Aluminum alloy for casting and aluminum castings cast using the same

Abstract

This aluminum alloy for casting contains 1.0-10.0 mass% of Ni, 8.01-18.0 mass% of Cu and 0.01-0.75 mass% of Mn, the remainder being Al and unavoidable elements.

Description

[Technical field]

[0001] The present invention relates to an aluminum alloy for casting and an aluminum casting produced using the same. [Background technology]

[0002] Patent Document 1 (WO 2015 / 152133) discloses an Al-Si-Mg-based aluminum alloy for casting, which consists, by mass, of 12.0 to 14.0% Si, 1.5 to 4.0% Mg, 0.10% or less Mn, and the balance being Al and unavoidable impurities, and which has excellent specific rigidity, strength, and ductility, and a cast member made of the same. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 152133 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for aluminum alloys for casting that have high rigidity and excellent tensile strength. [Means for solving the problem]

[0005] One aspect of the present invention is a casting aluminum alloy containing 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.75 mass % Mn, and the balance being Al and unavoidable elements.

[0006] According to this aluminum alloy for casting, by setting the Ni content to 1.0 to 10.0 mass%, a Ni-based intermetallic compound phase, which is a long-flak intermetallic compound phase resulting from Ni, can be dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, by setting the Cu content to 8.01 to 18.0 mass%, a Cu-based intermetallic compound phase, which is an intermetallic compound phase resulting from Cu, can be crystallized in a mesh-like shape around the Ni-based intermetallic compound phase. Therefore, by allowing the Ni-based intermetallic compound phase and the Cu-based intermetallic compound phase with different crystallization regions to coexist, the rigidity of the aluminum alloy can be further improved. Furthermore, the Cu-based intermetallic compound phase forms a mesh-like network around the Ni-based intermetallic compound phase, which can improve the tensile strength of the aluminum alloy. Furthermore, by setting the lower limit of the Mn content to 0.01 mass%, a Mn-based intermetallic compound phase, which is an intermetallic compound phase resulting from Mn, can be crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be easily improved. Furthermore, by setting the upper limit of the Mn content to 0.75 mass %, coarsening of the Mn-based intermetallic compound phase as a hard phase is suppressed, and embrittlement of the aluminum alloy is easily suppressed, which makes it easy to suppress a decrease in the tensile strength of the aluminum alloy.

[0007] The aluminum alloy for casting may contain 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.80 mass % Fe, with the balance being Al and unavoidable elements.

[0008] According to this aluminum alloy for casting, by setting the Ni content to 1.0 to 10.0 mass%, the Ni-based intermetallic compound phase can be dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, by setting the Cu content to 8.01 to 18.0 mass%, the Cu-based intermetallic compound phase can be crystallized in a network around the Ni-based intermetallic compound phase. Therefore, by allowing the Ni-based intermetallic compound phase and the Cu-based intermetallic compound phase with different crystallization regions to coexist, the rigidity of the aluminum alloy can be further improved. Furthermore, the Cu-based intermetallic compound phase forms a network around the Ni-based intermetallic compound phase, so that the tensile strength of the aluminum alloy can be improved. Furthermore, by setting the lower limit of the Fe content to 0.01 mass%, the Fe-based intermetallic compound phase, which is an intermetallic compound phase caused by Fe, can be crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be easily improved. Furthermore, by setting the upper limit of the Fe content to 0.80 mass %, coarsening of the Fe-based intermetallic compound phase as a hard phase is suppressed, and embrittlement of the aluminum alloy is easily suppressed, which makes it easy to suppress a decrease in the tensile strength of the aluminum alloy.

[0009] In the above aluminum alloy for casting, the Ni content is preferably 3.0 to 10.0 mass%. By setting the lower limit of the Ni content to 3.0 mass%, the Ni-based intermetallic compound phase can be more dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be further improved.

[0010] In the above-mentioned aluminum alloy for casting, it is preferable that the Cu content [Cu] and the Ni content [Ni] satisfy the following condition (1). 10.0≦[Cu]+0.87[Ni]≦23.5 (1)

[0011] The above aluminum alloy for casting preferably further contains 5.0 to 20.0 mass% Si. By making the Si content 5.0 to 20.0 mass%, the Si phase can be dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, by making the Ni content 1.0 to 10.0 mass%, the Ni-based intermetallic compound phase can be crystallized around the Si phase. Furthermore, by making the Cu content 8.01 to 18.0 mass%, the Cu-based intermetallic compound phase can be crystallized in a mesh-like shape around the Si phase and the Ni-based intermetallic compound phase. Therefore, by making the Si phase, the Ni-based intermetallic compound phase, and the Cu-based intermetallic compound phase, which have different crystallization regions, coexist, the rigidity of the aluminum alloy can be further improved.

[0012] In the above aluminum alloy for casting, the Si content is preferably 5.0 to 14.5 mass%. By setting the upper limit of the Si content to 14.5 mass%, coarsening of the Si phase during the solidification process of the aluminum alloy is suppressed, and embrittlement of the aluminum alloy is easily suppressed. Therefore, the tensile strength of the aluminum alloy is easily improved.

[0013] In the above-mentioned aluminum alloy for casting, it is preferable that the Si content [Si], the Cu content [Cu] and the Ni content [Ni] satisfy the following condition (2). 30.0≦[Si]+0.94[Cu]+2.02[Ni]≦42.5 (2)

[0014] The above-mentioned aluminum alloy for casting preferably further contains 0.0001 to 0.1 mass% P. By making the P content 0.0001 to 0.1 mass%, AlP (aluminum phosphide) generated in the aluminum alloy acts as a heterogeneous nucleus of primary crystal Si, so that the primary crystal Si can be made fine. Therefore, primary crystal Si can be easily uniformly dispersed and crystallized in the aluminum alloy. Therefore, it is easy to suppress the variation in stiffness and tensile strength in the aluminum alloy.

[0015] The above aluminum alloy for casting preferably further contains 0.01 to 3.0 mass% of Mg. By making the Mg content 0.01 to 3.0 mass%, it is possible to precipitate an Mg-based intermetallic compound phase, which is an intermetallic compound phase originating from Mg, by aging treatment. This makes it possible to further improve the tensile strength of the aluminum alloy.

[0016] In the above aluminum alloy for casting, the Cu content is preferably 9.0 to 15.5 mass %.

[0017] Another aspect of the present invention is an aluminum casting produced by using the above-mentioned aluminum alloy for casting, which has high rigidity and excellent tensile strength.

[0018] Another aspect of the present invention is an aluminum alloy powder for additive manufacturing, which contains 1.0 to 10.0 mass% Ni, 8.01 to 18.0 mass% Cu, 0.01 to 0.75 mass% Mn, and the balance being Al and unavoidable elements. The aluminum alloy powder for additive manufacturing may contain 1.0 to 10.0 mass% Ni, 8.01 to 18.0 mass% Cu, 0.01 to 0.80 mass% Fe, and the balance being Al and unavoidable elements.

[0019] Another aspect of the present invention is a layered object produced by layering using the aluminum alloy powder for layered manufacturing. A layered object having high rigidity and excellent tensile strength can be provided. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a diagram showing the compositions, values ​​of condition (1), values ​​of condition (2), Young's modulus, and tensile strength of examples and comparative examples of casting aluminum alloys according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing the observation results of the structure of a test piece of a casting aluminum alloy according to Comparative Example 1. [Diagram 3] FIG. 2 is a diagram showing the observation results of the structure of a test piece of the casting aluminum alloy according to Example 1. [Figure 4] FIG. 4 is a diagram showing the observation results of the structure of a test piece of the casting aluminum alloy according to Example 2. [Diagram 5] FIG. 11 is a diagram showing the observation results of the structure of a test piece of the casting aluminum alloy according to Example 3. [Figure 6] FIG. 13 is a diagram showing the observation results of the structure of a test piece of the casting aluminum alloy according to Example 8. [Figure 7] FIG. 13 is a diagram showing the observation results of the structure of a test piece of the casting aluminum alloy according to Example 10. [Figure 8] FIG. 13 is a diagram showing the observation results of the structure of a test piece of a casting aluminum alloy according to Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, with reference to the attached drawings, several embodiments to which the composition (content of component elements) of the aluminum alloy disclosed in the present application (hereinafter referred to as "the composition") can be applied will be described. One example of an embodiment to which the composition can be applied is an aluminum alloy composition having the composition (hereinafter referred to as "the aluminum alloy composition"). Another example of an embodiment to which the composition can be applied is an article manufactured using the aluminum alloy composition (hereinafter referred to as "the article").

[0022] Examples of the aluminum alloy composition include aluminum alloys for casting, aluminum alloy powders for additive manufacturing, welding materials, and thermal spraying materials. Examples of the present article include aluminum castings cast using aluminum alloys for casting, laminated objects produced by additive manufacturing using aluminum alloy powders for additive manufacturing, objects produced by welding materials, and objects produced by thermal spraying materials. Below, several embodiments of the aluminum alloys for casting (first to fifteenth embodiments) will be described, but the compositions in these several embodiments can also be applied to aluminum alloy powders for additive manufacturing, welding materials, and thermal spraying materials. The present invention is not limited to the following embodiments (first to fifteenth embodiments).

[0023] <First embodiment> The aluminum alloy for casting according to the first embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.75 mass % Mn, and the balance being Al and unavoidable elements.

[0024] In this embodiment, "casting" includes casting by various casting methods such as sand casting, metal mold casting, and die casting. In addition, "aluminum alloy" means an alloy containing an aluminum phase as a main phase. Therefore, "casting aluminum alloy" means an aluminum alloy cast by various casting methods such as sand casting, metal mold casting, and die casting. "% by mass" of an element means the percentage of the mass of the element with respect to the mass of the casting aluminum alloy. For example, the expression "elements of A to B% by mass" means that the mass% of the element is A% or more and B% or less. "Remainder" means components other than the listed elements among the components constituting the casting aluminum alloy. For example, the expression "a casting aluminum alloy including Ni, Cu, Mn, and the remainder being Al and unavoidable elements" means that components other than Ni, Cu, and Mn among the components constituting the casting aluminum alloy are Al and unavoidable elements. The same applies to the following embodiments.

[0025] (Ni: Nickel) The aluminum alloy for casting according to the first embodiment contains 1.0 to 10.0% by mass of Ni. In the aluminum alloy for casting according to the present embodiment, a Ni-based intermetallic compound phase, which is a long-flak-shaped intermetallic compound phase resulting from Ni, is dispersed and crystallized in the aluminum alloy, for example, as a primary crystal. Since the lower limit of the Ni content is 1.0% by mass, the amount of the Ni-based intermetallic compound phase produced can be increased. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, since the upper limit of the Ni content is 10.0% by mass, the coarsening of the Ni-based intermetallic compound phase during the solidification process of the aluminum alloy can be suppressed. Therefore, for example, a situation in which a crack develops along the long-side-shaped Ni-based intermetallic compound phase can be easily suppressed. Therefore, a decrease in the tensile strength of the aluminum alloy can be suppressed. The same applies to the following embodiments.

[0026] (Cu: Copper) The casting aluminum alloy of the first embodiment contains 8.01 to 18.0 mass% Cu. In the casting aluminum alloy of this embodiment, the Cu-based intermetallic compound phase, which is an intermetallic compound phase caused by Cu, is crystallized around the Ni-based intermetallic compound phase in a mesh-like shape as a eutectic with Al, for example. Since the lower limit of the Cu content is 8.01 mass%, the amount of the Cu-based intermetallic compound phase produced can be increased. Therefore, the rigidity of the aluminum alloy can be improved. Moreover, since the upper limit of the Cu content is 18.0 mass%, an excessive increase in the Cu-based intermetallic compound phase as a hard phase can be suppressed. Therefore, the embrittlement of the aluminum alloy can be suppressed. Therefore, the decrease in the tensile strength of the aluminum alloy can be suppressed. The same applies to the following embodiments.

[0027] (Mn: Manganese) The aluminum alloy for casting according to the first embodiment contains 0.01 to 0.75% by mass of Mn. Since the lower limit of the Mn content is 0.01% by mass, a Mn-based intermetallic compound phase, which is an intermetallic compound phase resulting from Mn, can be crystallized in the aluminum alloy. This improves the rigidity of the aluminum alloy. Furthermore, since the lower limit of the Mn content is 0.01% by mass, the strength of the aluminum casting at high temperatures can be improved. Furthermore, since the lower limit of the Mn content is 0.01% by mass, the deterioration of the corrosion resistance of the aluminum casting due to Cu can be suppressed. Furthermore, since the upper limit of the Mn content is 0.75% by mass, the coarsening of the Mn-based intermetallic compound phase as a hard phase can be suppressed. Therefore, the embrittlement of the aluminum alloy can be suppressed. Therefore, the deterioration of the tensile strength of the aluminum alloy can be suppressed. Furthermore, since the upper limit of the Mn content is 0.75% by mass, the generation of sludge during the casting of the aluminum casting can be suppressed. Therefore, the occurrence of casting defects such as hard spots can be suppressed. Furthermore, since the upper limit of the Mn content is 0.75 mass %, it is possible to suppress a decrease in the electrical conductivity of the aluminum casting. The same applies to the following embodiments.

[0028] (Al: Aluminum, an unavoidable element) The balance in the aluminum alloy for casting of the first embodiment is Al and inevitable elements. In this embodiment, "unavoidable elements" means elements that are not intentionally added, but are inevitably mixed in the raw materials used or in the manufacturing process. In this embodiment and the following embodiments, the inevitable elements include elements other than those listed in each embodiment, such as Zn (zinc), Sn (tin), Pb (lead), etc. The content of the inevitable elements is preferably 7.5 mass% or less in total, more preferably 5.0 mass% or less in total, 4.0 mass% or less in total, or 3.0 mass% or less in total. The same applies to the following embodiments.

[0029] According to the aluminum alloy for casting of this embodiment, by setting the Ni content to 1.0 to 10.0 mass%, the Ni-based intermetallic compound phase can be dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, by setting the Cu content to 8.01 to 18.0 mass%, the Cu-based intermetallic compound phase can be crystallized in a network around the Ni-based intermetallic compound phase. Therefore, by allowing the Ni-based intermetallic compound phase and the Cu-based intermetallic compound phase with different crystallization regions to coexist, the rigidity of the aluminum alloy can be further improved. Furthermore, the Cu-based intermetallic compound phase forms a network around the Ni-based intermetallic compound phase, so that the tensile strength of the aluminum alloy can be improved. Furthermore, by setting the lower limit of the Mn content to 0.01 mass%, the Mn-based intermetallic compound phase can be crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, by setting the upper limit of the Mn content to 0.75 mass %, coarsening of the Mn-based intermetallic compound phase as a hard phase can be suppressed, and embrittlement of the aluminum alloy can be suppressed, thereby suppressing a decrease in the tensile strength of the aluminum alloy.

[0030] In the aluminum alloy for casting of this embodiment, the lower limit of the Ni content is preferably 1.5 mass%, more preferably 2.0 mass%, 2.1 mass%, 3.0 mass%, 3.5 mass%, or 4.0 mass%. The upper limit of the Ni content is preferably 8.0 mass%, more preferably 7.0 mass%, 6.5 mass%, or 6.1 mass%. By setting the lower and upper limits of the Ni content in this way, it is easy to improve both the rigidity and tensile strength of the aluminum alloy. Alternatively, it is easy to suppress a situation in which either the rigidity or the tensile strength is extremely reduced, and to exhibit both the rigidity and the tensile strength in a well-balanced manner. In particular, by setting the lower limit of the Ni content to 3.0 mass%, the Ni-based intermetallic compound phase can be more dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be further improved. The same applies to the following embodiments.

[0031] In the aluminum alloy for casting of this embodiment, the lower limit of the Cu content is preferably 8.2 mass%, more preferably 9.0 mass%, 9.5 mass%, 10.0 mass%, 10.1 mass%, 10.5 mass%, 11.0 mass%, 11.5 mass%, or 11.9 mass%. The upper limit of the Cu content is preferably 17.5 mass%, more preferably 17.0 mass%, 16.5 mass%, 16.0 mass%, 15.5 mass%, 15.0 mass%, or 14.7 mass%. By setting the lower and upper limits of the Cu content in this way, it is easy to improve both the rigidity and tensile strength of the aluminum alloy. Alternatively, it is easy to suppress a situation in which either the rigidity or the tensile strength is extremely reduced, and to express both the rigidity and the tensile strength in a well-balanced manner. The same applies to the following embodiments.

[0032] In the aluminum alloy for casting of this embodiment, the lower limit of the Mn content is preferably 0.05 mass%, more preferably 0.10 mass%, 0.15 mass%, 0.20 mass%, 0.25 mass%, or 0.30 mass%. The upper limit of the Mn content is preferably 0.70 mass%, more preferably 0.67 mass%, 0.65 mass%, 0.60 mass%, or 0.55 mass%. By setting the lower and upper limits of the Mn content in this way, it is easy to improve both the rigidity and tensile strength of the aluminum alloy. Alternatively, it is easy to suppress a situation in which either the rigidity or the tensile strength is extremely reduced, and to express both the rigidity and the tensile strength in a well-balanced manner. The same applies to the following embodiments.

[0033] In the casting aluminum alloy of this embodiment, the Cu content [Cu] and the Ni content [Ni] are blended so as to satisfy the following condition (1). 10.0≦[Cu]+0.87[Ni]≦23.5 (1)

[0034] In this embodiment, by satisfying condition (1), it is easy to improve both the rigidity and tensile strength of the aluminum alloy. Alternatively, it is easy to suppress a situation in which either the rigidity or the tensile strength is extremely decreased, and to exhibit both the rigidity and the tensile strength in a well-balanced manner. The lower limit of condition (1) is preferably 11.0, and more preferably 12.0 or 13.0. Moreover, the upper limit of condition (1) is preferably 23.0, and more preferably 22.5. The same applies to the following embodiments.

[0035] <Second embodiment> The casting aluminum alloy of the second embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.75 mass % Mn, 5.0 to 20.0 mass % Si, and the balance being Al and unavoidable elements.

[0036] (Si: Silicon) The casting aluminum alloy of the second embodiment contains 5.0 to 20.0 mass% of Si. In the casting aluminum alloy of this embodiment, the Si phase is dispersed and crystallized, for example, as primary crystal Si and as eutectic Si with Al. Since the lower limit of the Si content is 5.0 mass%, the crystallization amount of the Si phase can be increased. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, since the upper limit of the Si content is 20.0 mass%, the coarsening of the Si phase during the solidification process of the aluminum alloy can be suppressed. Therefore, the embrittlement of the aluminum alloy can be suppressed. Therefore, the decrease in the tensile strength of the aluminum alloy can be suppressed. Furthermore, since the upper limit of the Si content is 20.0 mass%, the increase in the buoyancy acting on the Si phase due to the coarsening of the Si phase can be suppressed. Therefore, the floating and / or separation of the Si phase in the aluminum alloy can be suppressed. Therefore, the variation in the structure and tensile strength of the aluminum alloy can be suppressed. The same applies to the following embodiments.

[0037] According to the casting aluminum alloy of this embodiment, by setting the Si content to 5.0 to 20.0 mass%, primary and eutectic Si phases can be dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, by setting the Ni content to 1.0 to 10.0 mass%, a Ni-based intermetallic compound phase can be crystallized around the Si phase. Furthermore, by setting the Cu content to 8.01 to 18.0 mass%, a Cu-based intermetallic compound phase can be crystallized in a mesh-like shape around the Si phase and the Ni-based intermetallic compound phase. Therefore, by allowing the Si phase, the Ni-based intermetallic compound phase, and the Cu-based intermetallic compound phase with different crystallization regions to coexist, the rigidity of the aluminum alloy can be further improved. Furthermore, by setting the Mn content to 0.01 to 0.75 mass%, the rigidity of the aluminum alloy can be improved and the decrease in tensile strength can be suppressed.

[0038] In the casting aluminum alloy of this embodiment, the lower limit of the Si content is preferably 5.5 mass%, more preferably 5.6 mass%, 6.0 mass%, 6.5 mass%, 7.0 mass%, 7.5 mass%, 8.0 mass%, or 8.5 mass%. The upper limit of the Si content is preferably 18.0 mass%, more preferably 17.0 mass%, 16.5 mass%, 16.4 mass%, 16.0 mass%, 15.5 mass%, 15.0 mass%, 14.5 mass%, 14.0 mass%, 13.8 mass%, or 13.5 mass%. By setting the lower and upper limits of the Si content in this way, it is easy to improve both the rigidity and tensile strength of the aluminum alloy. Alternatively, it is easy to suppress a situation in which either the rigidity or the tensile strength is extremely reduced, and to express both the rigidity and the tensile strength in a well-balanced manner. In particular, by setting the upper limit of the Si content to 14.5 mass %, it is possible to suppress the coarsening of the Si phase during the solidification process of the aluminum alloy, and to further suppress the embrittlement of the aluminum alloy, which makes it easier to improve the tensile strength of the aluminum alloy. The same applies to the following embodiments.

[0039] In the aluminum alloy for casting of this embodiment, the Si content [Si], the Cu content [Cu] and the Ni content [Ni] are blended so as to satisfy the following condition (2). 30.0≦[Si]+0.94[Cu]+2.02[Ni]≦42.5 (2)

[0040] In this embodiment, by satisfying condition (2), it is easy to improve both the rigidity and tensile strength of the aluminum alloy. Alternatively, it is easy to suppress a situation in which either the rigidity or the tensile strength is extremely decreased, and to exhibit both the rigidity and the tensile strength in a well-balanced manner. The lower limit of condition (2) is preferably 30.5, and more preferably 31.0 or 31.5. Moreover, the upper limit of condition (2) is preferably 42.0, and more preferably 41.5. The same applies to the following embodiments.

[0041] <Third embodiment> The casting aluminum alloy of the third embodiment contains 1.0 to 10.0 mass% Ni, 8.01 to 18.0 mass% Cu, 0.01 to 0.75 mass% Mn, 5.0 to 20.0 mass% Si, 0.0001 to 0.1 mass% P, and the remainder being Al and unavoidable elements.

[0042] (P: Rin) The aluminum alloy for casting according to the third embodiment contains 0.0001 to 0.1 mass% P. Since the lower limit of the P content is 0.0001 mass%, the effect of refining primary crystal Si can be improved. Therefore, primary crystal Si can be uniformly dispersed and crystallized in the aluminum alloy. Furthermore, since the upper limit of the P content is 0.1 mass%, the decrease in fluidity of the aluminum alloy can be suppressed. Therefore, the castability of the aluminum alloy can be improved. The same applies to the following embodiments.

[0043] According to the casting aluminum alloy of this embodiment, by setting the P content to 0.0001 to 0.1 mass%, AlP (aluminum phosphide) generated in the aluminum alloy acts as a heterogeneous nucleus of primary Si, so that the primary Si can be refined. Therefore, primary Si can be easily uniformly dispersed and crystallized in the aluminum alloy. Therefore, it is easy to suppress the variation in stiffness and tensile strength in the aluminum alloy.

[0044] In the casting aluminum alloy of this embodiment, the lower limit of the P content is preferably 0.0003 mass%, more preferably 0.0006 mass%. The upper limit of the P content is preferably 0.05 mass%, more preferably 0.04 mass% or 0.03 mass%. By setting the lower and upper limits of the P content in this way, it is easy to suppress the variation in the rigidity and tensile strength of the aluminum alloy. The same applies to the following embodiments.

[0045] <Fourth embodiment> The casting aluminum alloy of the fourth embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.75 mass % Mn, 0.01 to 3.0 mass % Mg, and the balance being Al and unavoidable elements.

[0046] (Mg: Magnesium) The aluminum alloy for casting according to the fourth embodiment contains 0.01 to 3.0% by mass of Mg. Since the lower limit of the Mg content is 0.01% by mass, the effect of precipitating the Mg-based intermetallic compound phase, which is an intermetallic compound phase originating from Mg, by aging the aluminum alloy can be improved. Therefore, the precipitation strengthening of the aluminum alloy can be achieved. Moreover, since the upper limit of the Mg content is 3.0% by mass, an excessive increase in the Mg-based intermetallic compound phase can be suppressed. Therefore, a decrease in the elongation of the aluminum alloy can be suppressed. The same applies to the following embodiments.

[0047] According to the casting aluminum alloy of this embodiment, by setting the Mg content to 0.01 to 3.0 mass%, it is possible to precipitate an Mg-based intermetallic compound phase, which is an intermetallic compound phase originating from Mg, by aging treatment, and therefore it is possible to further improve the tensile strength of the aluminum alloy.

[0048] In the casting aluminum alloy of this embodiment, the lower limit of the Mg content is preferably 0.05 mass%, more preferably 0.1 mass%, 0.2 mass%, or 0.3 mass%. The upper limit of the Mg content is preferably 2.5 mass%, more preferably 2.0 mass%, 1.9 mass%, 1.8 mass%, 1.5 mass%, 1.0 mass%, 0.8 mass%, or 0.6 mass%. By setting the lower and upper limits of the Mg content as described above, the tensile strength of the aluminum alloy is easily improved. The same applies to the following embodiments.

[0049] The casting aluminum alloy of this embodiment may further contain 5.0 to 20.0 mass % of Si. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.1 mass % of P.

[0050] <Fifth embodiment> The casting aluminum alloy of the fifth embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.75 mass % Mn, 0.01 to 0.80 mass % Fe, and the balance being Al and unavoidable elements.

[0051] (Fe: Iron) The aluminum alloy for casting according to the fifth embodiment contains 0.01 to 0.80% by mass of Fe. Since the lower limit of the Fe content is 0.01% by mass, an Fe-based intermetallic compound phase, which is an intermetallic compound phase resulting from Fe, can be crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, since the lower limit of the Fe content is 0.01% by mass, the occurrence of seizure of the aluminum alloy can be suppressed when the aluminum casting is cast by a die casting method. Furthermore, since the upper limit of the Fe content is 0.80% by mass, the coarsening of the Fe-based intermetallic compound phase as a hard phase can be suppressed. Therefore, the embrittlement of the aluminum alloy can be suppressed. Therefore, the decrease in the tensile strength of the aluminum alloy can be suppressed. Furthermore, since the upper limit of the Fe content is 0.80% by mass, the decrease in the corrosion resistance of the aluminum casting can be suppressed. Furthermore, since the upper limit of the Fe content is 0.80% by mass, the generation of sludge during the casting of the aluminum casting can be suppressed. Therefore, the occurrence of casting defects such as hard spots can be suppressed. The same applies to the following embodiments.

[0052] According to the casting aluminum alloy of this embodiment, by setting the Fe content to 0.01 to 0.80 mass%, the rigidity of the aluminum alloy can be improved and the decrease in tensile strength can be suppressed. Furthermore, by setting the Mn content to 0.01 to 0.75 mass%, the decrease in corrosion resistance of the aluminum casting caused by Fe can be suppressed.

[0053] In the aluminum alloy for casting of this embodiment, the lower limit of the Fe content is preferably 0.05 mass%, more preferably 0.10 mass%, 0.15 mass%, 0.20 mass%, 0.25 mass%, 0.29 mass%, 0.30 mass%, 0.31 mass%, 0.32 mass%, or 0.34 mass%. The upper limit of the Fe content is preferably 0.75 mass%, more preferably 0.70 mass%, 0.65 mass%, 0.60 mass%, or 0.55 mass%. By setting the lower and upper limits of the Fe content in this way, it is easy to improve both the rigidity and tensile strength of the aluminum alloy. Alternatively, it is easy to suppress a situation in which either the rigidity or the tensile strength is extremely reduced, and to express both the rigidity and the tensile strength in a well-balanced manner. The same applies to the following embodiments.

[0054] The casting aluminum alloy of this embodiment may further contain 5.0 to 20.0 mass% Si. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.1 mass% P. The casting aluminum alloy of this embodiment may further contain 0.01 to 3.0 mass% Mg.

[0055] Sixth embodiment The casting aluminum alloy of the sixth embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.75 mass % Mn, 0.0001 to 0.50 mass % Cr, and the balance being Al and unavoidable elements.

[0056] (Cr: Chromium) The aluminum alloy for casting according to the sixth embodiment contains 0.0001 to 0.50% by mass of Cr. Since the lower limit of the Cr content is 0.0001% by mass, the strength of the aluminum casting at high temperatures can be improved. Furthermore, since the upper limit of the Cr content is 0.50% by mass, the coarsening of the Cr-based intermetallic compound phase, which is an intermetallic compound phase caused by Cr, can be suppressed. Therefore, the embrittlement of the aluminum alloy can be suppressed. Furthermore, since the upper limit of the Cr content is 0.50% by mass, the generation of sludge during the casting of the aluminum casting can be suppressed. Therefore, the occurrence of casting defects such as hard spots can be suppressed. Furthermore, since the upper limit of the Cr content is 0.50% by mass, the decrease in the thermal conductivity and electrical conductivity of the aluminum casting can be suppressed. The same applies to the following embodiments.

[0057] In the casting aluminum alloy of this embodiment, the lower limit of the Cr content is preferably 0.001 mass%, more preferably 0.005 mass% or 0.01 mass%, and the upper limit of the Cr content is preferably 0.30 mass%, more preferably 0.10 mass%, 0.07 mass%, 0.05 mass%, or 0.03 mass%, and the same applies to the following embodiments.

[0058] The casting aluminum alloy of this embodiment may further contain 5.0 to 20.0 mass% Si. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.1 mass% P. The casting aluminum alloy of this embodiment may further contain 0.01 to 3.0 mass% Mg. The casting aluminum alloy of this embodiment may further contain 0.01 to 0.80 mass% Fe.

[0059] Seventh embodiment The casting aluminum alloy of the seventh embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.75 mass % Mn, 0.0001 to 0.75 mass % Ti, and the balance being Al and unavoidable elements.

[0060] (Ti: Titanium) The aluminum alloy for casting according to the seventh embodiment contains 0.0001 to 0.75% by mass of Ti. Since the lower limit of the Ti content is 0.0001% by mass, the crystal grains in the aluminum alloy are easily refined. Therefore, the occurrence of shrinkage cavities and hot cracks in the aluminum casting is reduced, and the heat resistance and mechanical properties are easily improved. Furthermore, since the upper limit of the Ti content is 0.75% by mass, the coarsening of the Ti-based intermetallic compound phase, which is an intermetallic compound phase caused by Ti, can be suppressed. Therefore, the deterioration of the toughness of the aluminum alloy can be suppressed. Furthermore, since the upper limit of the Ti content is 0.75% by mass, the deterioration of the electrical conductivity of the aluminum casting can be suppressed. The same applies to the following embodiments.

[0061] In the casting aluminum alloy of this embodiment, the lower limit of the Ti content is preferably 0.001 mass%, more preferably 0.005 mass%, 0.01 mass%, 0.05 mass%, or 0.10 mass%. The upper limit of the Ti content is preferably 0.50 mass%, more preferably 0.30 mass%, or 0.20 mass%. The same applies to the following embodiments.

[0062] The casting aluminum alloy of this embodiment may further contain 5.0 to 20.0 mass% Si. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.1 mass% P. The casting aluminum alloy of this embodiment may further contain 0.01 to 3.0 mass% Mg. The casting aluminum alloy of this embodiment may further contain 0.01 to 0.80 mass% Fe. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.50 mass% Cr.

[0063] <Eighth embodiment> The casting aluminum alloy of the eighth embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.75 mass % Mn, 0.0001 to 0.50 mass % V, and the balance being Al and unavoidable elements.

[0064] (V: Vanadium) The aluminum alloy for casting according to the eighth embodiment contains 0.0001 to 0.50 mass% of V. Since the lower limit of the V content is 0.0001 mass%, the heat resistance of the aluminum casting can be improved. Furthermore, since the upper limit of the V content is 0.50 mass%, the decrease in the electrical conductivity of the aluminum casting can be suppressed. The same applies to the following embodiments.

[0065] In the casting aluminum alloy of this embodiment, the lower limit of the V content is preferably 0.001 mass%, more preferably 0.005 mass% or 0.01 mass%, and the upper limit of the V content is preferably 0.30 mass%, more preferably 0.20 mass%, 0.10 mass%, or 0.07 mass%, and the same applies to the following embodiments.

[0066] The casting aluminum alloy of this embodiment may further contain 5.0 to 20.0 mass% Si. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.1 mass% P. The casting aluminum alloy of this embodiment may further contain 0.01 to 3.0 mass% Mg. The casting aluminum alloy of this embodiment may further contain 0.01 to 0.80 mass% Fe. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.50 mass% Cr. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.75 mass% Ti.

[0067] <Ninth embodiment> The casting aluminum alloy of the ninth embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.80 mass % Fe, and the balance being Al and unavoidable elements.

[0068] According to the aluminum alloy for casting of this embodiment, by setting the Ni content to 1.0 to 10.0 mass%, the Ni-based intermetallic compound phase can be dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, by setting the Cu content to 8.01 to 18.0 mass%, the Cu-based intermetallic compound phase can be crystallized in a network around the Ni-based intermetallic compound phase. Therefore, by allowing the Ni-based intermetallic compound phase and the Cu-based intermetallic compound phase with different crystallization regions to coexist, the rigidity of the aluminum alloy can be further improved. Furthermore, the Cu-based intermetallic compound phase forms a network around the Ni-based intermetallic compound phase, so that the tensile strength of the aluminum alloy can be improved. Furthermore, by setting the lower limit of the Fe content to 0.01 mass%, the Fe-based intermetallic compound phase can be crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, by setting the upper limit of the Fe content to 0.80 mass %, coarsening of the Fe-based intermetallic compound phase as a hard phase can be suppressed, and embrittlement of the aluminum alloy can be suppressed, thereby suppressing a decrease in the tensile strength of the aluminum alloy.

[0069] <Tenth embodiment> The casting aluminum alloy of the tenth embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.80 mass % Fe, 5.0 to 20.0 mass % Si, and the remainder being Al and unavoidable elements.

[0070] According to the casting aluminum alloy of this embodiment, by setting the Si content to 5.0 to 20.0 mass%, primary and eutectic Si phases can be dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Furthermore, by setting the Ni content to 1.0 to 10.0 mass%, a Ni-based intermetallic compound phase can be crystallized around the Si phase. Furthermore, by setting the Cu content to 8.01 to 18.0 mass%, a Cu-based intermetallic compound phase can be crystallized in a mesh-like shape around the Si phase and the Ni-based intermetallic compound phase. Therefore, by allowing the Si phase, the Ni-based intermetallic compound phase, and the Cu-based intermetallic compound phase with different crystallization regions to coexist, the rigidity of the aluminum alloy can be further improved. Furthermore, by setting the Fe content to 0.01 to 0.80 mass%, the rigidity of the aluminum alloy can be improved and the decrease in tensile strength can be suppressed.

[0071] <Eleventh embodiment> The casting aluminum alloy of the eleventh embodiment contains 1.0 to 10.0 mass% Ni, 8.01 to 18.0 mass% Cu, 0.01 to 0.80 mass% Fe, 5.0 to 20.0 mass% Si, 0.0001 to 0.1 mass% P, and the remainder being Al and unavoidable elements.

[0072] According to the casting aluminum alloy of this embodiment, by setting the P content to 0.0001 to 0.1 mass%, AlP (aluminum phosphide) generated in the aluminum alloy acts as a heterogeneous nucleus of primary Si, so that the primary Si can be refined. Therefore, primary Si can be easily uniformly dispersed and crystallized in the aluminum alloy. Therefore, it is easy to suppress the variation in stiffness and tensile strength in the aluminum alloy.

[0073] <Twelfth embodiment> The casting aluminum alloy of the twelfth embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.80 mass % Fe, 0.01 to 3.0 mass % Mg, and the balance being Al and unavoidable elements.

[0074] According to the casting aluminum alloy of this embodiment, by setting the Mg content to 0.01 to 3.0 mass%, it is possible to precipitate an Mg-based intermetallic compound phase, which is an intermetallic compound phase originating from Mg, by aging treatment, and therefore it is possible to further improve the tensile strength of the aluminum alloy.

[0075] The casting aluminum alloy of this embodiment may further contain 5.0 to 20.0 mass % of Si. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.1 mass % of P.

[0076] <Thirteenth embodiment> The casting aluminum alloy of the thirteenth embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.80 mass % Fe, 0.0001 to 0.50 mass % Cr, and the balance being Al and unavoidable elements.

[0077] The casting aluminum alloy of this embodiment may further contain 5.0 to 20.0 mass% Si. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.1 mass% P. The casting aluminum alloy of this embodiment may further contain 0.01 to 3.0 mass% Mg. The casting aluminum alloy of this embodiment may further contain 0.01 to 0.75 mass% Mn.

[0078] <Fourteenth embodiment> The casting aluminum alloy of the fourteenth embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.80 mass % Fe, 0.0001 to 0.75 mass % Ti, and the balance being Al and unavoidable elements.

[0079] The casting aluminum alloy of this embodiment may further contain 5.0 to 20.0 mass% Si. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.1 mass% P. The casting aluminum alloy of this embodiment may further contain 0.01 to 3.0 mass% Mg. The casting aluminum alloy of this embodiment may further contain 0.01 to 0.75 mass% Mn. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.50 mass% Cr.

[0080] <Fifteenth embodiment> The casting aluminum alloy of the fifteenth embodiment contains 1.0 to 10.0 mass % Ni, 8.01 to 18.0 mass % Cu, 0.01 to 0.80 mass % Fe, 0.0001 to 0.50 mass % V, and the balance being Al and unavoidable elements.

[0081] The casting aluminum alloy of this embodiment may further contain 5.0 to 20.0 mass% Si. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.1 mass% P. The casting aluminum alloy of this embodiment may further contain 0.01 to 3.0 mass% Mg. The casting aluminum alloy of this embodiment may further contain 0.01 to 0.75 mass% Mn. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.50 mass% Cr. The casting aluminum alloy of this embodiment may further contain 0.0001 to 0.75 mass% Ti.

[0082] By using the aluminum alloy for casting according to the above embodiment, it is possible to provide an aluminum casting having high rigidity and excellent tensile strength. Therefore, this aluminum casting is suitable for a wide variety of applications requiring high rigidity and high tensile strength. Examples of applications of this aluminum casting include components for machine tools, robots, automobiles, etc.

[0083] <Example> FIG. 1 shows the composition (mass%), the value of condition (1), the value of condition (2), Young's modulus (GPa), and tensile strength (MPa) of some examples and comparative examples of the casting aluminum alloy according to the above embodiment. In FIG. 1, the content (mass%) of each element is a value measured by inductively coupled plasma optical emission spectrometry using an ICP (inductively coupled plasma optical emission) analyzer "iCAP 7400 ICP-OES" manufactured by Thermo Fisher Scientific Co., Ltd. In addition, the tensile strength (MPa) is a value measured according to "JIS Z 2241 (Metallic Material Tensile Test Method)" for the test pieces of the casting aluminum alloy according to the examples and comparative examples. The test pieces used were No. 14A test pieces with a diameter of 6 mm and a parallel length of 36 mm cast by the mold casting method. In addition, the Young's modulus is a value obtained from the slope within the elastic range of the relationship between stress and strain in a tensile test. The strain was taken as the average value of the measured values ​​of two uniaxial strain gauges attached opposite to each other on the parallel part surface of the test piece.

[0084] (Comparison of Examples 1 to 10 with Comparative Example 1) As shown in FIG. 1, the Cu content in Examples 1 to 10 is 8.01 mass% or more, while the Cu content in Comparative Example 1 is less than 8.01 mass%. In addition, the Fe content in Examples 1 to 10 is 0.80 mass% or less, while the Fe content in Comparative Example 1 exceeds 0.80 mass%. Here, the Young's modulus in Examples 1 to 10 is 95 to 108 GPa, while the Young's modulus in Comparative Example 1 is 95 GPa. Therefore, in Examples 1 to 10, the rigidity is improved by about 14% at maximum compared to Comparative Example 1. In addition, the tensile strength in Examples 1 to 10 is 170 to 261 MPa, while the tensile strength in Comparative Example 1 is 160 MPa. Therefore, in Examples 1 to 10, the tensile strength is improved by about 63% at maximum (about 6% at minimum) compared to Comparative Example 1. In this way, it was confirmed that the rigidity and tensile strength of the casting aluminum alloy can be improved by setting the lower limit of the Cu content to 8.01 mass% and the upper limit of the Fe content to 0.80 mass%.

[0085] (Comparison of Examples 1 to 10 with Comparative Example 2) As shown in FIG. 1, the Cu content of Examples 1 to 10 is 18.0 mass% or less, whereas the Cu content of Comparative Example 2 exceeds 18.0 mass%. Here, the Young's modulus of Examples 1 to 10 is 95 to 108 GPa, whereas the Young's modulus of Comparative Example 2 is 104 GPa. Therefore, in Examples 1 to 10, the fluctuation width of the rigidity is within a range of 4 to 9% compared to Comparative Example 2. In addition, the tensile strength of Examples 1 to 10 is 170 to 261 MPa, whereas the tensile strength of Comparative Example 2 is 119 MPa. Therefore, in Examples 1 to 10, the tensile strength is improved by a maximum of about 120% (at least about 43%) compared to Comparative Example 2. In this way, it was confirmed that by setting the upper limit of the Cu content to 18.0 mass%, it is possible to suppress the variation in rigidity of the aluminum alloy for casting, stably express the rigidity, and remarkably improve the tensile strength.

[0086] (Comparison of Examples 1 to 10 with Comparative Example 3) As shown in FIG. 1, the Mn content of Examples 1 to 10 is 0.75 mass% or less, whereas the Mn content of Comparative Example 3 exceeds 0.75 mass%. Here, the Young's modulus of Examples 1 to 10 is 95 to 108 GPa, whereas the Young's modulus of Comparative Example 3 is 105 GPa. Therefore, in Examples 1 to 10, the fluctuation width of the rigidity is within a range of 3 to 10% compared to Comparative Example 3. In addition, the tensile strength of Examples 1 to 10 is 170 to 261 MPa, whereas the tensile strength of Comparative Example 3 is 153 MPa. Therefore, in Examples 1 to 10, the tensile strength is improved by a maximum of about 71% (at least about 11%) compared to Comparative Example 3. In this way, it was confirmed that by setting the upper limit of the Mn content to 0.75 mass%, it is possible to suppress the variation in rigidity of the aluminum alloy for casting, stably express rigidity, and remarkably improve the tensile strength.

[0087] (Comparison of Examples 2 to 9 with Example 1) As shown in FIG. 1, the Cu content of Examples 2 to 9 is 9.0 mass% or more, whereas the Cu content of Example 1 is less than 9.0 mass%. Here, the Young's modulus of Examples 2 to 9 is 95 to 108 GPa, whereas the Young's modulus of Example 1 is 99 GPa. Therefore, in Examples 2 to 9, the fluctuation width of the rigidity is within a range of 4 to 9% compared to Example 1. In addition, the tensile strength of Examples 2 to 9 is 181 to 261 MPa, whereas the tensile strength of Example 1 is 172 MPa. Therefore, in Examples 2 to 9, the tensile strength is improved by a maximum of about 52% (at least about 5%) compared to Example 1. In this way, it was confirmed that by setting the lower limit of the Cu content to 9.0 mass%, it is possible to suppress the variation in rigidity of the aluminum alloy for casting, stably express the rigidity, and improve the tensile strength.

[0088] (Comparison of Examples 2 to 9 with Example 10) As shown in FIG. 1, the Cu content of Examples 2 to 9 is 15.5 mass% or less, whereas the Cu content of Example 10 exceeds 15.5 mass%. Here, the Young's modulus of Examples 2 to 9 is 95 to 108 GPa, whereas the Young's modulus of Example 10 is 104 GPa. Therefore, in Examples 2 to 9, the fluctuation width of the rigidity is within a range of 4 to 9% compared to Example 10. In addition, the tensile strength of Examples 2 to 9 is 181 to 261 MPa, whereas the tensile strength of Example 10 is 170 MPa. Therefore, in Examples 2 to 9, the tensile strength is improved by a maximum of about 54% (at least about 6%) compared to Example 10. In this way, it was confirmed that by setting the upper limit of the Cu content to 15.5 mass%, it is possible to suppress the variation in rigidity of the aluminum alloy for casting, stably express the rigidity, and improve the tensile strength.

[0089] (Structure of aluminum alloys for casting) Observation results of the structures of test pieces of the aluminum alloys for casting are shown in Fig. 2 to Fig. 8. Fig. 2 shows the results of observation of the microstructures of Comparative Example 1, Fig. 3 shows Example 1, Fig. 4 shows Example 2, Fig. 5 shows Example 3, Fig. 6 shows Example 8, Fig. 7 shows Example 10, and Fig. 8 shows Comparative Example 2, observed by a scanning electron microscope (SEM).

[0090] As shown in FIG. 1, the Cu content of Comparative Example 1 is 4.74 mass%. As shown in FIG. 2, in Comparative Example 1, thin needle-like Cu-based intermetallic compound phases 30 are sparsely crystallized around the Si phase 10 and the Ni-based intermetallic compound phase 20 crystallized in the aluminum alloy. In Comparative Example 1, there are many parts in the aluminum alloy where the Cu-based intermetallic compound phase 30 is not crystallized, and even in parts where the Cu-based intermetallic compound phase 30 is crystallized, the adjacent Cu-based intermetallic compound phases 30 are discontinuously distributed with each other being disconnected. As a result, as shown in FIG. 1, it is difficult to improve the tensile strength of the aluminum alloy for casting in Comparative Example 1.

[0091] As shown in FIG. 1, the Cu content is 8.20 mass% in Example 1, 10.12 mass% in Example 2, 11.88 mass% in Example 3, 15.02 mass% in Example 8, and 16.98 mass% in Example 10. As shown in FIG. 3 to FIG. 7, in Examples 1, 2, 3, 8, and 10, the Cu-based intermetallic compound phase 30 is crystallized almost uniformly over almost the entire area of ​​the aluminum alloy. In Examples 1, 2, 3, 8, and 10, the adjacent Cu-based intermetallic compound phases 30 are continuously distributed in a state of being connected to each other, and a mesh-like network is formed between some of the Cu-based intermetallic compound phases 30. As a result, as shown in FIG. 1, in Examples 1, 2, 3, 8, and 10, the tensile strength of the aluminum alloy for casting can be improved. 4 to 6, the Cu-based intermetallic compound phase 30 itself constituting the mesh grows thicker, and the mesh-like network expands to be distributed over almost the entire area of ​​the aluminum alloy in Examples 2, 3 and 8. As a result, as shown in FIG. 1, the tensile strength of the aluminum alloy for casting in Examples 2, 3 and 8 can be further improved.

[0092] As shown in Fig. 1, the Cu content in Comparative Example 2 is 18.5 mass%. As shown in Fig. 8, in Comparative Example 2, the Cu-based intermetallic compound phase 30 itself constituting the network is coarsened into granular (lumpy) form, and the network is broken and / or destroyed. As a result, as shown in Fig. 1, it is difficult to improve the tensile strength of the aluminum alloy for casting in Comparative Example 2.

[0093] As a result of observing the structure of the test piece of the casting aluminum alloy, it was confirmed that the Si phase 10, the Ni-based intermetallic compound phase 20, and the Cu-based intermetallic compound phase 30, which have different crystallization regions, can coexist. In addition, it was confirmed that the Cu-based intermetallic compound phase 30 can be continuously crystallized in a mesh-like manner around the Si phase 10 and the Ni-based intermetallic compound phase 20 by setting the Cu content to 8.01 to 18.0 mass %. In addition, it was confirmed that the Cu-based intermetallic compound phase 30 can form a mesh-like network over almost the entire area of ​​the aluminum alloy by setting the Cu content to 9.0 to 15.5 mass %. As a result, as shown in FIG. 1, in Examples 1 to 10, the rigidity of the casting aluminum alloy can be improved, or the rigidity can be stably expressed with a small fluctuation range, as well as the tensile strength can be improved, compared to Comparative Examples 1 and 2.

[0094] Each of the compositions in the above embodiments (first to fifteenth embodiments) can also be applied to aluminum alloy powder for additive manufacturing. Aluminum alloy powder for additive manufacturing can be manufactured by various powder manufacturing methods such as water atomization, gas atomization, disk atomization, and plasma atomization. Since this composition is an aluminum alloy composition, for example, disk atomization, which is suitable for powdering low melting point materials, can be used to powder the alloy of this composition.

[0095] By using the aluminum alloy powder for additive manufacturing to which each of the compositions in the above embodiments (first embodiment to fifteenth embodiment) is applied, an additively manufactured product having high rigidity and excellent tensile strength can be provided. Therefore, this additively manufactured product is suitable for a wide variety of applications requiring high rigidity and high tensile strength. Examples of applications of this additively manufactured product include aerospace equipment, transportation equipment, medical equipment, and components thereof, in addition to the above-mentioned examples of applications of aluminum castings. The additively manufactured product can be manufactured by various three-dimensional additive manufacturing methods such as a powder bed method, a deposition method, and a binder jetting method using, for example, a metal 3D printer. [Explanation of symbols]

[0096] 10 Si phase 20 Ni-based intermetallic compound phase 30 Cu-based intermetallic compound phase

Claims

1. 1.0 to 10.0 mass% Ni, 8.01 to 18.0 mass% Cu, 0.01 to 0.75 mass% Mn, 0.01 to 0.80 mass% Fe, 5.0 to 20.0 mass% Si, 0.01 to 3.0 mass% Mg, 0.0001 to 0.50 mass% Cr, 0.0001 to 0.75 mass% Ti, 0.0001 to 0.50 mass% V, with the balance being Al and unavoidable elements, A casting aluminum alloy, in which the Si content [Si], the Cu content [Cu], and the Ni content [Ni] satisfy the following condition (2): 30.0≦[Si]+0.94[Cu]+2.02[Ni]≦42.5...(2)

2. 2. The casting aluminum alloy according to claim 1, wherein the Ni content is 3.0 to 10.0 mass %.

3. 2. The casting aluminum alloy according to claim 1, wherein the Cu content [Cu] and the Ni content [Ni] satisfy the following condition (1): 10.0≦[Cu]+0.87[Ni]≦23.5...(1)

4. 2. The casting aluminum alloy according to claim 1, wherein the Si content is 5.0 to 14.5 mass%.

5. 2. The casting aluminum alloy according to claim 1, further comprising 0.0001 to 0.1 mass % P.

6. 2. The casting aluminum alloy according to claim 1, wherein the Cu content is 9.0 to 15.5 mass%.

7. An aluminum casting cast using the aluminum alloy for casting according to any one of claims 1 to 6.

8. 1.0 to 10.0 mass% Ni, 8.01 to 18.0 mass% Cu, 0.01 to 0.75 mass% Mn, 0.01 to 0.80 mass% Fe, 5.0 to 20.0 mass% Si, 0.01 to 3.0 mass% Mg, 0.0001 to 0.50 mass% Cr, 0.0001 to 0.75 mass% Ti, 0.0001 to 0.50 mass% V, with the balance being Al and unavoidable elements, An aluminum alloy powder for additive manufacturing, wherein the Si content [Si], the Cu content [Cu], and the Ni content [Ni] satisfy the following condition (2). 30.0≦[Si]+0.94[Cu]+2.02[Ni]≦42.5...(2)

9. The aluminum alloy powder for additive manufacturing as described in claim 8, wherein the Ni content is 3.0 to 10.0 mass%.

10. An aluminum alloy powder for additive manufacturing as described in claim 8, wherein the Cu content [Cu] and the Ni content [Ni] satisfy the following condition (1). 10.0≦[Cu]+0.87[Ni]≦23.5...(1)

11. The aluminum alloy powder for additive manufacturing as described in claim 8, wherein the Si content is 5.0 to 14.5 mass%.

12. The aluminum alloy powder for additive manufacturing according to claim 8, further containing 0.0001 to 0.1 mass% P.

13. The aluminum alloy powder for additive manufacturing as described in claim 8, wherein the Cu content is 9.0 to 15.5 mass%.

14. A laminated object produced by laminate manufacturing using the aluminum alloy powder for laminate manufacturing according to any one of claims 8 to 13.

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