Aluminum alloy for casting and aluminum casting made by casting the same

Abstract

To provide an aluminum alloy for casting having high rigidity and superior tensile strength.SOLUTION: An aluminum alloy for casting includes 2.1 to 10.0 mass% of Ni, 10.1 to 18.0 mass% of Cu, 0.01 to 0.75 mass% of Mn, 0.01 to 0.80 mass% of Fe, 5.0 to 20.0 mass% of Si, 0.01 to 3.0 mass% of Mg, 0.0001 to 0.50 mass% of Cr, 0.0001 to 0.75 mass% of Ti, and 0.0001 to 0.50 mass% of V, with the balance being Al and inevitable elements.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] Patent Document 1 (International Publication No. 2015 / 152133) discloses an Al-Si-Mg-based aluminum alloy for casting, which consists of 12.0 to 14.0% Si, 1.5 to 4.0% Mg, 0.10% or less Mn, and the balance being Al and inevitable impurities by mass, and having excellent specific rigidity, strength, and ductility, and a casting member made thereof.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a demand for an aluminum alloy for casting that has high rigidity and excellent tensile strength.

Means for Solving the Problems

[0005] One aspect of the present invention is an aluminum alloy for casting, which contains 2.1 to 10.0% by mass of Ni, 10.1 to 18.0% by mass of Cu, 0.01 to 0.75% by mass of Mn, 0.01 to 0.80% by mass of Fe, 5.0 to 20.0% by mass of Si, 0.01 to 3.0% by mass of Mg, 0.0001 to 0.50% by mass of Cr, 0.0001 to 0.75% by mass of Ti, 0.0001 to 0.50% by mass of V, and the balance being Al and inevitable elements.

[0006] Another aspect of the present invention is an aluminum casting cast using the above aluminum alloy for casting.

[0007] Another aspect of the present invention is an aluminum alloy powder for additive manufacturing, comprising 2.1 to 10.0% by mass of Ni, 10.1 to 18.0% by mass of Cu, 0.01 to 0.75% by mass of Mn, 0.01 to 0.80% by mass of Fe, 5.0 to 20.0% by mass of Si, 0.01 to 3.0% by mass of Mg, 0.0001 to 0.50% by mass of Cr, 0.0001 to 0.75% by mass of Ti, 0.0001 to 0.50% by mass of V, with the balance being Al and inevitable elements.

[0008] Another aspect of the present invention is an additive manufactured object formed by additive manufacturing using the above aluminum alloy powder for additive manufacturing.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0010] Hereinafter, with reference to the accompanying drawings, several embodiments to which the composition of the aluminum alloy (content of constituent elements) (hereinafter referred to as "this composition") disclosed in the present application is applicable will be described. An example of an embodiment to which this composition is applicable is an aluminum alloy composition having this composition (hereinafter referred to as "aluminum alloy composition"). Another example of an embodiment to which this composition is applicable is an article manufactured using the aluminum alloy composition (hereinafter referred to as "this article").

[0011] Examples of embodiments of the aluminum alloy composition include, for example, aluminum alloys for casting, aluminum alloy powders for additive manufacturing, materials for welding, materials for thermal spraying, and the like. Examples of embodiments of this article include, for example, aluminum castings cast using an aluminum alloy for casting, additive manufactured objects additive manufactured using an aluminum alloy powder for additive manufacturing, shaped objects shaped using a material for welding, shaped objects shaped using a material for thermal spraying, and the like. Hereinafter, a plurality of embodiments (the first embodiment to the fifteenth embodiment) of the aluminum alloy for casting will be described, but the compositions in these plurality of embodiments can also be applied to aluminum alloy powders for additive manufacturing, materials for welding, materials for thermal spraying, and the like. Note that the present invention is not limited to the following embodiments (the first embodiment to the fifteenth embodiment).

[0012] <The First Embodiment> The aluminum alloy for casting according to the first embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, and 0.01 to 0.75% by mass of Mn, and the balance is Al and unavoidable elements.

[0013] In the present embodiment, "casting" includes casting by various casting methods such as sand casting, die casting, and die-casting methods. Further, "aluminum alloy" means an alloy containing an aluminum phase as a main phase. Therefore, "aluminum alloy for casting" means an aluminum alloy cast by various casting methods such as sand casting, die casting, and die-casting methods. "Mass%" of an element means the percentage of the mass of the element with respect to the mass of the aluminum alloy for casting. For example, the notation "element of A to B mass%" means that the mass% of the element is A% or more and B% or less. "Balance" means components other than the listed elements among the components constituting the aluminum alloy for casting. For example, the notation "an aluminum alloy for casting containing... Ni,... Cu,... Mn, with the balance being Al and inevitable elements." means that among the components constituting the aluminum alloy for casting, the components other than Ni, Cu, and Mn are Al and inevitable elements. The same applies to the following embodiments.

[0014] (Ni: Nickel) The aluminum alloy for casting of the first embodiment contains 1.0 to 10.0 mass% of Ni. In the aluminum alloy for casting of the present embodiment, an Ni-based intermetallic compound phase, which is a long flaky intermetallic compound phase caused by Ni, precipitates and disperses as, for example, primary crystals in the aluminum alloy. Since the lower limit of the Ni content is 1.0 mass%, the amount of the Ni-based intermetallic compound phase formed can be increased. Therefore, the rigidity of the aluminum alloy can be improved. Further, since the upper limit of the Ni content is 10.0 mass%, coarsening of the Ni-based intermetallic compound phase during the solidification process of the aluminum alloy can be suppressed. Therefore, for example, it is easy to prevent a situation where cracks progress along the long-side-shaped Ni-based intermetallic compound phase. Therefore, a decrease in the tensile strength of the aluminum alloy can be suppressed. The same applies to the following embodiments.

[0015] (Cu: Copper) The aluminum alloy for casting according to the first embodiment contains 8.01 to 18.0 mass% of Cu. In the aluminum alloy for casting of the present embodiment, a Cu-based intermetallic compound phase, which is an intermetallic compound phase caused by Cu, crystallizes in a network form, for example, as a eutectic with Al, around the Ni-based intermetallic compound phase. Since the lower limit of the Cu content is 8.01 mass%, the amount of the Cu-based intermetallic compound phase formed can be increased. Therefore, the rigidity of the aluminum alloy can be improved. Further, 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, embrittlement of the aluminum alloy can be suppressed. Accordingly, a decrease in the tensile strength of the aluminum alloy can be suppressed. The same applies to the following embodiments.

[0016] (Mn: Manganese) The aluminum alloy for casting according to the first embodiment contains 0.01 to 0.75 mass% of Mn. Since the lower limit of the Mn content is 0.01 mass%, an Mn-based intermetallic compound phase, which is an intermetallic compound phase caused by Mn, can be crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Further, since the lower limit of the Mn content is 0.01 mass%, the strength of the aluminum casting at high temperatures can be improved. Further, since the lower limit of the Mn content is 0.01 mass%, a decrease in the corrosion resistance of the aluminum casting due to Cu can be suppressed. Also, since the upper limit of the Mn content is 0.75 mass%, coarsening of the Mn-based intermetallic compound phase as a hard phase can be suppressed. Therefore, embrittlement of the aluminum alloy can be suppressed. Accordingly, a decrease in the tensile strength of the aluminum alloy can be suppressed. Further, since the upper limit of the Mn content is 0.75 mass%, generation of sludge during casting of the aluminum casting can be suppressed. Therefore, the occurrence of casting defects such as hard spots can be suppressed. Further, since the upper limit of the Mn content is 0.75 mass%, a decrease in the electrical conductivity of the aluminum casting can be suppressed. The same applies to the following embodiments.

[0017] (Aluminum, inevitable element) The balance in the aluminum alloy for casting of the first embodiment consists of Al and inevitable elements. In this embodiment, "inevitable elements" means elements that are not intentionally added but are inevitably mixed in during raw material use, manufacturing processes, etc. In this embodiment and the following embodiments, inevitable elements include elements other than those listed in each embodiment, for example, elements such as Zn (zinc), Sn (tin), Pb (lead), etc. The total content of inevitable elements is preferably 7.5 mass% or less, 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.

[0018] According to the aluminum alloy for casting of this embodiment, by setting the Ni content to 1.0 to 10.0 mass%, Ni-based intermetallic compound phases 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%, Cu-based intermetallic compound phases can be crystallized in a network around the Ni-based intermetallic compound phases. Therefore, by coexisting Ni-based intermetallic compound phases and Cu-based intermetallic compound phases with different crystallization regions, the rigidity of the aluminum alloy can be further improved. Also, the Cu-based intermetallic compound phases form a network around the Ni-based intermetallic compound phases, thereby improving the tensile strength of the aluminum alloy. Furthermore, by setting the lower limit of the Mn content to 0.01 mass%, Mn-based intermetallic compound phases can be crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Also, by setting the upper limit of the Mn content to 0.75 mass%, coarsening of the Mn-based intermetallic compound phases as hard phases can be suppressed, and embrittlement of the aluminum alloy can be suppressed. Therefore, a decrease in the tensile strength of the aluminum alloy can be suppressed.

[0019] In the aluminum alloy for casting of the present embodiment, the lower limit of the Ni content is preferably 1.5% by mass, more preferably 2.0% by mass, 2.1% by mass, 3.0% by mass, 3.5% by mass or 4.0% by mass. Further, the upper limit of the Ni content is preferably 8.0% by mass, more preferably 7.0% by mass, 6.5% by mass or 6.1% by mass. By setting the lower limit and the upper limit of the Ni content in this way, it is easy to improve both the rigidity and the tensile strength of the aluminum alloy. Alternatively, it is possible to suppress a situation in which either the rigidity or the tensile strength extremely decreases, and it is easy to balance the expression of both the rigidity and the tensile strength. In particular, by setting the lower limit of the Ni content to 3.0% by mass, the Ni-based intermetallic compound phase can be more dispersed and crystallized in the aluminum alloy. For this reason, the rigidity of the aluminum alloy can be further improved. The same applies to the following embodiments.

[0020] In the aluminum alloy for casting of the present embodiment, the lower limit of the Cu content is preferably 8.2% by mass, more preferably 9.0% by mass, 9.5% by mass, 10.0% by mass, 10.1% by mass, 10.5% by mass, 11.0% by mass, 11.5% by mass or 11.9% by mass. Further, the upper limit of the Cu content is preferably 17.5% by mass, more preferably 17.0% by mass, 16.5% by mass, 16.0% by mass, 15.5% by mass, 15.0% by mass or 14.7% by mass. By setting the lower limit and the upper limit of the Cu content in this way, it is easy to improve both the rigidity and the tensile strength of the aluminum alloy. Alternatively, it is possible to suppress a situation in which either the rigidity or the tensile strength extremely decreases, and it is easy to balance the expression of both the rigidity and the tensile strength. The same applies to the following embodiments.

[0021] In the aluminum alloy for casting of the present embodiment, the lower limit of the Mn content is preferably 0.05% by mass, more preferably 0.10% by mass, 0.15% by mass, 0.20% by mass, 0.25% by mass or 0.30% by mass. Also, the upper limit of the Mn content is preferably 0.70% by mass, more preferably 0.67% by mass, 0.65% by mass, 0.60% by mass or 0.55% by mass. By setting the lower limit and the upper limit of the Mn content in this way, it is easy to improve both the rigidity and the tensile strength of the aluminum alloy. Alternatively, it is possible to suppress a situation in which either the rigidity or the tensile strength extremely decreases, and it is easy to balance the expression of both the rigidity and the tensile strength. The same applies to the following embodiments.

[0022] In the aluminum alloy for casting of the present 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)

[0023] In the present embodiment, by satisfying the condition (1), it is easy to improve both the rigidity and the tensile strength of the aluminum alloy. Alternatively, it is possible to suppress a situation in which either the rigidity or the tensile strength extremely decreases, and it is easy to balance the expression of both the rigidity and the tensile strength. The lower limit of the condition (1) is preferably 11.0, more preferably 12.0 or 13.0. Also, the upper limit of the condition (1) is preferably 23.0, more preferably 22.5. The same applies to the following embodiments.

[0024] <Second Embodiment> The aluminum alloy for casting of the second embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.75% by mass of Mn, 5.0 to 20.0% by mass of Si, and the balance is Al and inevitable elements.

[0025] (Si: Silicon) The aluminum alloy for casting of the second embodiment contains 5.0 to 20.0 mass% of Si. In the aluminum alloy for casting of this embodiment, the Si phase crystallizes and disperses, for example, as primary Si and eutectic Si with Al, respectively. Since the lower limit of the Si content is 5.0 mass%, the amount of crystallized Si phase can be increased. Therefore, the rigidity of the aluminum alloy can be improved. Also, since the upper limit of the Si content is 20.0 mass%, coarsening of the Si phase during the solidification process of the aluminum alloy can be suppressed. Therefore, embrittlement of the aluminum alloy can be suppressed. Accordingly, a decrease in the tensile strength of the aluminum alloy can be suppressed. Further, since the upper limit of the Si content is 20.0 mass%, an increase in the buoyancy acting on the Si phase due to coarsening of the Si phase can be suppressed. Therefore, floating and / or separation of the Si phase in the aluminum alloy can be suppressed. Accordingly, variations in the structure and tensile strength of the aluminum alloy can be suppressed. The same applies to the following embodiments.

[0026] According to the aluminum alloy for casting of this embodiment, by setting the Si content to 5.0 to 20.0 mass%, primary and eutectic Si phases can be crystallized and dispersed in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Further, by setting the Ni content to 1.0 to 10.0 mass%, an Ni-based intermetallic compound phase can be crystallized around the Si phase. Further, by setting the Cu content to 8.01 to 18.0 mass%, a Cu-based intermetallic compound phase can be crystallized in a network around the Si phase and the Ni-based intermetallic compound phase. Therefore, by coexisting the Si phase, Ni-based intermetallic compound phase, and Cu-based intermetallic compound phase with different crystallization regions, the rigidity of the aluminum alloy can be further improved. Further, by setting the Mn content to 0.01 to 0.75 mass%, the rigidity of the aluminum alloy can be improved and a decrease in the tensile strength can be suppressed.

[0027] In the aluminum alloy for casting of the present embodiment, the lower limit of the Si content is preferably 5.5% by mass, more preferably 5.6% by mass, 6.0% by mass, 6.5% by mass, 7.0% by mass, 7.5% by mass, 8.0% by mass, or 8.5% by mass. Further, the upper limit of the Si content is preferably 18.0% by mass, more preferably 17.0% by mass, 16.5% by mass, 16.4% by mass, 16.0% by mass, 15.5% by mass, 15.0% by mass, 14.5% by mass, 14.0% by mass, 13.8% by mass, or 13.5% by mass. By setting the lower limit and the upper limit of the Si content in this way, it is easy to improve both the rigidity and the tensile strength of the aluminum alloy. Alternatively, it is possible to suppress a situation in which either the rigidity or the tensile strength extremely decreases, and it is easy to balance the expression of both the rigidity and the tensile strength. In particular, by setting the upper limit of the Si content to 14.5% by mass, it is possible to suppress the coarsening of the Si phase during the solidification process of the aluminum alloy, and it is easier to further suppress the embrittlement of the aluminum alloy. For this reason, it is easy to improve the tensile strength of the aluminum alloy. The same applies to the following embodiments.

[0028] In the aluminum alloy for casting of the present 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)

[0029] In the present embodiment, by satisfying condition (2), it is easy to improve both the rigidity and the tensile strength of the aluminum alloy. Alternatively, it is possible to suppress a situation in which either the rigidity or the tensile strength extremely decreases, and it is easy to balance the expression of both the rigidity and the tensile strength. The lower limit of condition (2) is preferably 30.5, more preferably 31.0 or 31.5. Further, the upper limit of condition (2) is preferably 42.0, more preferably 41.5. The same applies to the following embodiments.

[0030] <Third Embodiment> The aluminum alloy for casting according to the third embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.75% by mass of Mn, 5.0 to 20.0% by mass of Si, and 0.0001 to 0.1% by mass of P, with the balance being Al and inevitable elements.

[0031] (P: Phosphorus) The aluminum alloy for casting according to the third embodiment contains 0.0001 to 0.1% by mass of P. Since the lower limit of the P content is 0.0001% by mass, the effect of refining primary Si can be improved. Therefore, primary Si can be uniformly dispersed and crystallized in the aluminum alloy. Also, since the upper limit of the P content is 0.1% by mass, a decrease in the fluidity of the aluminum alloy can be suppressed. Thus, the castability of the aluminum alloy can be improved. The same applies to the following embodiments.

[0032] According to the aluminum alloy for casting of the present embodiment, by setting the P content to 0.0001 to 0.1% by mass, AlP (aluminum phosphide) generated in the aluminum alloy acts as a heterogeneous nucleus for primary Si, so that primary Si can be refined. Therefore, it is easy to uniformly disperse and crystallize primary Si in the aluminum alloy. Thus, it is easy to suppress variations in rigidity and tensile strength in the aluminum alloy.

[0033] In the aluminum alloy for casting of the present embodiment, the lower limit of the P content is preferably 0.0003% by mass, and more preferably 0.0006% by mass. Also, the upper limit of the P content is preferably 0.05% by mass, and more preferably 0.04% by mass or 0.03% by mass. By setting the lower limit and upper limit of the P content in this way, it is easy to suppress variations in rigidity and tensile strength of the aluminum alloy. The same applies to the following embodiments.

[0034] <Fourth Embodiment> The aluminum alloy for casting according to the fourth embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.75% by mass of Mn, and 0.01 to 3.0% by mass of Mg, with the balance being Al and inevitable elements.

[0035] (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 caused by Mg, by the aging treatment of the aluminum alloy can be improved. Therefore, precipitation strengthening of the aluminum alloy can be achieved. Also, 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.

[0036] According to the aluminum alloy for casting of the present embodiment, by setting the Mg content to 0.01 to 3.0% by mass, the Mg-based intermetallic compound phase, which is an intermetallic compound phase caused by Mg, can be precipitated by the aging treatment. Therefore, the tensile strength of the aluminum alloy can be further improved.

[0037] In the aluminum alloy for casting of the present embodiment, the lower limit of the Mg content is preferably 0.05% by mass, and more preferably 0.1% by mass, 0.2% by mass, or 0.3% by mass. Also, the upper limit of the Mg content is preferably 2.5% by mass, and more preferably 2.0% by mass, 1.9% by mass, 1.8% by mass, 1.5% by mass, 1.0% by mass, 0.8% by mass, or 0.6% by mass. By setting the lower limit and the upper limit of the Mg content in this way, it is easy to improve the tensile strength of the aluminum alloy. The same applies to the following embodiments.

[0038] The aluminum alloy for casting according to this embodiment may further contain 5.0 to 20.0% by mass of Si. Further, the aluminum alloy for casting according to this embodiment may further contain 0.0001 to 0.1% by mass of P.

[0039] <Fifth Embodiment> The aluminum alloy for casting according to the fifth embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.75% by mass of Mn, 0.01 to 0.80% by mass of Fe, and the balance is Al and unavoidable elements.

[0040] (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 caused by Fe, can be crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Further, since the lower limit of the Fe content is 0.01% by mass, the occurrence of seizure of the aluminum alloy when casting an aluminum casting by the die-casting method can be suppressed. Also, since the upper limit of the Fe content is 0.80% by mass, coarsening of the Fe-based intermetallic compound phase as a hard phase can be suppressed. Therefore, embrittlement of the aluminum alloy can be suppressed. Accordingly, a decrease in the tensile strength of the aluminum alloy can be suppressed. Further, since the upper limit of the Fe content is 0.80% by mass, a 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, generation of sludge during 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.

[0041] According to the aluminum alloy for casting of the present embodiment, by setting the Fe content to 0.01 to 0.80% by mass, the rigidity of the aluminum alloy can be improved and a decrease in tensile strength can be suppressed. Further, by setting the Mn content to 0.01 to 0.75% by mass, a decrease in the corrosion resistance of the aluminum casting due to Fe can be suppressed.

[0042] In the aluminum alloy for casting of the present embodiment, the lower limit of the Fe content is preferably 0.05% by mass, more preferably 0.10% by mass, 0.15% by mass, 0.20% by mass, 0.25% by mass, 0.29% by mass, 0.30% by mass, 0.31% by mass, 0.32% by mass or 0.34% by mass. Also, the upper limit of the Fe content is preferably 0.75% by mass, more preferably 0.70% by mass, 0.65% by mass, 0.60% by mass or 0.55% by mass. By setting the lower limit and the upper limit of the Fe content in this way, it is easy to improve both the rigidity and the tensile strength of the aluminum alloy. Alternatively, it is possible to suppress a situation in which either the rigidity or the tensile strength extremely decreases, and it is easy to balance the expression of both the rigidity and the tensile strength. The same applies to the following embodiments.

[0043] The aluminum alloy for casting of the present embodiment may further contain 5.0 to 20.0% by mass of Si. Also, the aluminum alloy for casting of the present embodiment may further contain 0.0001 to 0.1% by mass of P. Also, the aluminum alloy for casting of the present embodiment may further contain 0.01 to 3.0% by mass of Mg.

[0044] <Sixth Embodiment> The aluminum alloy for casting of the sixth embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.75% by mass of Mn, 0.0001 to 0.50% by mass of Cr, and the balance is Al and unavoidable elements.

[0045] (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. Also, since the upper limit of the Cr content is 0.50% by mass, coarsening of the Cr-based intermetallic compound phase, which is an intermetallic compound phase caused by Cr, can be suppressed. For this reason, embrittlement of the aluminum alloy can be suppressed. Furthermore, since the upper limit of the Cr content is 0.50% by mass, generation of sludge during casting of the aluminum casting can be suppressed. For this reason, 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, a decrease in the thermal conductivity and electrical conductivity of the aluminum casting can be suppressed. The same applies to the following embodiments.

[0046] In the aluminum alloy for casting according to the present embodiment, the lower limit of the Cr content is preferably 0.001% by mass, more preferably 0.005% by mass or 0.01% by mass. Also, the upper limit of the Cr content is preferably 0.30% by mass, more preferably 0.10% by mass, 0.07% by mass, 0.05% by mass or 0.03% by mass. The same applies to the following embodiments.

[0047] The aluminum alloy for casting according to the present embodiment may further contain 5.0 to 20.0% by mass of Si. Also, the aluminum alloy for casting according to the present embodiment may further contain 0.0001 to 0.1% by mass of P. Also, the aluminum alloy for casting according to the present embodiment may further contain 0.01 to 3.0% by mass of Mg. Also, the aluminum alloy for casting according to the present embodiment may further contain 0.01 to 0.80% by mass of Fe.

[0048] <The Seventh Embodiment> The aluminum alloy for casting according to the seventh embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.75% by mass of Mn, 0.0001 to 0.75% by mass of Ti, with the balance being Al and inevitable elements.

[0049] (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, it is easy to refine the crystal grains in the aluminum alloy. For this reason, it is easy to reduce the occurrence of shrinkage cavities and hot cracks in the aluminum casting and improve the heat resistance and mechanical properties. Also, since the upper limit of the Ti content is 0.75% by mass, coarsening of the Ti-based intermetallic compound phase, which is an intermetallic compound phase caused by Ti, can be suppressed. For this reason, a decrease in the toughness of the aluminum alloy can be suppressed. Furthermore, since the upper limit of the Ti content is 0.75% by mass, a decrease in the electrical conductivity of the aluminum casting can be suppressed. The same applies to the following embodiments.

[0050] In the aluminum alloy for casting according to the present embodiment, the lower limit of the Ti content is preferably 0.001% by mass, and more preferably 0.005% by mass, 0.01% by mass, 0.05% by mass or 0.10% by mass. Also, the upper limit of the Ti content is preferably 0.50% by mass, and more preferably 0.30% by mass or 0.20% by mass. The same applies to the following embodiments.

[0051] The aluminum alloy for casting according to the present embodiment may further contain 5.0 to 20.0% by mass of Si. Also, the aluminum alloy for casting according to the present embodiment may further contain 0.0001 to 0.1% by mass of P. Also, the aluminum alloy for casting according to the present embodiment may further contain 0.01 to 3.0% by mass of Mg. Also, the aluminum alloy for casting according to the present embodiment may further contain 0.01 to 0.80% by mass of Fe. Also, the aluminum alloy for casting according to the present embodiment may further contain 0.0001 to 0.50% by mass of Cr.

[0052] <Eighth Embodiment> The aluminum alloy for casting according to the eighth embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.75% by mass of Mn, and 0.0001 to 0.50% by mass of V, with the balance being Al and unavoidable elements.

[0053] (V: Vanadium) The aluminum alloy for casting according to the eighth embodiment contains 0.0001 to 0.50% by mass of V. Since the lower limit of the content of V is 0.0001% by mass, the heat resistance of the aluminum casting can be improved. Also, since the upper limit of the content of V is 0.50% by mass, a decrease in the electrical conductivity of the aluminum casting can be suppressed. The same applies to the following embodiments.

[0054] In the aluminum alloy for casting of the present embodiment, the lower limit of the content of V is preferably 0.001% by mass, more preferably 0.005% by mass or 0.01% by mass. Also, the upper limit of the content of V is preferably 0.30% by mass, more preferably 0.20% by mass, 0.10% by mass or 0.07% by mass. The same applies to the following embodiments.

[0055] The aluminum alloy for casting of the present embodiment may further contain 5.0 to 20.0% by mass of Si. Also, the aluminum alloy for casting of the present embodiment may further contain 0.0001 to 0.1% by mass of P. Also, the aluminum alloy for casting of the present embodiment may further contain 0.01 to 3.0% by mass of Mg. Also, the aluminum alloy for casting of the present embodiment may further contain 0.01 to 0.80% by mass of Fe. Also, the aluminum alloy for casting of the present embodiment may further contain 0.0001 to 0.50% by mass of Cr. Also, the aluminum alloy for casting of the present embodiment may further contain 0.0001 to 0.75% by mass of Ti.

[0056] <The Ninth Embodiment> The aluminum alloy for casting according to the ninth embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.80% by mass of Fe, and the balance is Al and inevitable elements.

[0057] According to the aluminum alloy for casting of the present embodiment, by setting the content of Ni to 1.0 to 10.0% by mass, Ni-based intermetallic compound phases can be dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Further, by setting the content of Cu to 8.01 to 18.0% by mass, Cu-based intermetallic compound phases can be crystallized in a network around the Ni-based intermetallic compound phases. Therefore, by coexisting Ni-based intermetallic compound phases and Cu-based intermetallic compound phases with different crystallization regions, the rigidity of the aluminum alloy can be further improved. In addition, the Cu-based intermetallic compound phases form a network around the Ni-based intermetallic compound phases, thereby improving the tensile strength of the aluminum alloy. Further, by setting the lower limit of the content of Fe to 0.01% by mass, Fe-based intermetallic compound phases can be crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Also, by setting the upper limit of the content of Fe to 0.80% by mass, coarsening of the Fe-based intermetallic compound phases as hard phases can be suppressed, and embrittlement of the aluminum alloy can be suppressed. Therefore, a decrease in the tensile strength of the aluminum alloy can be suppressed.

[0058] <Tenth Embodiment> The aluminum alloy for casting according to the tenth embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.80% by mass of Fe, 5.0 to 20.0% by mass of Si, and the balance is Al and inevitable elements.

[0059] According to the aluminum alloy for casting of the present embodiment, by setting the Si content to 5.0 to 20.0% by mass, primary crystal and eutectic Si phases can be dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Further, by setting the Ni content to 1.0 to 10.0% by mass, Ni-based intermetallic compound phases can be crystallized around the Si phase. Furthermore, by setting the Cu content to 8.01 to 18.0% by mass, Cu-based intermetallic compound phases can be crystallized in a network around the Si phase and Ni-based intermetallic compound phases. Therefore, by coexisting Si phases, Ni-based intermetallic compound phases, and Cu-based intermetallic compound phases with different crystallization regions, the rigidity of the aluminum alloy can be further improved. Furthermore, by setting the Fe content to 0.01 to 0.80% by mass, the rigidity of the aluminum alloy can be improved and a decrease in tensile strength can be suppressed.

[0060] <The 11th Embodiment> The aluminum alloy for casting of the 11th embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.80% by mass of Fe, 5.0 to 20.0% by mass of Si, and 0.0001 to 0.1% by mass of P, with the balance being Al and inevitable elements.

[0061] According to the aluminum alloy for casting of the present embodiment, by setting the P content to 0.0001 to 0.1% by mass, AlP (aluminum phosphide) generated in the aluminum alloy acts as a heterogeneous nucleus for primary crystal Si, so that the primary crystal Si can be refined. Therefore, it is easy to uniformly disperse and crystallize primary crystal Si in the aluminum alloy. Therefore, it is easy to suppress variations in rigidity and tensile strength in the aluminum alloy.

[0062] <The 12th Embodiment> The aluminum alloy for casting of the 12th embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.80% by mass of Fe, and 0.01 to 3.0% by mass of Mg, with the balance being Al and inevitable elements.

[0063] According to the aluminum alloy for casting of the present embodiment, by setting the Mg content to 0.01 to 3.0% by mass, it is possible to precipitate an Mg-based intermetallic compound phase, which is an intermetallic compound phase caused by Mg, by aging treatment. Therefore, the tensile strength of the aluminum alloy can be further improved.

[0064] The aluminum alloy for casting of the present embodiment may further contain 5.0 to 20.0% by mass of Si. Further, the aluminum alloy for casting of the present embodiment may further contain 0.0001 to 0.1% by mass of P.

[0065] <The 13th Embodiment> The aluminum alloy for casting of the 13th embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.80% by mass of Fe, 0.0001 to 0.50% by mass of Cr, and the balance is Al and unavoidable elements.

[0066] The aluminum alloy for casting of the present embodiment may further contain 5.0 to 20.0% by mass of Si. Further, the aluminum alloy for casting of the present embodiment may further contain 0.0001 to 0.1% by mass of P. Further, the aluminum alloy for casting of the present embodiment may further contain 0.01 to 3.0% by mass of Mg. Further, the aluminum alloy for casting of the present embodiment may further contain 0.01 to 0.75% by mass of Mn.

[0067] <The 14th Embodiment> The aluminum alloy for casting of the 14th embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.80% by mass of Fe, 0.0001 to 0.75% by mass of Ti, and the balance is Al and unavoidable elements.

[0068] The aluminum alloy for casting of the present embodiment may further contain 5.0 to 20.0% by mass of Si. Further, the aluminum alloy for casting of the present embodiment may further contain 0.0001 to 0.1% by mass of P. Further, the aluminum alloy for casting of the present embodiment may further contain 0.01 to 3.0% by mass of Mg. Further, the aluminum alloy for casting of the present embodiment may further contain 0.01 to 0.75% by mass of Mn. Further, the aluminum alloy for casting of the present embodiment may further contain 0.0001 to 0.50% by mass of Cr.

[0069] <The 15th Embodiment> The aluminum alloy for casting of the 15th embodiment contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.80% by mass of Fe, 0.0001 to 0.50% by mass of V, and the balance is Al and unavoidable elements.

[0070] The aluminum alloy for casting of the present embodiment may further contain 5.0 to 20.0% by mass of Si. Further, the aluminum alloy for casting of the present embodiment may further contain 0.0001 to 0.1% by mass of P. Further, the aluminum alloy for casting of the present embodiment may further contain 0.01 to 3.0% by mass of Mg. Further, the aluminum alloy for casting of the present embodiment may further contain 0.01 to 0.75% by mass of Mn. Further, the aluminum alloy for casting of the present embodiment may further contain 0.0001 to 0.50% by mass of Cr. Further, the aluminum alloy for casting of the present embodiment may further contain 0.0001 to 0.75% by mass of Ti.

[0071] By using the aluminum alloy for casting of the above embodiments, 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 that require high rigidity and high tensile strength. Examples of applications of this aluminum casting include components of machine tools, robots, and automobiles.

[0072] <Examples> Figure 1 shows the compositions (mass %), values of condition (1), values of condition (2), Young's modulus (GPa), and tensile strength (MPa) of some examples and comparative examples of the aluminum alloy for casting according to the above embodiments. In Figure 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. Also, the tensile strength (MPa) is a value measured according to "JIS Z 2241 (Test Method for Tensile Testing of Metallic Materials)" for test pieces of the aluminum alloy for casting according to the examples and comparative examples. As the test pieces, No. 14A test pieces with a diameter of 6 mm and a parallel portion length of 36 mm, which were cast by the permanent mold casting method, were used. Also, Young's modulus is a value obtained from the slope within the elastic range of the stress-strain relationship in the tensile test. The strain was taken as the average value of the measured values of two uniaxial strain gauges attached face-to-face to the surface of the parallel portion of the test piece.

[0073] (Comparison between Examples 1 to 10 and Comparative Example 1) As shown in Figure 1, the Cu content of Examples 1 to 10 is 8.01 mass % or more, while the Cu content of Comparative Example 1 is less than 8.01 mass %. Also, the Fe content of Examples 1 to 10 is 0.80 mass % or less, while the Fe content of Comparative Example 1 exceeds 0.80 mass %. Here, the Young's modulus of Examples 1 to 10 is 95 to 108 GPa, while the Young's modulus of Comparative Example 1 is 95 GPa. For this reason, in Examples 1 to 10, the rigidity is improved by up to about 14% compared to Comparative Example 1. Also, the tensile strength of Examples 1 to 10 is 170 to 261 MPa, while the tensile strength of Comparative Example 1 is 160 MPa. For this reason, in Examples 1 to 10, the tensile strength is improved by up to about 63% (at least about 6%) compared to Comparative Example 1. Thus, it was confirmed that 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 %, the rigidity and tensile strength of the aluminum alloy for casting can be improved.

[0074] (Comparison between Examples 1 to 10 and Comparative Example 2) As shown in Fig. 1, the Cu content of Examples 1 to 10 is 18.0 mass% or less, while 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, while the Young's modulus of Comparative Example 2 is 104 GPa. Therefore, in Examples 1 to 10, the variation range of rigidity is within 4 to 9% compared to Comparative Example 2. Also, the tensile strength of Examples 1 to 10 is 170 to 261 MPa, while the tensile strength of Comparative Example 2 is 119 MPa. Therefore, in Examples 1 to 10, the tensile strength is improved by up to about 120% (at least about 43%) compared to Comparative Example 2. Thus, it was confirmed that by setting the upper limit of the Cu content to 18.0 mass%, the variation in rigidity of the aluminum alloy for casting can be suppressed, the rigidity can be stably exhibited, and the tensile strength can be significantly improved.

[0075] (Comparison between Examples 1 to 10 and Comparative Example 3) As shown in Fig. 1, the Mn content of Examples 1 to 10 is 0.75 mass% or less, while 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, while the Young's modulus of Comparative Example 3 is 105 GPa. Therefore, in Examples 1 to 10, the variation range of rigidity is within 3 to 10% compared to Comparative Example 3. Also, the tensile strength of Examples 1 to 10 is 170 to 261 MPa, while the tensile strength of Comparative Example 3 is 153 MPa. Therefore, in Examples 1 to 10, the tensile strength is improved by up to about 71% (at least about 11%) compared to Comparative Example 3. Thus, it was confirmed that by setting the upper limit of the Mn content to 0.75 mass%, the variation in rigidity of the aluminum alloy for casting can be suppressed, the rigidity can be stably exhibited, and the tensile strength can be significantly improved.

[0076] (Comparison between Examples 2 to 9 and Example 1) As shown in Fig. 1, the Cu content of Examples 2 to 9 is 9.0 mass% or more, while 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, while the Young's modulus of Example 1 is 99 GPa. Therefore, in Examples 2 to 9, the variation range of rigidity is within the range of 4 to 9% compared to Example 1. Also, the tensile strength of Examples 2 to 9 is 181 to 261 MPa, while the tensile strength of Example 1 is 172 MPa. Therefore, in Examples 2 to 9, the tensile strength is improved by up to about 52% (at least about 5%) compared to Example 1. Thus, it was confirmed that by setting the lower limit of the Cu content to 9.0 mass%, the variation in rigidity of the aluminum alloy for casting can be suppressed, the rigidity can be stably exhibited, and the tensile strength can be improved.

[0077] (Comparison between Examples 2 to 9 and Example 10) As shown in Fig. 1, the Cu content of Examples 2 to 9 is 15.5 mass% or less, while 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, while the Young's modulus of Example 10 is 104 GPa. Therefore, in Examples 2 to 9, the variation range of rigidity is within the range of 4 to 9% compared to Example 10. Also, the tensile strength of Examples 2 to 9 is 181 to 261 MPa, while the tensile strength of Example 10 is 170 MPa. Therefore, in Examples 2 to 9, the tensile strength is improved by up to about 54% (at least about 6%) compared to Example 10. Thus, it was confirmed that by setting the upper limit of the Cu content to 15.5 mass%, the variation in rigidity of the aluminum alloy for casting can be suppressed, the rigidity can be stably exhibited, and the tensile strength can be improved.

[0078] (Microstructure of Aluminum Alloy for Casting) Figures 2 to 8 show the observation results of the microstructure of the test pieces of the aluminum alloy for casting. Figure 2 shows Comparative Example 1, Figure 3 shows Example 1, Figure 4 shows Example 2, Figure 5 shows Example 3, Figure 6 shows Example 8, Figure 7 shows Example 10, and Figure 8 shows the microstructure of Comparative Example 2, which are the results observed by a scanning electron microscope (SEM).

[0079] As shown in Figure 1, in Comparative Example 1, the Cu content is 4.74 mass%. As shown in Figure 2, in Comparative Example 1, fine 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. Also, 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 the parts where the Cu-based intermetallic compound phase 30 is crystallized, the adjacent Cu-based intermetallic compound phases 30 are discontinuously distributed in a state where they are interrupted from each other. As a result, as shown in Figure 1, in Comparative Example 1, it is difficult to improve the tensile strength of the aluminum alloy for casting.

[0080] As shown in Fig. 1, in Example 1, the Cu content is 8.20% by mass; in Example 2, the Cu content is 10.12% by mass; in Example 3, the Cu content is 11.88% by mass; in Example 8, the Cu content is 15.02% by mass; and in Example 10, the Cu content is 16.98% by mass. As shown in Figs. 3 to 7, in Examples 1, 2, 3, 8, and 10, the Cu-based intermetallic compound phase 30 crystallizes almost evenly throughout the aluminum alloy. Also, in Examples 1, 2, 3, 8, and 10, the adjacent Cu-based intermetallic compound phases 30 are continuously distributed in a connected state, and a network-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. Further, as shown in Figs. 4 to 6, in Examples 2, 3, and 8, the Cu-based intermetallic compound phase 30 itself that constitutes the network has grown thick, and the network-like network has expanded to be distributed almost throughout the aluminum alloy. As a result, as shown in Fig. 1, in Examples 2, 3, and 8, the tensile strength of the aluminum alloy for casting can be further improved.

[0081] As shown in Fig. 1, in Comparative Example 2, the Cu content is 18.5% by mass. As shown in Fig. 8, in Comparative Example 2, the Cu-based intermetallic compound phase 30 itself that constitutes the network has coarsened into a granular (blocky) shape, and the network-like network has been segmented and / or broken. As a result, as shown in Fig. 1, in Comparative Example 2, it is difficult to improve the tensile strength of the aluminum alloy for casting.

[0082] As a result of observing the microstructure of the test piece of the aluminum alloy for casting, it was confirmed that the Si phase 10, Ni-based intermetallic compound phase 20, and Cu-based intermetallic compound phase 30 with different crystallization regions can coexist. Also, by setting the Cu content to 8.01 to 18.0 mass%, it was confirmed that the Cu-based intermetallic compound phase 30 can be continuously crystallized in a network pattern around the Si phase 10 and Ni-based intermetallic compound phase 20. Furthermore, by setting the Cu content to 9.0 to 15.5 mass%, it was confirmed that a network-like network of the Cu-based intermetallic compound phase 30 can be formed over almost the entire area of the aluminum alloy. As a result, as shown in FIG. 1, in Examples 1 to 10, compared with Comparative Examples 1 and 2, the rigidity of the aluminum alloy for casting can be improved, or the rigidity can be stably exhibited with a small variation width, and at the same time, the tensile strength can be improved.

[0083] In addition, each composition in the above embodiments (the first embodiment to the fifteenth embodiment) can also be applied to the aluminum alloy powder for additive manufacturing. The aluminum alloy powder for additive manufacturing can be manufactured by various powder manufacturing methods such as the water atomization method, gas atomization method, disk atomization method, and plasma atomization method. Since this composition is the composition of an aluminum alloy, when powderizing the alloy of this composition, for example, the disk atomization method, which is suitable for powderizing low-melting-point materials, can be used.

[0084] By using the aluminum alloy powder for laminated molding to which each composition in the above embodiments (the first to fifteenth embodiments) is applied, it is possible to provide a laminated molded article having high rigidity and excellent tensile strength. Therefore, this laminated molded article is suitable for a wide variety of applications that require high rigidity and high tensile strength. Examples of the applications of this laminated molded article include, in addition to the examples of the applications of the above aluminum castings, aerospace equipment, transportation equipment, medical equipment, etc., and their components. The laminated molded article can be manufactured, for example, by using a metal 3D printer or the like and various three-dimensional laminated molding methods such as a powder bed method, a deposition method, and a binder jetting method.

[0085] Examples of aspects of the invention recognized from the present specification and drawings are shown below. One aspect of the present invention is an aluminum alloy for casting containing 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.75% by mass of Mn, with the balance being Al and inevitable elements.

[0086] According to this aluminum alloy for casting, by setting the Ni content to 1.0 to 10.0% by mass, it is possible to disperse and precipitate a Ni-based intermetallic compound phase, which is a flaky intermetallic compound phase caused by Ni, in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Further, by setting the Cu content to 8.01 to 18.0% by mass, a Cu-based intermetallic compound phase, which is an intermetallic compound phase caused by Cu, can be precipitated in a network form around the Ni-based intermetallic compound phase. Therefore, by coexisting the Ni-based intermetallic compound phase and the Cu-based intermetallic compound phase with different precipitation regions, the rigidity of the aluminum alloy can be further improved. In addition, since the Cu-based intermetallic compound phase forms a network around the Ni-based intermetallic compound phase, the tensile strength of the aluminum alloy can be improved. Furthermore, by setting the lower limit of the Mn content to 0.01% by mass, an Mn-based intermetallic compound phase, which is an intermetallic compound phase caused by Mn, can be precipitated in the aluminum alloy. Therefore, it is easy to improve the rigidity of the aluminum alloy. Also, by setting the upper limit of the Mn content to 0.75% by mass, coarsening of the Mn-based intermetallic compound phase as a hard phase can be suppressed, and embrittlement of the aluminum alloy can be easily suppressed. Therefore, a decrease in the tensile strength of the aluminum alloy can be easily suppressed.

[0087] The aluminum alloy for casting may contain 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.80% by mass of Fe, with the balance being Al and inevitable elements.

[0088] According to this aluminum alloy for casting, by setting the Ni content to 1.0 to 10.0% by mass, Ni-based intermetallic compound phases can be dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Further, by setting the Cu content to 8.01 to 18.0% by mass, Cu-based intermetallic compound phases can be crystallized in a network shape around the Ni-based intermetallic compound phases. Therefore, by coexisting Ni-based intermetallic compound phases and Cu-based intermetallic compound phases with different crystallization regions, the rigidity of the aluminum alloy can be further improved. In addition, since the Cu-based intermetallic compound phases form a network-shaped network around the Ni-based intermetallic compound phases, the tensile strength of the aluminum alloy can be improved. Furthermore, by setting the lower limit of the Fe content to 0.01% by mass, Fe-based intermetallic compound phases, which are intermetallic compound phases caused by Fe, can be crystallized in the aluminum alloy. Therefore, it is easy to improve the rigidity of the aluminum alloy. Also, by setting the upper limit of the Fe content to 0.80% by mass, coarsening of the Fe-based intermetallic compound phases as hard phases can be suppressed, and embrittlement of the aluminum alloy can be easily suppressed. Therefore, it is easy to suppress a decrease in the tensile strength of the aluminum alloy.

[0089] In the above aluminum alloy for casting, the Ni content is preferably 3.0 to 10.0% by mass. By setting the lower limit of the Ni content to 3.0% by mass, Ni-based intermetallic compound phases can be more dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be further improved.

[0090] In the above 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)

[0091] The above aluminum alloy for casting preferably further contains 5.0 to 20.0% by mass of Si. By setting the Si content to 5.0 to 20.0% by mass, Si phases can be dispersed and crystallized in the aluminum alloy. Therefore, the rigidity of the aluminum alloy can be improved. Further, by setting the Ni content to 1.0 to 10.0% by mass, Ni-based intermetallic compound phases can be crystallized around the Si phases. Further, by setting the Cu content to 8.01 to 18.0% by mass, Cu-based intermetallic compound phases can be crystallized in a network around the Si phases and Ni-based intermetallic compound phases. Therefore, by coexisting Si phases, Ni-based intermetallic compound phases, and Cu-based intermetallic compound phases with different crystallization regions, the rigidity of the aluminum alloy can be further improved.

[0092] In the above aluminum alloy for casting, the Si content is preferably 5.0 to 14.5% by mass. By setting the upper limit of the Si content to 14.5% by mass, coarsening of the Si phases during the solidification process of the aluminum alloy can be suppressed, and embrittlement of the aluminum alloy can be easily suppressed. Therefore, the tensile strength of the aluminum alloy can be easily improved.

[0093] In the above 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)

[0094] The above aluminum alloy for casting preferably further contains 0.0001 to 0.1% by mass of P. By setting the P content to 0.0001 to 0.1% by mass, AlP (aluminum phosphide) generated in the aluminum alloy acts as a heterogeneous nucleus for primary Si, so that primary Si can be refined. Therefore, it is easy to uniformly disperse and crystallize primary Si in the aluminum alloy. Therefore, variations in rigidity and tensile strength in the aluminum alloy can be easily suppressed.

[0095] The above aluminum alloy for casting preferably further contains 0.01 to 3.0% by mass of Mg. By setting the content of Mg to 0.01 to 3.0% by mass, it is possible to precipitate an Mg-based intermetallic compound phase, which is an intermetallic compound phase caused by Mg, by aging treatment. Therefore, the tensile strength of the aluminum alloy can be further improved.

[0096] In the above aluminum alloy for casting, the content of Cu is preferably 9.0 to 15.5% by mass.

[0097] Another aspect of the present invention is an aluminum casting cast using the above aluminum alloy for casting. It is possible to provide an aluminum casting having high rigidity and excellent tensile strength.

[0098] Another aspect of the present invention is an aluminum alloy powder for additive manufacturing, which contains 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.75% by mass of Mn, and the balance is Al and unavoidable elements. The aluminum alloy powder for additive manufacturing may contain 1.0 to 10.0% by mass of Ni, 8.01 to 18.0% by mass of Cu, 0.01 to 0.80% by mass of Fe, and the balance is Al and unavoidable elements.

[0099] Another aspect of the present invention is an additive manufactured object additive manufactured using the above aluminum alloy powder for additive manufacturing. It is possible to provide an additive manufactured object having high rigidity and excellent tensile strength.

Explanation of Reference Numerals

[0100] 10 Si phase 20 Ni-based intermetallic compound phase 30 Cu-based intermetallic compound phase

Claims

1. 1. A casting aluminum alloy comprising: 2.1 to 10.0 mass% Ni, 10.1 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.

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, 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)

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

7. 2. The casting aluminum alloy according to claim 1, wherein the Cu content is 10.1 to 15.5 mass%.

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

9. An aluminum alloy powder for additive manufacturing comprising 2.1 to 10.0 mass% Ni, 10.1 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 remainder being Al and unavoidable elements.

10. The aluminum alloy powder for additive manufacturing according to claim 9, wherein the Ni content is 3.0 to 10.0 mass%.

11. The aluminum alloy powder for additive manufacturing according to claim 9, wherein the Cu content [Cu] and the Ni content [Ni] satisfy the following condition (1). 10.0≦[Cu]+0.87[Ni]≦23.5...(1)

12. The aluminum alloy powder for additive manufacturing according to claim 9, wherein the Si content is 5.0 to 14.5 mass%.

13. The aluminum alloy powder for additive manufacturing according to claim 9, 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)

14. The aluminum alloy powder for additive manufacturing according to claim 9, further containing 0.0001 to 0.1 mass% P.

15. The aluminum alloy powder for additive manufacturing according to claim 9, wherein the Cu content is 10.1 to 15.5 mass%.

16. A laminated object produced by laminate manufacturing using the aluminum alloy powder for laminate manufacturing according to any one of claims 9 to 15.

Images