300 MPa of strength, which is the level of aluminum alloys for casting, can be achieved occurs in products having a height of, for example, 50 mm or a lamination time of more than about 10 hours. In particular, since the lower part of the laminated body is constantly affected by heat during the laminating, the overaging phenomenon progresses more than the upper part, and the laminated body softens. Further, in a large product having a long stacking time, for example, a product having a height of 150 mm, the strength is much lower than 300 MPa.

According to Non-Patent Document 3, the overaging phenomenon does not occur even at the laminating temperature of 200 ° C., the high strength exceeding 400 MPa is exhibited in the entire laminated body, and the problem of softening caused by overaging is solved. This is also shown in Patent Document 1 which describes an aluminum alloy laminate to which Mn is added.

However, the present inventors have found that in a rapidly cooled solidified body laminated and molded at a stacking temperature of 70 ° C., in a laminated body having an extremely thin stacking temperature of about 3 mm, the laminated body having a height of 3 mm level is separated from the base plate and at the same time has a large outer shape. Deformation occurs (see Fig. 4), and there is no distortion in a prism with a size of 20 mm × 30 mm × 150 mm, but there is a large residual stress, and if the laminate is cut, the split cross sections will match due to the strain. It has been confirmed that it will disappear (see FIG. 5 (a)).
In FIG. 4, a laminate having a thickness of 3 mm, a width of 10 mm, and a length of 100 mm is laminated on a support having a height of 4 mm, a thickness of 1 mm, and a width of 10 mm.

In order to remove such residual stress, it is easily expected that annealing at a high temperature well exceeding 200 ° C., for example, 300 ° C., which is currently performed, is easily expected, and if it is divided by the above method, it is split. The cross sections match (see FIG. 5 (b)). However, although the residual stress can be removed, the tensile strength is reduced to about 250 MPa, which is lower than the strength of the alloy level for casting, so that it cannot be said to be an appropriate measure for removing the residual stress. This is because the same softening due to aging occurs even in an alloy in which Mn, which exhibits high tensile strength, is added to a 20 × 30 × 50 (mm) prism having a height of 50 mm laminated at 200 ° C. Annealing at high temperature is not suitable.

Further, even in the Mn-added alloy described in Non-Patent Document 3 described above, the higher the stacking height, that is, the longer the stacking time, the more easily the lower portion of the laminate is affected by heat and softened. For this reason, the annealing temperature on the low temperature side in the range of 150 ° C to 200 ° C is compatible with maintaining high strength and suppressing distortion of the outer shape and internal strain (residual stress) of the laminated body. I have no choice but to choose. However, this will still leave residual stress inside.

Patent No. 6393008 Patent No. 5618964

Shibue: Light Metal, 39 (1989), 850-861 Terada et al .: Japan Institute of Light Metals Autumn Meeting (2018) Terada et al .: Japan Institute of Light Metals Autumn Meeting (2019)

It is an object of the present invention to provide an aluminum alloy quenching solidified body which is made under the above circumstances and suppresses external deformation and internal residual stress.
Another object of the present invention is to provide a method for producing an aluminum alloy quenching solid body in which deformation on the outer shape and residual stress inside are suppressed.

In order to solve the above problems, one embodiment of the present invention comprises 4 to 30% by weight of Si as a main element, 3 to 6% by weight of Mg, and 3 to 6% by weight of Cu, whichever is one of them, and the total weight. An aluminum alloy quenching solidified body formed from a raw material metal containing one or more of Mn and Cr having a content of 0.3 to 3% by weight, Fe of 0.3% by weight or less, and unavoidable impurities. Precipitates and crystallization containing one or more of the metals contained in the alloy coexist with an aluminum solid solution into which one or more of Si, Mn, Cr, Mg and Cu are dissolved, and at least one of the crystallizations in the eutectic portion is present. Provided is an aluminum alloy quenching solidified body characterized in that the seeds exist in a discontinuous independent form, or the outer shape of the crystallized material is shrunk or solidified.

Further, in the second aspect of the present invention, in the first aspect described above, the main metal is 4 to 30% by weight of Si, and the raw material metal is further 0.2 to 2% by weight of Mg. It contains 0.2-2% by weight of Cu as needed, exhibits a Vickers hardness of 95 or higher, and at least one of the crystallization is present as a discontinuous independent form, or the outer shape of the crystallization is Provided is an aluminum alloy quenching solidified body characterized by being shrunk or solid solution.

Further, in the third aspect of the present invention, in the above-mentioned first aspect, the main metal is Mg of 3 to 6% by weight, and the raw material metal is further 0.2 to 3% by weight of Si. It contains one or more selected from 0.2 to 0.5% by weight of Cu and 0.5 to 5% by weight of Zn, exhibits a Vickers hardness of 70 or more, and does not contain at least one of the crystallization. Provided is an aluminum alloy quenching solidified body which exists as a continuous independent form or is characterized in that the outer shape of the crystallized product is shrunk or solid solution.

Furthermore, in the fourth aspect of the present invention, in the above-mentioned first aspect, the main metal is Cu in an amount of 3 to 6% by weight, and the raw material metal is further contained in Si in an amount of 0.2 to 2% by weight. And one or more of 0.5-2 wt% Mg, exhibiting a Vickers hardness of 90 or more, at least one of the crystallization is present as a discontinuous independent form, or the outer shape of the crystallization Provided is an aluminum alloy quenching solidified body, which is characterized by shrinking or solid solution.

Further, the fifth aspect of the present invention is the raw material metal according to any one of the first, second, and fourth aspects described above and the raw material metal according to the third aspect, wherein Cu is 0.2. The process of molding a raw metal of less than% by weight by the quenching solidification method, the molded aluminum alloy quenching solidified body is solution-treated (hardened) at a temperature in the range of (alloy melting point -50 ° C) or more and less than the alloy melting point. (Including the step of aging), and if necessary, a step of aging the solution-treated aluminum alloy quenching solidified body at 100 to 270 ° C. Provide a method.

A sixth aspect of the present invention is the step of molding the raw material metal according to the third aspect described above, which contains 0.2 to 0.5% by weight of Cu, by a quenching and solidifying method. , A step of solution-forming (including a step of quenching) the molded aluminum alloy quenching solidified body at a temperature in the range of (alloy melting point -50 ° C) to (alloy solid-phase line temperature), and necessary. The present invention provides a method for producing an aluminum alloy quenching solidified body, which comprises a step of aging the solution-treated aluminum alloy quenching solidified body at 100 to 300 ° C.

In the method for producing an aluminum alloy quenching solidified body according to the fifth and sixth aspects, as the quenching solidification method, a method of quenching and solidifying an aluminum alloy raw material metal at a solidification section cooling rate of 500 ° C./sec or more can be used. can.

According to the present invention, there is provided an aluminum alloy quenching solidified body and a method for producing the same, which suppresses external deformation and internal residual stress as compared with the conventional quenching solidified body.

It is a photographic figure which shows the microstructure of the laminated body which concerns on Example 2 and Comparative Example 5. It is a photographic figure which shows the microstructure of the laminated body which concerns on Example 18 and Comparative Example 19. It is a photographic figure which shows the microstructure of the quenching solid body which concerns on Example 34 and Comparative Example 24. It is a photographic figure which shows the deformation when the thin laminated body is separated from a base plate. It is a photographic figure which shows the deformation when the central part of a laminated body is cut in the laminated direction.

Hereinafter, the aluminum alloy quenching solidified body of the present invention, the aluminum alloy quenching solidified body according to various embodiments thereof, and a method for producing the same will be described.
The aluminum alloy quenching solidified body of the present invention contains 4 to 30% by weight of Si, 3 to 6% by weight of Mg, and 3 to 6% by weight of Cu as main elements, and has a total weight of 0.3 to 3 to 3. It is an aluminum alloy quenching solidified body formed from a raw material metal containing one or more of Mn and Cr which are% by weight, Fe of 0.3% by weight or less, and unavoidable impurities. In such an aluminum alloy quenching solidified body, precipitates and crystallization containing one or more of the metals contained in the alloy coexist with an aluminum solid solution in which one or more of Si, Mn, Cr, Mg and Cu are dissolved. The structure of the eutectic region exists as a discontinuous independent form, or the outer shape of the crystallized material is shrunk or solid solution.

The aluminum alloy quenching solid body of the present invention is obtained by heat-treating a quenching solid body of an aluminum alloy having the above-mentioned composition at a predetermined temperature. It is a quenching solidified body that has excellent mechanical properties that are close to those of the previous quenching solidified body, which is unprecedented in the past. That is, in the quenching solidified body of the present invention, the quenching solidified body is subjected to solution heat treatment (including quenching) and, if necessary, artificial aging treatment. For this reason, there is no deformation on the outside of the quenching solidified body, and the tensile stress as a residual stress disappears on the inside. Is in a state where there is no deformation.

After heat treatment (solution hardening treatment → artificial aging), the quenching solidified body of the present invention exhibits characteristics close to those of the quenched solidified body as it is. This is because the Mn or Cr compound, which exists as a fine compound during quench hardening together with the melted Mn and Cr, further dissolves and diffuses in the aluminum matrix, thereby playing a role in solid solution strengthening and precipitation strengthening. Conceivable. Further, it is considered that this is due to the composite strengthening in which the precipitation strengthening by the added age hardening elements such as Mg, Si and Cu is added.

The aluminum alloy quenching solidified body of the present invention is formed by a quenching solidification method, and examples of the quenching solidification method include a metal laminating method, a double-roll strip continuous casting method, a molten metal direct rolling method, and a direct compression method. can give. Even with the direct compression method, a solidification rate of 500 ° C./sec or higher can be obtained.
The metal laminating method is a method of molding the final product without a mold by laminating the raw metal powder while locally melting and instantly solidifying it. The powder bed fusion bonding method and the deposit method (directional energy deposition method) ) And so on. The aluminum alloy quenching solidified body of the present invention includes a laminated molded body manufactured by any metal laminating method.

The powder bed melt bonding method includes a method using a laser and a method using an electron beam. In order to obtain a molded product having a fine surface roughness, the former method using a laser is advantageous.
The deposit method is a method in which the raw material metal powder is directly injected to a desired portion to be laminated, and the metal powder is laminated while being instantly melted and instantly solidified. Further, the deposit type also includes a method (wire feeding type) in which an alloy wire made of a raw material metal is used instead of powder, and the alloy wire is irradiated with a laser, an electron beam, or the like to be melted and deposited.

Specifically, the aluminum alloy quenching solidified body of the present invention and the method for producing the same achieve the following characteristics.
1) In the laminated molded body that has undergone the laminating process, the residual tensile stress generated inside the laminated body is suppressed as much as possible. The goal is that the split cross section is not distorted even if the laminated body is cut in the stacking direction.

2) In the case of a laminated body, its Vickers hardness indicates 95 or more when Si is contained as a main element, 70 or more when Mg is contained, and 90 or more when Cu is contained. ..
3) The characteristics of 2) above shall be satisfied even in a rapidly cooled solidified body that has been rapidly cooled and solidified at a solidification rate of 500 ° C./sec or higher by another molding method equivalent to the laminating method.

Hereinafter, an aluminum alloy quenching solidified body and a method for producing the same will be described according to various embodiments of the present invention.
The aluminum alloy quenching solidified body according to the first embodiment of the present invention contains one or more of Mn and Cr having a total weight of 0.3 to 3% by weight, Si of 4 to 30% by weight, and 0.2. Aluminum alloy quenching solidified body formed from raw metal containing ~ 2% by weight Mg, 0.2 ~ 2% by weight Cu as needed, 0.3% by weight or less Fe, and unavoidable impurities. It shows a Vickers hardness of 95 or more.

In such an aluminum alloy quenching solid solution, the precipitates and crystallization containing one or more of Al, Mn, Cr, Fe, Mg, Cu and Si are one or more of Si, Mn, Cr, Mg and Cu. Coexists with the aluminum solid solution into which it melts, and at least one of the crystallization represented by eutectic Si exists as a discontinuous independent form, or the outer shape of the crystallization is shrunk or solidified.

Mn and Cr contained in the aluminum alloy quenching solidified body have hardness and tensile strength even after heat treatment (solution heat treatment, artificial aging) performed to reduce the residual stress of the molded body obtained by the quenching solidification method. It is an effective element for maintaining and improving the hardness. If the total weight of Mn and Cr is less than 0.3% by weight, the effect of maintaining / improving the hardness and tensile strength is small, so it is necessary to make it 0.3% by weight or more. On the other hand, even if the total weight of Mn and Cr exceeds 3% by weight, the hardness and tensile strength are not significantly improved, so the total weight is set to 3% by weight or less.

In order to maintain high elongation, it is preferable to keep the total weight of Mn and Cr to about 2% by weight. In the molded quenching solidified body, Mn and Cr exist as a solid solution at the atomic level or as a fine compound with Al or the like. It is considered that by subjecting the aluminum alloy quenching solidified body to solution treatment and artificial aging, a predetermined ratio of Mn and Cr are solid-solved to promote solid solution strengthening, and the artificial aging treatment also promotes age hardening.

The Fe content is 0.3% by weight or less. As the amount of Fe increases, it becomes easier to form crystallization containing Mn and Cr, and even if solution treatment is performed, the morphological change of the crystallization is small and it is difficult for the crystal to dissolve in the aluminum matrix. The hardness after quenching) does not increase, and as a result, the hardness of the quenching solid solution is not high even when precipitation hardening due to artificial aging is taken into consideration, so it is necessary to keep it at 0.3% by weight or less. There is. Further, if the amount of Fe is large, the corrosion resistance also deteriorates, so it is necessary to make it 0.3% by weight or less.

The Si content is 4 to 30% by weight. When the amount of Si is 4% by weight, the Vickers hardness of the quenching solidified body is 115, and when it is less than 4% by weight, the hardness decreases and the target 95 cannot be reached and there is a risk of casting cracking. Must be at least% by weight. Further, Si contributes to the improvement of hardness, while lowering the elongation, so the content is 30% by weight or less.

The content of Mg is 0.2 to 2% by weight. If the amount of Mg is less than 0.2% by weight, it is difficult to maintain the hardness 95, so it is necessary to be 0.2% by weight or more.
The content of Cu added as needed is 0.2 to 2% by weight. Cu is also used as an element for increasing heat resistance, but it is also an element that contributes to improving tensile strength and hardness at room temperature. Cu often forms crystallization with other added elements, but is easily dissolved in the aluminum matrix by solution treatment. If the Cu content is less than 0.2% by weight, improvement in strength and hardness cannot be expected even if heat treatment (solution hardening treatment, artificial aging treatment) is performed, and even if it exceeds 2% by weight, the strength is large. No improvement effect can be expected, and corrosion resistance also decreases.

The Si in the eutectic portion is granulated and exists as a discontinuous independent form. Heat treatment (solution heat treatment) is performed to remove the residual stress of the aluminum alloy quenching solidified body, and as a result, at least one kind of crystallized material represented by eutectic Si becomes a discontinuous independent form or crystallized. The outer shape of the product is shrunk or solid solution.
Further, as the crystallization during quenching and solidification and the precipitate during the artificial aging treatment after the solution treatment, precipitates and crystallization containing one or more of Al, Mn, Cr, Fe, Mg, Cu and Si are found. It is formed. Further, an aluminum solid solution in which one or more of Si, Mn, Cr, Mg and Cu are dissolved is formed during quenching solidification and solution treatment.

The aluminum alloy quenching solidified body according to the second embodiment of the present invention contains one or more of Mn and Cr having a total weight of 0.3 to 3% by weight, Mg of 3 to 6% by weight, and 0. .One or more selected from 2-3% by weight Si, 0.2 to 0.5% by weight Cu, and 0.5 to 5% by weight Zn, and 0.3% by weight or less Fe are inevitable. It is an aluminum alloy quenching solidified body formed from a raw material metal containing impurities, and exhibits a Vickers hardness of 70 or more.

In such an aluminum alloy quenching solid solution, the precipitate and the crystallized product containing two or more kinds of Al, Mn, Cr, Fe, Si, Cu and Mg are one kind of Mg, Mn, Cr, Si and Cu. coexists with aluminum solid solution or blend, KyoAkirabu of Mg 2 _Si, at least one of crystallized substance typified by Cu-Al compound is present as a discontinuous independent form or crystallized substances outer shape It is shrinking or solid solution.

The contents of Mn, Cr, and Fe and their action and effect are the same as those in the first embodiment described above.
In the second embodiment, the Si content is 0.2 to 3% by weight. When the Si content is 0.2% by weight, the hardness of the quenching solidified body is 75, but if it is less than 0.2% by weight, the target of 70 or more cannot be achieved, so the lower limit of the Si content is 0.2. It is% by weight. Further, when the Si content is 1.5% by weight, when the temperature of the solution treatment is, for example, 570 ° C and the temperature of the artificial aging treatment exceeds 160 ° C, the hardness of the quenching solidified body exceeds 90, but the Si content. However, this value does not change significantly even if it exceeds 3% by weight, and the upper limit of the Si content is 3% by weight. Si contributes to the improvement of hardness, but is also effective in preventing casting cracks in the rapidly cooled solidified body. Therefore, 0.2% by weight
It is preferable that the above is included.

The content of Cu is 0.2 to 0.5% by weight. By subjecting the quenching solidified body to solution treatment and then artificial aging treatment, the crystallization containing Cu solidly dissolved during quenching solidification and Cu formed with other additive elements contributes to precipitation hardening after resolidification. This contributes to the improvement of tensile strength and hardness at room temperature. However, if it is less than 0.2% by weight, the improvement effect is small as compared with the case where Cu is not added, so that the lower limit of the Cu content is 0.2% by weight. Further, although the addition of Cu contributes to the improvement of hardness, even if a large amount is added, it rather causes a factor of lowering elongation and corrosion resistance, so the upper limit of the Cu content is 0.5% by weight.

The Zn content is 0.5 to 5% by weight. Zn contributes to the improvement of the tensile strength and hardness of the quenched solid at room temperature by subjecting the quenched solid to a solution treatment. This effect is due to the solid solution of Zn in the matrix containing magnesium. When the Zn content is less than 0.5% by weight, this effect is small, and even if it is added in excess of 5% by weight, a compound containing Zn that cannot be completely dissolved in solid solution is likely to be generated, thereby reducing the elongation. Therefore, the effect is equivalent to that of 5% by weight or less.

The intermetallic _{compound containing Mg 2} Si and / or Cu in the eutectic portion exists as a discontinuous independent form, or the outer shape of the crystallized product is shrunk or solidified. A solution treatment is performed to remove the residual stress of the aluminum alloy quenching solidified body, which _{granulates Mg 2} Si, resulting in an independent form. Further, the intermetallic compound containing Cu is in a solid solution.

In addition, precipitates and crystals containing at least one of Al, Mn, Cr, Fe, Mg, Cu and Si as crystallization during quenching and solidification and precipitates during solutionization treatment and artificial aging treatment after quenching. A product is formed, and an aluminum solid solution is formed in which one or more elements of Si, Mn, Cr, Mg and Cu are dissolved during quenching and solidification, solution treatment and quenching.

The aluminum alloy quenching solidified body according to the third embodiment of the present invention contains one or more of Mn and Cr having a total weight of 0.3 to 3% by weight, Cu of 3 to 6% by weight, and 0. Aluminum alloy quenching solidified body formed from a raw material metal containing 1 or more of 2 to 2% by weight of Si and 0.5 to 2% by weight of Mg, Fe of 0.3% by weight or less, and unavoidable impurities. It shows a Vickers hardness of 90 or more.

In such an aluminum alloy quenching solid solution, the precipitate and the crystallized product containing one or more of Al, Mn, Cr, Fe, Si, Mg and Cu are one of Cu, Mn, Cr, Si and Mg. Whether the above coexists with the melted aluminum solid solution and at least one kind of crystallized material represented by the Cu-Al-based compound in the eutectic part exists as a discontinuous independent form, or the outer shape of the crystallized material is shrunk. It is in solid solution.

The contents of Mn, Cr, and Fe and their action and effect are the same as those in the first embodiment described above.
The content of Cu is 3 to 6% by weight. By subjecting the quenching solidified body to solution treatment and then artificial aging treatment, the solid-dissolved Cu coexists with Mg, which contributes to the improvement of tensile strength and hardness at room temperature by precipitation hardening. However, if it is less than 3% by weight, the improvement effect is small as compared with the case where Cu is not added, so the lower limit of the Cu content is 3% by weight. However, even if it exceeds 6% by weight, there is no significant improvement effect, so the upper limit of the Cu content is 6% by weight.

The content of Mg is 0.5 to 2% by weight. High strength can be obtained by adding Mg in combination with Cu, but the effect is small when it is less than 0.5% by weight, and there is no significant improvement effect when it exceeds 2% by weight.
The Si content is 0.2 to 2% by weight. Si is added for improving heat resistance, and its effect is small when it is less than 0.2% by weight, and there is no big improvement effect when it exceeds 2% by weight.

The eutectic Cu-containing crystallization exists as a discontinuous independent form, or the outer shape of the eutectic is shrunk or solid solution.
Heat treatment (solution treatment) is performed to remove the residual stress of the aluminum alloy quenching solid solution, which causes the intermetallic compound containing Cu in the eutectic part to become a discontinuous independent form, or the outer shape of the crystallized product. Is shrunk, or the crystallized material dissolves in the matrix to form a solid solution.

Further, as in the first embodiment, precipitates and crystallizations containing one or more of Al, Mn, Cr, Fe, Si, Mg, and Cu are formed, and Cu, Mn, Cr, Si, and Mg are formed. One or more of them coexist with an aluminum solid solution into which the eutectic portion contains Cu, and the crystallized product exists as a discontinuous independent form, or the outer shape of the crystallized product is shrunk or solidified.

A fourth embodiment of the present invention is described in the aluminum alloy quenching solidified body formed by molding the raw metal used in the above first and third embodiments by a quenching solidification method and the second embodiment. This is a method for producing an aluminum alloy quenching solidified body, which comprises a solution treatment of a quenching solidified body having Cu of less than 0.2% by weight as a raw material metal. The solution treatment is performed at a temperature in the range of (melting point of the alloy -50 ° C) or higher and lower than the melting point of the alloy, and if necessary, the solution-treated quenching solidified body is aged at 100 to 270 ° C. ..

A fifth embodiment of the present invention is an aluminum alloy quenching solidified body obtained by a quenching solidification method using a raw material metal containing 0.2 to 0.5% by weight of Cu, which is used in the second embodiment described above. This is a method for producing an aluminum alloy quenching solid body, which comprises a solution treatment. The solution treatment is carried out at a temperature in the range of (melting point of alloy -50 ° C) to (solid phase temperature of alloy), and the quenched quenching solidified body is aged at 100 to 300 ° C as necessary. To.

In this way, by subjecting the quenching solidified body to solution treatment and, if necessary, artificial aging treatment, the residual stress is reduced, and conventionally known Al-Si-Mg-based alloys and Al-Mg-Si-based alloys are used. It is possible to obtain higher hardness and tensile strength than the quenching solidified body of.

For example, when an Al-10Si-0.4Mg alloy known as a metal laminating alloy is laminated at 200 ° C. to a height of 150 mm, the laminating time becomes 100 hours, and in such a long laminating time, the laminated body becomes Due to the large heat effect, the Vickers hardness of the lower part of the laminate is less likely to exceed 70. However, high Vickers hardness can be obtained by subjecting a laminate containing one or more of Mn and Cr to a solution treatment.

According to the fourth embodiment of the present invention, strain can be reduced both inside and outside the molded body, and high hardness and tensile strength that can never be obtained at a stacking temperature of 200 ° C. can be obtained.
The reason why the solution heat treatment temperature is set to the melting point of -50 ° C. or higher is that the solute element is supersaturated and solid-solved in the Al matrix of the parent phase, and the solute element is strengthened by the subsequent artificial aging. In addition, this treatment can make the eutectic into a discontinuous independent form. If it is lower than this temperature, it takes a lot of time to dissolve the solid solution, so that the desired hardness cannot be obtained.
As the temperature of the aging treatment, it is preferable to appropriately select a temperature at which high hardness is developed by combining precipitation hardening with an additive element with solid solution strengthening and precipitation strengthening of Mn and Cr.
In the quenching solidified body of the fourth embodiment in which Cu is less than 0.2% by weight, the aging treatment is performed at 100 to 270 ° C. because the aging hardening takes too long at less than 100 ° C., and 270 ° C. This is because the maximum hardness decreases due to overaging.

Al-10Si-0.7Mg-0.6Mn alloy was laminated at 160 ° C., if the material and then examined to hold 1 hour while raising the temperature by 10 ° C., softened by the coarsening of _Mg 2 Si to first 200 ° C. However, after the subsequent stabilization, the hardness decreases again when the temperature exceeds 270 ° C. It is considered that this is due to the precipitation of Mn.

Further, in the fifth embodiment containing 0.2 to 3% by weight of Cu, the aging treatment is performed at 100 to 300 ° C. because the maximum hardness decreases due to overaging when the temperature exceeds 300 ° C.
In the fifth embodiment, the temperature of the solution treatment is in the range of (alloy melting point −50 ° C.) to (alloy solid phase line temperature), and the upper limit temperature is high because it is crystallized by non-equilibrium solidification. This is because if the alloy is first melted and then held at a temperature below the solidus line, the mechanical properties are rather improved.

In the quenching and solidifying method according to the fourth and fifth embodiments of the present invention, the aluminum alloy raw material metal can be quenched and solidified at a cooling rate in a solidification section of 500 ° C./sec or higher.
Further, in a quenching solidified body containing one or more of Mn and Cr and containing any of Si, Mg, and Cu as the main elements, if the quenching solidified body has a function other than hardness, other additive elements may be used. Can be added. For example, when heat resistance is required, the addition of Ni is effective when Si or Cu is contained as the main element.

Further, when a large amount of Mg is contained, particularly when Mg is contained as a main element, the quenching solidified body may be oxidized and discolored during the solution treatment unless the atmosphere is an inert atmosphere. Therefore, it is effective to add Be. For example, the addition amount is 0.001 to 0.003% by weight level.
Further, when a large amount of Mg is contained, there is a possibility of casting cracking depending on the shape of the product. The addition of Si is effective as described above, but Ti and Zr as crystal micronizing agents are also effective. The range of 0.1% to 0.5% is suitable.
Further, adding Sc having a high precipitation hardening ability at an upper limit temperature of 270 ° C. or lower capable of maintaining solid solution strengthening and precipitation strengthening by Mn is expected to have a combined effect.

Hereinafter, examples of the present invention will be described in comparison with comparative examples.
As the molding method used in this example, a metal laminating method and a direct compression method using a Cu plate were applied. For the former, the laser laminating method was used. The latter adopted a method of [quenching and solidifying by sandwiching a molten metal between two Cu plates], which is considered to be equivalent in principle to the double-roll strip continuous casting method.
Examples 1-16, Comparative Examples 1-15
Using Al alloy powder (average particle size: 35 μm) having the compositions shown in Tables 1 and 2 below, 27 types of laminated molded bodies (Example 1) were used by a laser laminating method at the laminating temperatures shown in Tables 1 and 2 below. ~ 14, Comparative Examples 1 to 13) were prepared.

Among these molded bodies, Examples 1 to 14 and Comparative Examples 3 and 9 to 13 were maintained at the solution treatment temperature, water-quenched and artificially aged (T6) under the conditions shown in Tables 1 and 2 below. Processing) was performed. However, only in Example 1, natural aging (T4 treatment) was performed instead of artificial aging treatment. In Comparative Examples 1, 2, 4, 5, and 8, none of the solution treatment retention, water quenching, and artificial aging treatment was performed. For Comparative Examples 6 and 7, solution retention and water quenching were not performed, and only artificial aging treatment (T5 treatment) was performed.

The condition of water quenching is to put it in water at room temperature and adjust it to the temperature of the water. The time required for cooling from the solution treatment temperature (around 500 ° C) is approximately 3 seconds or less, preferably 2 seconds or less. T4 treatment: Keep at the solution treatment temperature, quench with water, and leave in the air for natural aging T6. Treatment: Process of maintaining at the solution treatment temperature, quenching with water, and then performing artificial aging treatment T5 treatment: Treatment of performing artificial aging on the material that remains solidified

Similarly, using the Al alloy having the compositions shown in Tables 1 and 2 below, a direct compression method using a Cu plate (directly compresses the molten metal placed on the lower Cu mold with the upper Cu mold, and directly. Four types of molded bodies (Examples 15 and 16, Comparative Examples 14 and 15) are produced by the same level of 1000 ° C./s as the rolling method and the metal laminating method and having a cooling rate of 500 ° C./s or more at the latest). )created. Among these laminated bodies, Examples 15 and 16 and Comparative Example 15 were subjected to solution retention, water quenching, and artificial aging treatment under the conditions shown in Table 1 below.

Among these molded bodies, with respect to Examples 1 to 14 and Comparative Examples 1 to 13, the tensile strength (MPa), elongation (%), and Vickers hardness (HV) of 5 mm from the bottom of the flat plate column laminate. ) Was measured, and the external strain of the prismatic laminate was observed. Further, in Examples 15 and 16 and Comparative Examples 14 and 15, the Vickers hardness (HV) at the center of the thickness cross section of the disc-shaped molded product having a thickness of 0.5 mm was measured. The results are shown in Tables 3 and 4 below.

Tables 3 and 4 below show the effects of Mn, Cr addition and heat treatment (T4, T5, T6) of the Al—Si—Mg based alloy molded product.
As shown in Table 3 below, in Examples 1 to 14, an Al—Si—Mg-based alloy to which Mn or Cr is added and the amounts of Si, Mg, Mn, and Cr are all within the range of the present invention. It is a rapidly cooled solidified product, which is kept at the solution treatment temperature, then quenched with water, and artificially aged as necessary. All of these quenching solids maintain high tensile strength and elongation, and exhibit a hardness of 98 or more.

It should be noted that the reason why the high elongation is shown is that the eutectic Si becomes a discontinuous independent form as shown in Table 3 below because it is subjected to water quenching and aging treatment (T6 treatment) after being maintained at the solution treatment temperature. This is due to the fact that the outer shape of the Al-Cu-based compound in the eutectic part has a contracted structure. Further, since the solution treatment is performed, distortion does not occur even if the central portion of the prismatic molded body (20 × 30 × 150 mm) is cut in the stacking direction, and the cut opening is as shown in FIG. 5 (c). The part became 0 mm.

Comparative Examples 1 to 13 are quenching solidified bodies by a metal laminating method. Of these comparative examples, Comparative Examples 1, 2, 4, 5, and 8 are as built materials that have not been heat-treated, and Comparative Examples 6 and 7 have been subjected to T5 treatment, that is, aging treatment. However, it has not been solution-treated (T5 treatment). Therefore, as shown in Table 4 below, the eutectic Si does not have a discontinuous independent form structure, but is a linked fibrous structure. In Comparative Examples 3 and 9 to 13, since the T6 treatment is performed, the eutectic Si has a discontinuous independent form structure.

Comparative Example 1 is a typical metal laminated alloy, and since the lower part of the laminate is heat-affected due to the long-term lamination over 4 days, the hardness of the lower part is 90 and the cast alloy Al-7Si-0. It is a 3Mg alloy level and not high. Comparative Example 2 is a case where the stacking temperature is further raised to 200 ° C. in order to prevent distortion of the laminated body, and the hardness is further lowered to 80. Comparative Example 3 in which this laminate was treated with T6 has a hardness of only 90.

In Comparative Examples 1 and 2, there is no external distortion even after the laminated body is separated from the surface plate, but when cut in parallel with the laminated direction, the laminate is deformed and has an opening of 0.8 mm as shown in FIG. 5 (a). Was observed. Incidentally, the residual stress measured by using X-rays from the top side of the laminated body of Comparative Example 1 showed a high tensile stress of 152 MPa. On the other hand, in Comparative Example 3 treated with T6, the tensile stress disappeared and the residual stress of the compressive stress (-50 MPa) was obtained.

In Comparative Examples 4 to 8, 0.6 to 1.5% by weight of Mn was added to the Al-7Si-0.7Mg alloy, but the laminate was maintained at the solution heat treatment temperature and was water-quenched. Not done. Some of them show considerably high hardness due to the difference in stacking temperature and the difference in hardness due to the difference in heat treatment (aging treatment, none), but when the laminate is cut, it is deformed by the stress remaining inside. ..
FIG. 1 shows the microstructure of the laminated body after the heat treatment according to Example 2 and the microstructure of the laminated body not subjected to the heat treatment according to Comparative Example 5. By the solution treatment, it can be seen that the fibrous structure, which is so fine that the eutectic Si cannot confirm its morphology, is changed to a granulated structure.

In Comparative Example 9, since the amount of Si is as large as 31% by weight, the hardness is high, but the elongation is considerably low. Since the amount of Mn in Comparative Example 10 is 3.4% by weight, which exceeds 3% by weight, the mechanical properties are lower than those of Example 6 in which the amount of Mn is 2.8% by weight. Since the amount of Mg in Comparative Example 11 is 2.5% by weight, which is outside the range of the present invention, the hardness of Comparative Example 11 is lower than that of Example 9 in which the amount of Mg is 1.7% by weight. In Comparative Example 12, the amount of Mg is as low as 0.1% by weight, so that the hardness and the tensile strength are low. Since the amount of Cr in Comparative Example 13 is as large as 3.5% by weight, the hardness and tensile strength are lower than those in Example 13 in which the amount of Cr is 2.5% by weight.

Regarding the quenching solidified body obtained by the direct compression method using a Cu plate, Examples 15 and 16 show high hardness of 110 and 100 by solid solution strengthening with Mn or Cr, but comparative examples containing no Mn or Cr. The hardness of 14 and 15 is lower than that. Comparative Example 14 without T6 treatment shows a hardness of 85, which is about 20 higher than that of a general mold casting product without heat treatment, but even if T6 treatment is performed as in Comparative Example 15. It stays at 90, which is the same hardness as the mold casting material.

Examples 17-21, Comparative Examples 16-19
Using Al alloy powder (average particle size: 35 μm) having the composition shown in Table 5 below, seven types of laminated molded bodies (Examples 17 to 21, Comparative Example 18) were used by a laser laminating method at the laminating temperature shown in Table 5 below. ~ 19) was created. Among these laminated bodies, Examples 17 to 21 were subjected to water quenching and artificial aging treatment after being maintained at the solution treatment temperature under the conditions shown in Table 5 below.

Similarly, using the Al alloy having the composition shown in Table 5 below, two types of molded bodies (Comparative Examples 16 and 17) were prepared by a mold casting method.
From these molded bodies, a flat plate column molded body having a size of 10 mm × 100 mm × 150 mm and a prismatic molded body having a size of 20 mm × 30 mm × 150 mm were cut out.

Among these molded bodies, the tensile strength (MPa), elongation (%), and Vickers hardness (HV) of the flat plate column molded body were measured 5 mm from the bottom, and the external strain was observed for the square column molded body. The results are shown in Table 6 below.
Table 6 below shows the effects of Mn and Cr addition and solution formation / quenching of the Al—Mg—Si alloy molded product.

Examples 17 and 18 are Al—Mg—Si alloy laminates containing Mn, and Example 19 is an Al—Mg—Si alloy laminate containing Cr. All of these are heat-treated at a high solution treatment temperature and a high aging treatment temperature. As a result, in addition to the solid solution strengthening and precipitation strengthening by Mn and Cr, the eutectic Mg ₂ Si can be made into a discontinuous independent form, and the precipitation hardening of Mg—Si can be promoted. As a result, it is possible to maintain the hardness of the laminated body as it is and to eliminate the deformation after cutting the laminated body due to the residual stress.

In Example 20, Cu is added instead of Si contained in Example 18, and in Example 21, Zn is further added to the composition of Example 18. These are aimed at precipitation hardening of Cu—Al compounds and solid solution hardening of Zn, respectively, and show high hardness by T6 treatment.

Comparative Example 16 is a mold casting material using a general casting alloy, which has a low hardness of 60 and a high elongation. In Comparative Example 17, the hardness is improved by adding Si to the alloy of Comparative Example 16. Comparative Example 18 is an alloy having the same composition as that of Comparative Example 17, but exhibits high hardness because it is a metal laminate which is a rapid solidified body. However, if the laminate is not heat-treated, it will be deformed by cutting due to the stress remaining inside the material. Comparative Example 19 has a higher hardness than Comparative Example 18 because it has a larger amount of Mn, but similarly, if the laminate is not heat-treated, it will be deformed by cutting due to the stress remaining inside the material. In addition, the residual stress at the top of the laminate is also high.
FIG. 2 shows the microstructure of the laminated body after the heat treatment according to Example 18 and the microstructure of the laminated body not subjected to the heat treatment according to Comparative Example 19. It can be seen that the amorphous eutectic Mg ₂ Si is changed to a granulated structure by the solution treatment.

Examples 22-28
Using the molten Al alloy having the composition shown in Table 5 below, seven kinds of rapidly cooled solidified bodies (Examples 22 to 28) were prepared by a direct compression method using a Cu plate.
Examples 22 and 23 show the results of a direct compression method using a Cu plate in which Si and Cu are added to an Al-4Mg-0.5Mn-based alloy, respectively. It was found that the hardness values were almost the same as those of the metal laminates of the same component (Examples 18 and 20), and the quenching solidified body of the same method and the quenching solidified body of the metal lamination method solidified at the same cooling rate. It can be seen that it depends on the result.

Examples 24, 25, 26, 27, and 28 are quenching solids having a chemical composition in the range of the present invention containing 4 to 5% of Mg, and are produced by a direct compression method. All of them have a Vickers hardness of 70 or more as shown in Table 6 below by being kept at the solution heat treatment temperature, water-quenched, and artificially aged. Further, Example 24 contains 0.5% of Mn and shows a Vickers hardness of 70 or more, and the quenching solids of Examples 25, 26, 27 and 28 each contain 0.2% of Cu in addition to Mn. , Zn is 0.5%, Zn is 2.5%, and Zn is 5%, all of which have a Vickers hardness of 80 to 120.

Examples 29 to 33, Comparative Examples 20 to 23
Using Al alloy powder (average particle size: 35 μm) having the composition shown in Table 7 below, 9 types of laminated molded bodies (Examples 29 to 33, Comparative Example 20) were used by a laser laminating method at the laminating temperature shown in Table 7 below. ~ 23) was created. Among these laminated bodies, Examples 29 to 33 were maintained at the solution heat treatment temperature, water-quenched, and artificially aged or naturally aged under the conditions shown in Table 7 below.

From these laminated molded bodies, a flat column column laminated molded body having a size of 10 mm × 100 mm × 150 mm and a prismatic laminated molded body having a size of 20 mm × 30 mm × 150 mm were cut out.
Among these laminated molded bodies, the tensile strength (MPa), elongation (%), and Vickers hardness (HV) of 5 mm from the bottom of the flat column laminated molded body were measured, and the external strain was observed for the square column laminated molded body. .. The results are shown in Table 8 below.
Table 8 below shows the effects of the Al—Cu alloy laminated molded body by adding Mn and Cr and keeping it at the solution heat treatment temperature, water quenching, artificial aging, or natural aging.

In Examples 29 to 33, solution treatment, quenching, and subsequent artificial aging or natural aging are performed at about 500 ° C. Therefore, there is no deformation after cutting caused by the stress remaining inside the material. Further, there is no tensile stress in the residual stress of the top of the laminated molded body. Furthermore, the mechanical properties of the laminated product are not reduced, and the hardness and tensile strength are equal to or higher than those of the laminated product. These are caused by the precipitation strengthening of the precipitate containing Cu, as well as the solid solution strengthening by Mn and Cr.
Comparative Examples 20 to 23 are laminated molded bodies having a composition within the range of the present invention, and show a high hardness of 100 or more, but residual stress is not removed because they have not been solution-treated or quenched. , Deformation after cutting the laminate has occurred.

Examples 34 to 37, Comparative Example 24
Using the molten Al alloy having the composition shown in Table 7 below, four types of rapidly cooled solidified bodies were prepared by a direct compression method using a Cu plate.
All of these quenching solidified bodies show a Vickers hardness of 90 or more, as shown in Table 8 below, by holding at the solution heat treatment temperature, quenching with water, and performing artificial aging.

FIG. 3 shows the microstructure of the quenching solidified body of Example 34 (right side) and the microstructure of the quenching solidified body made of the Cu plate not subjected to the heat treatment according to Comparative Example 24 (left side). From FIG. 3, in the quenching solidified body (left side) of Comparative Example 24, a continuous Cu compound was observed, whereas in the quenching solidified body (right side) of Example 34, the continuous Cu compound was formed by solution treatment. It can be seen that the morphology has shrunk and is discontinuous. In addition, the presence of Mn-based compounds can be confirmed.

Examples 35 and 36 contain about 1.5% of Mn, and each of Cu and Mg contain 3% and 0.5% of the lower limit values, respectively. As shown in Table 8 below, the Vickers hardness is Shows about 100. Example 37 contains the same amounts of Cu and Mg as in Example 34, but the amount of Mn is 0.5%, which is close to the lower limit, and the Vickers hardness is slightly reduced, but shows a high value of 142.

Claims (7)

As the main elements, any one of 4 to 30% by weight Si, 3 to 6% by weight Mg, and 3 to 6% by weight Cu, and Mn and Cr having a total weight of 0.3 to 3% by weight. An aluminum alloy quenching solidified body formed from a raw material metal containing one or more, 0.3% by weight or less of Fe, and unavoidable impurities, and a precipitate containing one or more of the metals contained in the alloy. The crystallization coexists with an aluminum solid solution into which one or more of Si, Mn, Cr, Mg and Cu are dissolved, and at least one crystallization of the eutectic portion exists as a discontinuous independent form or a crystallization. An aluminum alloy quenching solidified body characterized in that the outer shape of the aluminum alloy is shrunk or solidified. The main metal is 4 to 30% by weight of Si, and the raw material metal further contains 0.2 to 2% by weight of Mg and, if necessary, 0.2 to 2% by weight of Cu, and is 95 or more. The aluminum according to claim 1, wherein at least one of the crystallization is present in a discontinuous independent form, or the outer shape of the crystallization is shrunk or solid solution. Alloy quenching solid solution. The main metal is 3 to 6% by weight of Mg, and the raw material metal is further 0.2 to 3% by weight of Si, 0.2 to 0.5% by weight of Cu, and 0.5 to 5% by weight. Contains one or more selected from% Zn, exhibits a Vickers hardness of 70 or more, and at least one of the crystallization is present as a discontinuous independent form, or is the outer shape of the crystallization shrinking? The aluminum alloy quenching solidified body according to claim 1, which is a solid solution. The main metal is 3 to 6% by weight of Cu, and the raw material metal further contains 0.2 to 2% by weight of Si and 0.5 to 2% by weight of Mg, and 90 or more. The aluminum according to claim 1, wherein at least one of the crystallization is present in a discontinuous independent form, or the outer shape of the crystallization is shrunk or solid solution. Alloy quenching solid solution. A step of molding the raw material metal according to any one of claims 1, 2 and 4, and the raw material metal according to claim 3 having a Cu content of less than 0.2% by weight by a quenching solidification method. A step of solution-forming (including a step of quenching) the aluminum alloy quenching solidified body at a temperature in the range of (the melting point of the alloy -50 ° C) or higher and lower than the melting point of the alloy, and if necessary, the solution. A method for producing an aluminum alloy quenching solidified body, which comprises a step of aging the converted aluminum alloy quenching solidified body at 100 to 270 ° C. A step of molding a raw metal containing 0.2 to 0.5% by weight of Cu, which is the raw metal according to claim 3, by a quenching solidification method, a molded aluminum alloy quenching solidified body (of an alloy). A step of solution treatment (including a step of quenching) at a temperature in the range of (melting point -50 ° C) to (solid phase line temperature of the alloy), and, if necessary, a solution-treated aluminum alloy quenching solidified body. A method for producing an aluminum alloy quenching solidified body, which comprises a step of aging treatment at 100 to 300 ° C. The method for producing an aluminum alloy quenching solidified body according to claim 5 or 6, wherein the quenching solidification method is a method for quenching and solidifying an aluminum alloy raw material metal at a solidification section cooling rate of 500 ° C./sec or higher.

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