JP2020056059A - Aluminum alloy and manufacturing method therefor - Google Patents
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本発明は、耐熱性に優れたアルミニウム合金、及びその製造方法に関するものである。 The present invention relates to an aluminum alloy having excellent heat resistance and a method for producing the same.
近年、ＣＯ2削減による地球環境に対する配慮や、省エネルギーの観点から、自動車や二輪車などの輸送機において、各種構造部材の軽量化及びコストダウンの要求が高まり、各種部材の材料を鉄鋼からアルミニウム合金へ切り替えるための開発が行われている。その中でも、エンジンなどに搭載される内燃機関用部品に用いられるアルミニウム合金には、室温環境だけではなく、高温環境下における高強度化が要求されている。 In recent years, from the viewpoint of consideration for the global environment by reducing CO 2 and energy saving, in transport vehicles such as automobiles and motorcycles, the demand for weight reduction and cost reduction of various structural members has increased, and the material of various members has been changed from steel to aluminum alloy. Development to switch is underway. Among them, aluminum alloys used for internal combustion engine parts mounted on engines and the like are required to have high strength not only at room temperature but also at high temperature.
エンジン部品用のアルミニウム合金には、ＡＡ規格のＡＡ２６１８、ＡＡ２２１９合金が適用されている。これまで、２００℃付近までの高温強度を確保するために、Ｃｕ、Ｍｇ及びＮｉを主要成分とするアルミニウム合金に、Ａｇを添加して高強度化する試みが行われている（特許文献１）。また、アルミニウム合金の高強度化として、アルミニウム合金の溶融開始温度を基に、溶体化処理温度を設定することで、過飽和固溶量を増大させ、時効処理時の微細析出物の析出量の増加によりアルミニウム合金を高強度化する試みが行われている（特許文献２）。 AA2618 and AA2219 alloys of AA standard are applied to aluminum alloys for engine parts. Until now, in order to secure high-temperature strength up to around 200 ° C., attempts have been made to increase the strength by adding Ag to an aluminum alloy containing Cu, Mg and Ni as main components (Patent Document 1). . In addition, to increase the strength of the aluminum alloy, by setting the solution treatment temperature based on the melting start temperature of the aluminum alloy, the amount of supersaturated solid solution is increased, and the precipitation amount of fine precipitates during aging treatment is increased. Attempts have been made to increase the strength of aluminum alloys by using such techniques (Patent Document 2).
しかしながら、特許文献１のＡｇを添加する手法には、Ａｇの地金が高価なため、製造コストが増大するという問題がある。また、特許文献２では、アルミニウム合金の溶融開始温度近傍で溶体化処理を行うため、局所的に溶融開始温度まで加熱されて、アルミニウム合金が部分溶解し、また、高温加熱によりアルミニウム合金の組織が部分再結晶して、強度低下につながるおそれがある。 However, the method of adding Ag disclosed in Patent Document 1 has a problem that the production cost increases because the Ag base metal is expensive. In Patent Document 2, since the solution treatment is performed in the vicinity of the melting start temperature of the aluminum alloy, the aluminum alloy is locally heated to the melting start temperature, and the aluminum alloy is partially melted. Partial recrystallization may lead to a decrease in strength.
従って、本発明の目的は、Ａｌ−Ｃｕ−Ｍｇ系アルミニウム合金であり、耐熱性に優れる高強度アルミニウム合金を提供することにある。 Therefore, an object of the present invention is to provide a high-strength aluminum alloy which is an Al-Cu-Mg-based aluminum alloy and has excellent heat resistance.
本発明者らは、合金成分と、加工及び処理と、内部組織等との関連を検討した結果、合金成分、特にＣｕ、Ｍｇの含有量を特定の範囲とすること、溶体化処理を二段処理とすること等により、アルミニウム合金を高強度化するとともに、再結晶粒の粗大化を抑え、平均アスペクト比が５以上の繊維状組織を形成させることができ、そのことにより、耐熱性に優れる高強度のアルミニウム合金が得られることを見出し、本発明を完成させた。 The present inventors have studied the relationship between the alloy component, processing and treatment, and the internal structure and the like. As a result, the content of the alloy component, particularly Cu and Mg, is set to a specific range, and the solution treatment is performed in two steps. By performing the treatment, the strength of the aluminum alloy can be increased, the coarsening of the recrystallized grains can be suppressed, and a fibrous structure having an average aspect ratio of 5 or more can be formed, thereby having excellent heat resistance. The inventors have found that a high-strength aluminum alloy can be obtained, and have completed the present invention.
すなわち、本発明（１）は、Ｃｕ：２．０〜３．５質量％、Ｓｉ：０．１〜０．５質量％、Ｆｅ：０．５〜１．０質量％、Ｍｎ：０．３〜０．８質量％、Ｍｇ：１．５〜２．５質量％、Ｔｉ：０．０５〜０．３質量％、Ｎｉ：０．５〜２．０質量％、及びＺｒ：０．０５〜０．３質量％を含有し、残部が不可避不純物及びアルミニウムからなり、塑性加工方向に平行な断面の結晶粒の平均アスペクト比が５以上の繊維組織であることを特徴とするアルミニウム合金を提供するものである。 That is, in the present invention (1), Cu: 2.0 to 3.5% by mass, Si: 0.1 to 0.5% by mass, Fe: 0.5 to 1.0% by mass, Mn: 0.3. -0.8 mass%, Mg: 1.5-2.5 mass%, Ti: 0.05-0.3 mass%, Ni: 0.5-2.0 mass%, and Zr: 0.05- An aluminum alloy containing 0.3% by mass, the balance being unavoidable impurities and aluminum, and having an average aspect ratio of crystal grains having a cross section parallel to the direction of plastic working of 5 or more. Things.
また、本発明（２）は、更に、Ｓｃ：０．０５〜０．３質量％を含有することを特徴とする（１）のアルミニウム合金を提供するものである。 Further, the present invention (2) provides the aluminum alloy of (1), further containing Sc: 0.05 to 0.3% by mass.
また、本発明（３）は、２５℃での引張強さ（Ａ）が４８０ＭＰａ以上であり、且つ、２５℃での引張強さ（Ａ）と、２００℃の温度で１０時間暴露保持した後、２５℃で測定したときの引張強さ（Ｂ）との差（Ａ−Ｂ）が５０ＭＰａ以下であることを特徴とする（１）又は（２）いずれかのアルミニウム合金を提供するものである。 Further, the present invention (3) has a tensile strength (A) at 25 ° C. of 480 MPa or more, and a tensile strength (A) at 25 ° C., and after exposure and holding at a temperature of 200 ° C. for 10 hours. The present invention provides any one of (1) and (2), wherein the difference (AB) from the tensile strength (B) measured at 25 ° C. and 25 ° C. is 50 MPa or less. .
また、本発明（４）は、Ｃｕ：２．０〜３．５質量％、Ｓｉ：０．１〜０．５質量％、Ｆｅ：０．５〜１．０質量％、Ｍｎ：０．３〜０．８質量％、Ｍｇ：１．５〜２．５質量％、Ｔｉ：０．０５〜０．３質量％、Ｎｉ：０．５〜２．０質量％、及びＺｒ：０．０５〜０．３質量％を含有し、残部が不可避不純物及びアルミニウムからなるアルミニウム合金の鋳塊を、４００〜５２０℃の温度で１〜２０時間保持する均質化処理と、
該均質化処理を行い得られる均質化処理材を、３００〜５００℃の温度で熱間加工する熱間加工工程と、
該熱間加工工程を行い得られる熱間加工材を、該熱間加工材の溶融開始温度より１０〜２０℃低い温度域で、０．５〜５時間保持する一段目の溶体化処理と、該一段目の溶体化処理温度より５〜１０℃高い温度域で、０．５〜５時間保持する二段目の溶体化処理と、を続けて行った後、水冷して焼入れする二段溶体化処理と、
該二段溶体化処理を行い得られる二段溶体化処理材を、１５０〜２２０℃の温度で、２〜３０時間保持する人工時効処理と、
を有することを特徴とするアルミニウム合金の製造方法を提供するものである。
Further, the present invention (4) is characterized in that Cu: 2.0 to 3.5% by mass, Si: 0.1 to 0.5% by mass, Fe: 0.5 to 1.0% by mass, and Mn: 0.3. -0.8 mass%, Mg: 1.5-2.5 mass%, Ti: 0.05-0.3 mass%, Ni: 0.5-2.0 mass%, and Zr: 0.05- A homogenization treatment of holding an ingot of an aluminum alloy containing 0.3% by mass and the balance consisting of unavoidable impurities and aluminum at a temperature of 400 to 520 ° C. for 1 to 20 hours;
A hot working step of hot working the homogenized material obtained by performing the homogenizing process at a temperature of 300 to 500 ° C;
A first-stage solution treatment in which the hot-worked material obtained by performing the hot-working step is held for 0.5 to 5 hours in a temperature range lower by 10 to 20 ° C. than the melting start temperature of the hot-worked material; A second stage solution treatment in which the second stage solution treatment is performed in a temperature range higher by 5 to 10 ° C. than the first stage solution treatment temperature for 0.5 to 5 hours, followed by water cooling and quenching. Conversion processing,
An artificial aging treatment in which the two-step solution treatment material obtained by performing the two-step solution treatment is kept at a temperature of 150 to 220 ° C. for 2 to 30 hours;
And a method for producing an aluminum alloy.
本発明によれば、Ａｌ−Ｃｕ−Ｍｇ系アルミニウム合金であり、耐熱性に優れる高強度アルミニウム合金を提供することができる。 According to the present invention, a high-strength aluminum alloy which is an Al-Cu-Mg-based aluminum alloy and has excellent heat resistance can be provided.
本発明のアルミニウム合金は、Ｃｕ：２．０〜３．５質量％、Ｓｉ：０．１〜０．５質量％、Ｆｅ：０．５〜１．０質量％、Ｍｎ：０．３〜０．８質量％、Ｍｇ：１．５〜２．５質量％、Ｔｉ：０．０５〜０．３質量％、Ｎｉ：０．５〜２．０質量％、及びＺｒ：０．０５〜０．３質量％を含有し、残部が不可避不純物及びアルミニウムからなり、塑性加工方向に平行な断面の結晶粒の平均アスペクト比が５以上の繊維組織であることを特徴とするアルミニウム合金である。 The aluminum alloy of the present invention contains Cu: 2.0 to 3.5% by mass, Si: 0.1 to 0.5% by mass, Fe: 0.5 to 1.0% by mass, and Mn: 0.3 to 0%. 0.8% by mass, Mg: 1.5 to 2.5% by mass, Ti: 0.05 to 0.3% by mass, Ni: 0.5 to 2.0% by mass, and Zr: 0.05 to 0. An aluminum alloy containing 3% by mass, the balance being made of unavoidable impurities and aluminum, and having an average aspect ratio of crystal grains having a cross section parallel to the plastic working direction of 5 or more.
本発明のアルミニウム合金は、Ｃｕ、Ｓｉ、Ｆｅ、Ｍｎ、Ｍｇ、Ｔｉ、Ｎｉ、及びＺｒを、必須成分として含有し、残部不可避不純物及びアルミニウムからなる。また、本発明のアルミニウム合金は、必要に応じて、これらの成分に加えて、更に、Ｓｃを含有することができる。 The aluminum alloy of the present invention contains Cu, Si, Fe, Mn, Mg, Ti, Ni, and Zr as essential components, and the balance consists of unavoidable impurities and aluminum. Further, the aluminum alloy of the present invention can further contain Sc in addition to these components as necessary.
本発明のアルミニウム合金のＣｕ含有量は、２．０〜３．５質量％、好ましくは２．５〜３．３質量％である。Ｃｕは引張強さや疲労強度などの機械的性質の向上に寄与する元素である。アルミニウム合金のＣｕ含有量が上記範囲にあることにより、引張強さが高くなる。一方、アルミニウム合金のＣｕ含有量が、上記範囲未満だと、強度向上の効果が小さくなり、また、上記範囲を超えると、融点が大幅に低くなるため、溶体化処理温度を低くしなければならず、そのため、溶体化処理後のマトリックス中の過飽和度が小さくなり、強度向上の効果が得られない。 The Cu content of the aluminum alloy of the present invention is 2.0 to 3.5% by mass, preferably 2.5 to 3.3% by mass. Cu is an element that contributes to improvement of mechanical properties such as tensile strength and fatigue strength. When the Cu content of the aluminum alloy is in the above range, the tensile strength increases. On the other hand, if the Cu content of the aluminum alloy is less than the above range, the effect of improving strength is reduced, and if it exceeds the above range, the melting point is significantly reduced, so the solution treatment temperature must be lowered. Therefore, the degree of supersaturation in the matrix after the solution treatment becomes small, and the effect of improving the strength cannot be obtained.
本発明のアルミニウム合金のＳｉ含有量は、０．１〜０．５質量％、好ましくは０．２〜０．４質量％である。ＳｉはＭｎとともにＡｌ−Ｍｎ−Ｓｉ系化合物の微細分散相を析出させ、転位のピンニング効果を高めて、溶体化処理中の再結晶粒の粗大化を防止する。アルミニウム合金のＳｉ含有量が上記範囲にあることにより、高温強度が高くなる。一方、アルミニウム合金のＳｉ含有量が、上記範囲未満だと、強度向上の効果が小さくなり、また、上記範囲を超えると、粗大な化合物を形成するため、高温強度が低くなる。 The Si content of the aluminum alloy of the present invention is 0.1 to 0.5% by mass, preferably 0.2 to 0.4% by mass. Si precipitates a finely dispersed phase of an Al-Mn-Si compound together with Mn, enhances the pinning effect of dislocation, and prevents coarsening of recrystallized grains during solution treatment. When the Si content of the aluminum alloy is in the above range, the high-temperature strength is increased. On the other hand, if the Si content of the aluminum alloy is less than the above range, the effect of improving the strength is reduced, and if it exceeds the above range, a coarse compound is formed, and the high-temperature strength is reduced.
本発明のアルミニウム合金のＦｅ含有量は、０．５〜１．０質量％、好ましくは０．６〜０．９質量％である。ＦｅはＮｉとの化合物を形成し、耐熱性を向上させる。アルミニウム合金のＦｅ含有量が上記範囲にあることにより、耐熱性が高くなる。一方、アルミニウム合金のＦｅ含有量が、上記範囲未満だと、耐熱性の向上効果が小さくなり、また、上記範囲を超えると、Ａｌ−Ｆｅ系、Ａｌ−Ｆｅ−Ｃｕ系などのＦｅ系化合物がマトリックス中に分散するため、耐熱性の向上効果が小さくなる。 The Fe content of the aluminum alloy of the present invention is 0.5 to 1.0% by mass, preferably 0.6 to 0.9% by mass. Fe forms a compound with Ni and improves heat resistance. When the Fe content of the aluminum alloy is in the above range, heat resistance is increased. On the other hand, when the Fe content of the aluminum alloy is less than the above range, the effect of improving heat resistance is reduced, and when the Fe content exceeds the above range, Fe-based compounds such as Al-Fe-based and Al-Fe-Cu-based compounds are used. Since the particles are dispersed in the matrix, the effect of improving heat resistance is reduced.
本発明のアルミニウム合金のＭｎ含有量は、０．３〜０．８質量％、好ましくは０．４〜０．７質量％である。Ｍｎは機械的性質を向上させるとともに、Ｓｉとともに微細なＡｌ−Ｍｎ−Ｓｉ系化合物を析出し、分散することで、合金の溶体化処理中に生じる再結晶が抑制され、繊維状組織が形成され、強度を向上させる。アルミニウム合金のＭｎ含有量が上記範囲にあることにより、強度及び耐熱性が高くなる。一方、アルミニウム合金のＭｎ含有量が、上記範囲未満だと、強度及び耐熱性の向上効果が小さくなり、また、上記範囲を超えると、鋳造時に巨大晶出物が発生し易くなり、強度低下を招く。 The Mn content of the aluminum alloy of the present invention is 0.3 to 0.8% by mass, preferably 0.4 to 0.7% by mass. Mn improves mechanical properties and precipitates and disperses a fine Al-Mn-Si-based compound together with Si, thereby suppressing recrystallization occurring during the solution treatment of the alloy and forming a fibrous structure. Improve strength. When the Mn content of the aluminum alloy is within the above range, strength and heat resistance are increased. On the other hand, if the Mn content of the aluminum alloy is less than the above range, the effect of improving strength and heat resistance is reduced, and if it exceeds the above range, giant crystals are easily generated at the time of casting, and the strength is reduced. Invite.
本発明のアルミニウム合金のＭｇ含有量は、１．５〜２．５質量％、好ましくは１．７〜２．１質量％である。Ｍｇは機械的性質を向上させる。アルミニウム合金のＭｇ含有量が上記範囲にあることにより、強度が高くなる。一方、アルミニウム合金のＭｇ含有量が、上記範囲未満だと、強度向上の効果が小さくなり、また、上記範囲を超えると、成形加工性が悪くなり、生産性が低くなる。 The Mg content of the aluminum alloy of the present invention is 1.5 to 2.5% by mass, preferably 1.7 to 2.1% by mass. Mg improves mechanical properties. When the Mg content of the aluminum alloy is within the above range, the strength is increased. On the other hand, if the Mg content of the aluminum alloy is less than the above range, the effect of improving the strength will be small, and if it exceeds the above range, the moldability will be poor and the productivity will be low.
本発明のアルミニウム合金のＴｉ含有量は、０．０５〜０．３質量％、好ましくは０．１〜０．２質量％である。Ｔｉは微細な金属間化合物を形成し、微細結晶粒組織が安定して得られる。アルミニウム合金のＴｉ含有量が上記範囲にあることにより、アルミニウム合金の鋳塊に粗大な化合物が生じることが抑制されるため、高い成形性を維持できる。一方、アルミニウム合金のＴｉ含有量が、上記範囲未満だと、上記効果が小さくなり、上記範囲を超えると、成形加工性が悪くなる。また、Ｔｉは単独で添加するか、Ｂと組み合わせて複合添加して含有させてもよい。結晶粒微細化のためにはＢを併せて含有することで、より大きな効果が得られる。 The Ti content of the aluminum alloy of the present invention is 0.05 to 0.3% by mass, preferably 0.1 to 0.2% by mass. Ti forms a fine intermetallic compound, and a fine crystal grain structure can be stably obtained. When the Ti content of the aluminum alloy is in the above range, generation of a coarse compound in the ingot of the aluminum alloy is suppressed, so that high formability can be maintained. On the other hand, when the Ti content of the aluminum alloy is less than the above range, the above effects are reduced, and when the Ti content exceeds the above range, the formability is deteriorated. Further, Ti may be added alone or in combination with B to be added in combination. Greater effects can be obtained by additionally containing B for crystal grain refinement.
本発明のアルミニウム合金のＮｉ含有量は、０．５〜２．０質量％、好ましくは０．８〜１．３質量％である。ＮｉはＦｅとの化合物を形成し、耐熱性を向上させる。アルミニウム合金のＮｉ含有量が上記範囲にあることにより、耐熱性が高くなる。一方、アルミニウム合金のＮｉ含有量が、上記範囲未満だと、耐熱性の向上効果が小さくなり、また、上記範囲を超えると、Ａｌ−Ｎｉ系、Ａｌ−Ｎｉ−Ｃｕ系などのＮｉ系化合物がマトリックス中に分散するため、高温強度が低くなる。 The Ni content of the aluminum alloy of the present invention is 0.5 to 2.0% by mass, preferably 0.8 to 1.3% by mass. Ni forms a compound with Fe and improves heat resistance. When the Ni content of the aluminum alloy is in the above range, heat resistance is increased. On the other hand, when the Ni content of the aluminum alloy is less than the above range, the effect of improving heat resistance is reduced, and when the Ni content exceeds the above range, Ni-based compounds such as Al-Ni-based and Al-Ni-Cu-based compounds are used. Due to the dispersion in the matrix, the high temperature strength is reduced.
本発明のアルミニウム合金のＺｒ含有量は、０．０５〜０．３質量％、好ましくは０．１〜０．２質量％である。ＺｒはＡｌ3Ｚｒ化合物の微細分散により、溶体化処理中に生じる再結晶粒の粗大化を抑制し、繊維状組織を形成させて、強度を高める。アルミニウム合金のＺｒ含有量が上記範囲にあることにより、強度が高くなる。一方、アルミニウム合金のＺｒ含有量が、上記範囲未満だと、強度向上の効果が小さくなり、また、上記範囲を超えると、鋳造時に巨大晶出物が発生し、成形性が悪くなる。 The Zr content of the aluminum alloy of the present invention is 0.05 to 0.3% by mass, preferably 0.1 to 0.2% by mass. Zr suppresses coarsening of recrystallized grains generated during the solution treatment due to fine dispersion of the Al 3 Zr compound, forms a fibrous structure, and increases strength. When the Zr content of the aluminum alloy is within the above range, the strength increases. On the other hand, if the Zr content of the aluminum alloy is less than the above range, the effect of improving strength is reduced, and if it exceeds the above range, giant crystals are generated at the time of casting and the formability is deteriorated.
本発明のアルミニウム合金がＳｃを含有する場合、本発明のアルミニウム合金のＳｃ含有量は、０．０５〜０．３質量％、好ましくは０．１〜０．２質量％である。ＳｃはＡｌ3Ｓｃ化合物の微細分散により、溶体化処理中に生じる再結晶粒の粗大化を抑制するとともに、３００℃付近で析出硬化に寄与するため、耐熱性が高くなる。アルミニウム合金のＳｃ含有量が上記範囲にあることにより、耐熱性が高くなる。一方、アルミニウム合金のＳｃ含有量が、上記範囲未満だと、耐熱性の向上効果が小さくなり、また、上記範囲を超えると、微細に析出せずに、粗大化合物を形成し強度が低くなる。 When the aluminum alloy of the present invention contains Sc, the Sc content of the aluminum alloy of the present invention is 0.05 to 0.3% by mass, preferably 0.1 to 0.2% by mass. Sc suppresses the coarsening of recrystallized grains generated during the solution treatment due to the fine dispersion of the Al 3 Sc compound, and also contributes to precipitation hardening at around 300 ° C., thereby increasing the heat resistance. When the Sc content of the aluminum alloy is in the above range, heat resistance is increased. On the other hand, if the Sc content of the aluminum alloy is less than the above range, the effect of improving the heat resistance will be small, and if it exceeds the above range, a coarse compound will be formed without fine precipitation and the strength will be low.
本発明のアルミニウム合金は、塑性加工方向に平行な断面の結晶粒の平均アスペクト比が５以上の繊維組織である。アルミニウム合金が、塑性加工方向に平行な断面の結晶粒の平均アスペクト比が５以上の繊維組織（例えば、図１に示す組織）であることにより、耐熱性が高くなる。一方、アルミニウム合金の塑性加工方向に再結晶組織（例えば、図２に示す組織)を形成し、平行な断面の結晶粒の平均アスペクト比が５未満だと、耐熱性が低くなる。なお、本発明において、塑性加工方向に平行な断面の結晶粒の平均アスペクト比は、以下の測定方法により求められる。各試験材の塑性加工方向に平行な断面を電解エッチングし結晶粒を現出させ、材料組織を偏光光学顕微鏡により、倍率２５倍で撮影する。次いで、撮影写真上に観察される結晶粒から、任意に１０個選択し、個々の結晶粒について、「（塑性加工方向の長さ）／（塑性加工方向に直行する方向の長さ）」の式により、アスペクト比を計算し、選択した１０個の結晶粒の平均を求めて、平均アスペクト比とする。アスペクト比が十分に大きく、全ての結晶粒の塑性加工方向の長さが撮影視野を超え、アスペクト比が５以上と判断できる場合は、平均アスペクト比は５以上とする。 The aluminum alloy of the present invention has a fiber structure in which the average aspect ratio of crystal grains having a cross section parallel to the plastic working direction is 5 or more. When the aluminum alloy has a fiber structure (for example, the structure shown in FIG. 1) in which the average aspect ratio of the crystal grains having a cross section parallel to the plastic working direction is 5 or more, heat resistance is increased. On the other hand, when a recrystallized structure (for example, the structure shown in FIG. 2) is formed in the direction of plastic working of the aluminum alloy, and the average aspect ratio of the crystal grains in the parallel cross section is less than 5, heat resistance becomes low. In the present invention, the average aspect ratio of the crystal grains having a cross section parallel to the plastic working direction is determined by the following measuring method. A cross section parallel to the plastic working direction of each test material is electrolytically etched to reveal crystal grains, and the material structure is photographed with a polarizing optical microscope at a magnification of 25 times. Next, ten crystal grains are arbitrarily selected from the crystal grains observed on the photographed photograph, and for each crystal grain, “(length in the plastic working direction) / (length in the direction perpendicular to the plastic working direction)” The aspect ratio is calculated according to the formula, and the average of the selected 10 crystal grains is determined to be the average aspect ratio. If the aspect ratio is sufficiently large, the length of all the crystal grains in the plastic working direction exceeds the visual field of view, and it can be determined that the aspect ratio is 5 or more, the average aspect ratio is 5 or more.
本発明のアルミニウム合金は、２５℃での引張強さ（Ａ）が４８０ＭＰａ以上であり、且つ、２５℃での引張強さ（Ａ）と、２００℃の温度で１０時間暴露保持した後、２５℃で測定したときの引張強さ（Ｂ）との差（Ａ−Ｂ）が５０ＭＰａ以下である。エンジンなどに搭載される内燃機関用部品は、高温環境下で長時間用いられると、強度が低下するおそれがある。そして、本発明のアルミニウム合金は、２５℃での引張強さ（Ａ）が４８０ＭＰａ以上であり、且つ、２５℃での引張強さ（Ａ）と、２００℃の温度で１０時間暴露保持した後、２５℃で測定したときの引張強さ（Ｂ）との差（Ａ−Ｂ）が５０ＭＰａ以下であることにより、高強度であり、且つ、高温環境下での部品の強度低下を最小限度に抑え、製品寿命を延ばすことができる。なお、引張強さ（Ｂ）は、試験対象を、１００℃／時間の昇温速度で、２００℃まで加熱し、次いで、２００℃で１０時間保持し、次いで、空冷して、室温程度まで冷却した後、２５℃で試験対象を測定したときの引張強さである。また、引張強さ（Ａ）は、試験対象に上記のような加熱処理を施す前に、２５℃で試験対象を測定したときの引張強さである。 The aluminum alloy of the present invention has a tensile strength (A) at 25 ° C. of 480 MPa or more, and has a tensile strength (A) at 25 ° C. and a temperature of 200 ° C. for 10 hours. The difference (AB) from the tensile strength (B) when measured at ° C. is 50 MPa or less. When used for a long time in a high-temperature environment, components for internal combustion engines mounted on engines and the like may have reduced strength. The aluminum alloy of the present invention has a tensile strength (A) at 25 ° C. of 480 MPa or more, and a tensile strength (A) at 25 ° C., and after exposure and holding at a temperature of 200 ° C. for 10 hours. , The difference (A-B) from the tensile strength (B) measured at 25 ° C. is 50 MPa or less, thereby achieving high strength and minimizing the decrease in the strength of the part in a high-temperature environment. Control and extend product life. The tensile strength (B) was determined by heating the test object to 200 ° C. at a rate of temperature increase of 100 ° C./hour, holding the test object at 200 ° C. for 10 hours, then air cooling, and cooling to about room temperature. And the tensile strength when the test object is measured at 25 ° C. Further, the tensile strength (A) is a tensile strength when the test object is measured at 25 ° C. before subjecting the test object to the heat treatment as described above.
本発明のアルミニウム合金には、上記以外の元素が、不可避不純物元素として含有されていてもよい。本発明のアルミニウム合金中の不可避不純物元素の含有量は、本発明の効果が損なわれない範囲であれば、特に制限されず、それぞれの不可避不純物元素の含有量が０．０５質量％以下であることが好ましい。 Elements other than the above may be contained in the aluminum alloy of the present invention as unavoidable impurity elements. The content of the inevitable impurity elements in the aluminum alloy of the present invention is not particularly limited as long as the effects of the present invention are not impaired, and the content of each inevitable impurity element is 0.05% by mass or less. Is preferred.
本発明のアルミニウム合金は、例えば、以下に示す本発明のアルミニウム合金の製造方法により、製造される。 The aluminum alloy of the present invention is produced, for example, by the following method for producing an aluminum alloy of the present invention.
本発明のアルミニウム合金の製造方法は、Ｃｕ：２．０〜３．５質量％、Ｓｉ：０．１〜０．５質量％、Ｆｅ：０．５〜１．０質量％、Ｍｎ：０．３〜０．８質量％、Ｍｇ：１．５〜２．５質量％、Ｔｉ：０．０５〜０．３質量％、Ｎｉ：０．５〜２．０質量％、及びＺｒ：０．０５〜０．３質量％を含有し、残部が不可避不純物及びアルミニウムからなるアルミニウム合金の鋳塊を、４００〜５２０℃の温度で１〜２０時間保持する均質化処理と、
該均質化処理を行い得られる均質化処理材を、３００〜５００℃の温度で熱間加工する熱間加工工程と、
該熱間加工工程を行い得られる熱間加工材を、該熱間加工材の溶融開始温度より１０〜２０℃低い温度域で、０．５〜５時間保持する一段目の溶体化処理と、該一段目の溶体化処理温度より５〜１０℃高い温度域で、０．５〜５時間保持する二段目の溶体化処理と、を続けて行った後、水冷して焼入れする二段溶体化処理と、
該二段溶体化処理を行い得られる二段溶体化処理材を、１５０〜２２０℃の温度で、２〜３０時間保持する人工時効処理と、
を有することを特徴とするアルミニウム合金の製造方法である。
The manufacturing method of the aluminum alloy of the present invention is as follows: Cu: 2.0 to 3.5% by mass, Si: 0.1 to 0.5% by mass, Fe: 0.5 to 1.0% by mass, Mn: 0. 3 to 0.8% by mass, Mg: 1.5 to 2.5% by mass, Ti: 0.05 to 0.3% by mass, Ni: 0.5 to 2.0% by mass, and Zr: 0.05 A homogenization treatment of holding an ingot of an aluminum alloy containing ０．３0.3% by mass and the balance being inevitable impurities and aluminum at a temperature of 400 to 520 ° C. for 1 to 20 hours;
A hot working step of hot working the homogenized material obtained by performing the homogenizing process at a temperature of 300 to 500 ° C;
A first-stage solution treatment in which the hot-worked material obtained by performing the hot-working step is held for 0.5 to 5 hours in a temperature range lower by 10 to 20 ° C. than the melting start temperature of the hot-worked material; A second stage solution treatment in which the second stage solution treatment is performed in a temperature range higher by 5 to 10 ° C. than the first stage solution treatment temperature for 0.5 to 5 hours, followed by water cooling and quenching. Conversion processing,
An artificial aging treatment in which the two-step solution treatment material obtained by performing the two-step solution treatment is kept at a temperature of 150 to 220 ° C. for 2 to 30 hours;
It is a manufacturing method of the aluminum alloy characterized by having.
本発明のアルミニウム合金の製造方法では、先ず、所定の組成を有するアルミニウム合金を溶解し、ＤＣ鋳造により、所定の組成を有するアルミニウム合金からなるビレットを造塊する。ビレット中のＣｕ含有量は、２．０〜３．５質量％、好ましくは２．５〜３．３質量％であり、Ｓｉ含有量は、０．１〜０．５質量％、好ましくは０．２〜０．４質量％であり、Ｆｅ含有量は、０．５〜１．０質量％、好ましくは０．６〜０．９質量％であり、Ｍｎ含有量は、０．３〜０．８質量％、好ましくは０．４〜０．７質量％であり、Ｍｇ含有量は、１．５〜２．５質量％、好ましくは１．７〜２．１質量％であり、Ｔｉ含有量は、０．０５〜０．３質量％、好ましくは０．１〜０．２質量％であり、Ｎｉ含有量は、０．５〜２．０質量％、好ましくは０．８〜１．３質量％であり、Ｚｒ含有量は、０．０５〜０．３質量％、好ましくは０．１〜０．２質量％であり、必要に応じて、Ｓｃを含有する場合、Ｓｃ含有量は、０．０５〜０．３質量％、好ましくは０．１〜０．２質量％である。 In the method for producing an aluminum alloy of the present invention, first, an aluminum alloy having a predetermined composition is melted, and a billet made of an aluminum alloy having a predetermined composition is formed by DC casting. The Cu content in the billet is 2.0 to 3.5% by mass, preferably 2.5 to 3.3% by mass, and the Si content is 0.1 to 0.5% by mass, preferably 0%. 0.2 to 0.4 mass%, the Fe content is 0.5 to 1.0 mass%, preferably 0.6 to 0.9 mass%, and the Mn content is 0.3 to 0 mass%. 0.8% by mass, preferably 0.4 to 0.7% by mass, the Mg content is 1.5 to 2.5% by mass, preferably 1.7 to 2.1% by mass, and the Ti content is The amount is 0.05-0.3% by mass, preferably 0.1-0.2% by mass, and the Ni content is 0.5-2.0% by mass, preferably 0.8-1. 3% by mass, the Zr content is 0.05 to 0.3% by mass, preferably 0.1 to 0.2% by mass. If necessary, when Sc is contained, the Sc content is , 0.05- .3% by weight, preferably from 0.1 to 0.2 wt%.
本発明のアルミニウム合金の製造方法に係る均質化処理では、鋳造により得られるビレットを、４００〜５２０℃の温度で１〜２０時間保持することにより、均質化を行い、均質化処理材を得る。均質化温度が、４００℃未満だと、十分な均質化が行われず、また、５２０℃を超えると、偏在するミクロ偏析が共晶融解を起こすため、疲労強度が低くなる。均質化時間が、１時間未満だと、十分な均質化が行われず、また、２０時間を超えると、均質化処理のための熱処理炉の占有時間が長くなり過ぎるため、製造コストを増大させる。 In the homogenization treatment according to the method for producing an aluminum alloy of the present invention, the billet obtained by casting is kept at a temperature of 400 to 520 ° C. for 1 to 20 hours to perform homogenization to obtain a homogenized material. If the homogenization temperature is lower than 400 ° C., sufficient homogenization is not performed. If the homogenization temperature is higher than 520 ° C., unevenly distributed microsegregation causes eutectic melting, so that fatigue strength is reduced. If the homogenization time is less than 1 hour, sufficient homogenization will not be performed, and if it exceeds 20 hours, the occupation time of the heat treatment furnace for the homogenization treatment will be too long, and the production cost will increase.
本発明のアルミニウム合金の製造方法に係る熱間加工工程では、均質化処理材を、３００〜５００℃の温度で熱間加工することにより、熱間加工材を得る。熱間加工としては、押出加工、鍛造加工が好ましい。熱間加工工程では、１回以上熱間加工を行う。熱間加工を行わないと、鋳造組織のまま、ミクロ的な偏析が存在しているため、疲労強度が低くなる。熱間加工温度が３００℃未満だと、加工ひずみが材料内部に蓄積されるため、溶体化処理の際に結晶粒の粗大化が生じて、強度が低くなり、また、５００℃を超えると、加工変形中の加工発熱が加わり、部分的に共晶融解が発生して、疲労強度が低くなる。 In the hot working step according to the method for manufacturing an aluminum alloy of the present invention, a hot worked material is obtained by hot working the homogenized material at a temperature of 300 to 500 ° C. Extrusion and forging are preferred as hot working. In the hot working step, hot working is performed once or more. If hot working is not performed, fatigue strength is reduced because microscopic segregation is present in the cast structure. If the hot working temperature is lower than 300 ° C., since processing strain is accumulated inside the material, the crystal grains are coarsened during the solution treatment, and the strength is reduced. Heat generated during processing is added during processing, and eutectic melting occurs partially, resulting in low fatigue strength.
本発明のアルミニウム合金の製造方法に係る二段溶体化処理では、熱間加工材を、熱間加工材の溶融開始温度より１０〜２０℃低い温度域で、０．５〜５時間保持する一段目の溶体化処理と、一段目の溶体化処理温度より５〜１０℃高い温度域で、０．５〜５時間保持する二段目の溶体化処理とを、続けて行った後、水冷して焼入れし、二段溶体化処理材を得る。 In the two-step solution treatment according to the method for manufacturing an aluminum alloy according to the present invention, the first step is to hold the hot-worked material in a temperature range lower than the melting start temperature of the hot-worked material by 10 to 20 ° C for 0.5 to 5 hours. The solution heat treatment of the second stage and the second solution heat treatment of the first stage at a temperature higher by 5 to 10 ° C. than the temperature of the first solution heat treatment for 0.5 to 5 hours are continuously performed, followed by water cooling. To obtain a two-step solution treatment material.
一段目の溶体化処理では、熱間加工材の溶融開始温度より１０〜２０℃低い温度域で加熱することにより、熱間加工材の表面から内部にかけてミクロ偏析を熱的になくして均質化し、表層と内部の溶融開始温度差をなくすことで、二段目の溶体化処理を一段目の溶体化処理より高温で行うことが可能になる。溶体化処理の温度が高いほど、合金マトリックス中の過飽和固溶量が増大し、人工時効による微細析出物の析出量が多くなって、強度が高くなる。熱間加工材の溶融開始温度と、一段目の溶体化処理温度との差が、１０℃未満だと、ミクロ偏析が存在する場合には、共晶融解が生じ、靭性が低くなり、表面のふくれ発生の原因となり、また、熱間加工材の溶融開始温度と、一段目の溶体化処理温度との差が、２０℃を超えると、均質化が十分ではないために、二段目の溶体化処理において共晶融解が発生するおそれがある。また、一段目の溶体化処理時間が、０．５時間未満だと、均質化が十分ではないために、二段目の溶体化処理において共晶融解が発生するおそれがあり、また、一段目の溶体化処理時間が、５時間を超えると、熱処理炉の占有時間が長くなり過ぎるため、製造コストを増大させる。なお、一段目の溶体化処理において、熱間加工材の溶融開始温度より１０〜２０℃低い温度域で加熱するとは、例えば、熱間加工後の熱間加工材の溶融開始温度が５００℃であったとすると、一段目の溶体化処理では、４８０〜４９０℃の温度域で加熱するということを指す。 In the first-stage solution treatment, by heating in a temperature range of 10 to 20 ° C. lower than the melting start temperature of the hot-worked material, the micro-segregation is thermally eliminated from the surface to the inside of the hot-worked material and homogenized, Eliminating the difference in the melting start temperature between the surface layer and the inside allows the second-stage solution treatment to be performed at a higher temperature than the first-stage solution treatment. As the temperature of the solution treatment increases, the amount of supersaturated solid solution in the alloy matrix increases, the amount of fine precipitates precipitated by artificial aging increases, and the strength increases. If the difference between the melting start temperature of the hot-worked material and the first-stage solution treatment temperature is less than 10 ° C, if micro-segregation is present, eutectic melting occurs, toughness is reduced, and surface If the difference between the melting start temperature of the hot-worked material and the first-step solution treatment temperature exceeds 20 ° C., the homogenization is not sufficient. Eutectic melting may occur during the crystallization treatment. If the time of the first solution treatment is less than 0.5 hours, the homogenization is not sufficient, so that eutectic melting may occur in the second solution treatment. If the solution treatment time exceeds 5 hours, the occupation time of the heat treatment furnace becomes too long, and the production cost increases. In the first-stage solution treatment, heating in a temperature range lower than the melting start temperature of the hot-worked material by 10 to 20 ° C. means that, for example, the melting start temperature of the hot-worked material after hot working is 500 ° C. If so, in the first-stage solution treatment, it means that heating is performed in a temperature range of 480 to 490 ° C.
二段目の溶体化処理では、一段目の溶体化処理温度より５〜１０℃高い温度域で加熱することより、高い温度で溶体化処理を行うことになるので、合金マトリックス中の過飽和固溶量が増大し、人工時効による微細析出物の析出量が多くなって、強度が高くなる。二段目の溶体化処理温度と、一段目の溶融開始温度との差が、１０℃を超えると、部分的な再結晶組織の形成や共晶融解を招き、強度及びシャルピー衝撃値が低くなり、表面のふくれ発生の原因となり、また、二段目の溶体化処理温度と、一段目の溶体化処理温度との差が、５℃未満だと、合金マトリックス中のＣｕやＭｇの過飽和固溶量が少なくなるため、強度が高くならない。また、二段目の溶体化処理時間が、０．５時間未満だと、合金マトリックス中のＣｕやＭｇの過飽和固溶量が少なくなるため、強度が高くならず、また、二段目の溶体化処理時間が、５時間を超えると、熱処理炉の占有時間が長くなり過ぎるため、製造コストを増大させる。なお、二段目の溶体化処理において、一段目の溶体化処理温度より５〜１０℃高い温度域で加熱するとは、例えば、一段目の溶体化処理で、４８５℃で加熱したとすると、二段目の溶体化処理では、４９０〜４９５℃の温度域で加熱することを指す。 In the second-stage solution treatment, since the solution treatment is performed at a higher temperature by heating in a temperature range 5 to 10 ° C. higher than the first-stage solution treatment temperature, the supersaturated solid solution in the alloy matrix is increased. As a result, the amount of fine precipitates due to artificial aging increases, and the strength increases. If the difference between the solution heat treatment temperature in the second step and the melting start temperature in the first step exceeds 10 ° C., partial recrystallization structure is formed and eutectic melting is caused, and strength and Charpy impact value become low. If the difference between the solution heat treatment temperature in the second step and the solution heat treatment temperature in the first step is less than 5 ° C., supersaturated solid solution of Cu or Mg in the alloy matrix may occur. The strength is not increased because the amount is reduced. If the second-stage solution treatment time is less than 0.5 hours, the amount of supersaturated solid solution of Cu and Mg in the alloy matrix decreases, so that the strength does not increase and the second-stage solution If the heat treatment time exceeds 5 hours, the occupation time of the heat treatment furnace becomes too long, and the production cost increases. In addition, in the second-stage solution treatment, heating in a temperature range higher by 5 to 10 ° C. than the first-stage solution treatment temperature means that, for example, in the first-stage solution treatment, heating is performed at 485 ° C. In the solution heat treatment at the stage, heating is performed in a temperature range of 490 to 495 ° C.
本発明のアルミニウム合金の製造方法に係る人工時効処理では、二段溶体化処理材を、１５０〜２２０℃の温度で、２〜３０時間保持する。人工時効処理温度が、１５０℃未満だと、析出量が少ないため、強度が低くなり、また、２２０℃を超えると、粗大な析出物が生じるため、強度が低くなる。また、人工時効処理温度が、２時間未満だと、析出量が少ないため、強度が低くなり、また、３０時間を超えると、熱処理炉の占有時間が長くなり過ぎるため、製造コストを増大させる。 In the artificial aging treatment according to the method for producing an aluminum alloy of the present invention, the two-step solution treatment material is kept at a temperature of 150 to 220 ° C for 2 to 30 hours. If the artificial aging treatment temperature is lower than 150 ° C., the strength decreases because the amount of precipitation is small, and if it exceeds 220 ° C., coarse precipitates are generated and the strength decreases. Further, if the artificial aging treatment temperature is less than 2 hours, the strength is low because the amount of precipitation is small, and if it exceeds 30 hours, the occupation time of the heat treatment furnace is too long, and the production cost is increased.
本発明のアルミニウム合金の製造方法を行うことにより得られるアルミニウム合金は、塑性加工方向に平行な断面の結晶粒の平均アスペクト比が５以上の繊維組織である。そのため、本発明のアルミニウム合金の製造方法を行うことにより得られるアルミニウム合金は、２５℃での引張強さ（Ａ）が４８０ＭＰａ以上であり、且つ、２５℃での引張強さ（Ａ）と、２００℃の温度で１０時間暴露保持した後、２５℃で測定したときの引張強さ（Ｂ）との差（Ａ−Ｂ）が５０ＭＰａ以下である。つまり、本発明のアルミニウム合金の製造方法を行うことにより得られるアルミニウム合金は、強度が高く且つ耐熱性が高い。 The aluminum alloy obtained by performing the method for producing an aluminum alloy of the present invention has a fiber structure in which the average aspect ratio of crystal grains having a cross section parallel to the plastic working direction is 5 or more. Therefore, the aluminum alloy obtained by performing the method for producing an aluminum alloy of the present invention has a tensile strength (A) at 25 ° C. of 480 MPa or more, and a tensile strength (A) at 25 ° C. After exposure and holding at a temperature of 200 ° C. for 10 hours, the difference (A−B) from the tensile strength (B) measured at 25 ° C. is 50 MPa or less. That is, an aluminum alloy obtained by performing the method for manufacturing an aluminum alloy of the present invention has high strength and high heat resistance.
以下に、実施例を示して、本発明を具体的に説明するが、本発明は、以下に示す実施例に限定されるものではない。 Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the examples described below.
（実施例１及び比較例１）
ＤＣ鋳造によって得た表１（実施例）及び表２（比較例）に示す組成のアルミニウム合金のビレット（直径９０ｍｍ）を、４７０℃で２０時間均質化処理した。なお、表１及び表２では、含有量は質量％であり、残部はアルミニウムである。次いで、４００℃で熱間押出し、直径１５ｍｍの丸棒材形状の熱間押出材を得た。次いで、熱間押出材に、一段目の溶体化処理として、５２０℃の温度で２時間保持し、続けて、二段目の溶体化処理として、５２７℃の温度で２時間保持した後、水冷却による焼入れを行った。次いで、１９０℃で２０時間の人工時効処理を行い、Ｔ６調質のアルミニウム合金を得た。
次いで、得られたアルミニウム合金の評価を行った。その結果を表３に示す。
(Example 1 and Comparative Example 1)
A billet (diameter: 90 mm) of an aluminum alloy having a composition shown in Table 1 (Example) and Table 2 (Comparative Example) obtained by DC casting was homogenized at 470 ° C. for 20 hours. In Tables 1 and 2, the content is% by mass, and the balance is aluminum. Subsequently, hot extrusion was performed at 400 ° C. to obtain a round extruded material having a diameter of 15 mm. Next, the hot extruded material is held at a temperature of 520 ° C. for 2 hours as a first-stage solution treatment, and is then held at a temperature of 527 ° C. for 2 hours as a second-stage solution treatment. Quenching by cooling was performed. Next, artificial aging treatment was performed at 190 ° C. for 20 hours to obtain a T6 tempered aluminum alloy.
Next, the obtained aluminum alloy was evaluated. Table 3 shows the results.
＜共晶融解開始温度の測定＞
熱間押出材を示差走査熱量計で測定し、共晶融解開始温度を求めた。
<Measurement of eutectic melting onset temperature>
The hot extruded material was measured with a differential scanning calorimeter to determine the eutectic melting onset temperature.
＜引張強さの測定＞
ＪＩＳ Ｚ ２２４１に準拠して、引張強さを測定した。
試験試料は、人工時効処理を行い得られたアルミニウム合金（試験試料１）と、人工時効処理を行い得られたアルミニウム合金を、１００℃／時間の昇温速度で、２００℃まで加熱し、次いで、２００℃で１０時間保持し、次いで、空冷して、室温程度まで冷却したアルミニウム合金（試験試料２）とした。
<Measurement of tensile strength>
The tensile strength was measured according to JIS Z 2241.
The test sample was prepared by heating the aluminum alloy obtained by performing the artificial aging treatment (test sample 1) and the aluminum alloy obtained by performing the artificial aging treatment to 200 ° C. at a heating rate of 100 ° C./hour. , 200 ° C. for 10 hours, and then air-cooled to obtain an aluminum alloy (test sample 2) cooled to about room temperature.
＜結晶粒の平均アスペクト比の測定＞
アルミニウム合金の塑性加工方向に平行な断面を、電解エッチングにより結晶粒を現出させ、材料組織を偏光光学顕微鏡により、倍率２５倍で撮影した。撮影写真上に観察される結晶粒から、任意に１０個選択し、個々の結晶粒について、「（塑性加工方向の長さ）／（塑性加工方向に直行する方向の長さ）」の式により、アスペクト比を計算した。任意に選択した１０個の結晶粒のアスペクト比を平均し、平均アスペクト比を求めた。なお、アスペクト比が十分に大きく、全ての結晶粒の塑性加工方向の長さが撮影視野を超え、アスペクト比が５以上と判断できる場合は、平均アスペクト比は５以上とした。
<Measurement of average aspect ratio of crystal grains>
A cross section parallel to the plastic working direction of the aluminum alloy was exposed to crystal grains by electrolytic etching, and the material structure was photographed with a polarizing optical microscope at a magnification of 25 times. From the crystal grains observed on the photographed photograph, arbitrarily select ten crystal grains, and for each crystal grain, use the formula of (length in the plastic working direction) / (length in the direction perpendicular to the plastic working direction). And the aspect ratio was calculated. The aspect ratios of 10 crystal grains arbitrarily selected were averaged to obtain an average aspect ratio. The average aspect ratio was set to 5 or more when the aspect ratio was sufficiently large, the length of all the crystal grains in the plastic working direction exceeded the visual field of view, and the aspect ratio could be determined to be 5 or more.
比較例Ｎｏ．２１〜３７は、本発明の範囲外であるため、材料の成形が良好ではないか、引張強さが良好なものが得られなかった。
比較例Ｎｏ．２１は、Ｃｕ含有量が２．０質量％未満のため、強度が低かった。
比較例Ｎｏ．２２は、Ｃｕ含有量が３．５質量％を超えているため、共晶融解開始温度が低くなり、再結晶が生じ、材料の引張強さが低かった。
比較例Ｎｏ．２３は、Ｓｉ含有量が０．１質量％未満のため、再結晶組織が形成され、引張強さと結晶粒の平均アスペクト比が低かった。
比較例Ｎｏ．２４は、Ｓｉ含有量が０．５質量％を超えているため、粗大化合物が形成され、２００℃で１０時間曝露保持後の強度が低下した。
比較例Ｎｏ．２５は、Ｆｅ含有量が０．１質量％未満のため、強度が低かった。
比較例Ｎｏ．２６は、Ｆｅ含有量が１．０質量％を超えているため、粗大化合物を形成し、２００℃で１０時間曝露保持後の強度が低下した。
比較例Ｎｏ．２７は、Ｍｎ含有量が０．３質量％未満のため、再結晶組織が形成され、引張強さと結晶粒の平均アスペクト比が低くなった。
比較例Ｎｏ．２８は、Ｍｎ含有量が０．８質量％を超えているため、粗大化合物を形成し、２００℃で１０時間曝露保持後の強度が低下した。
比較例Ｎｏ．２９は、Ｍｇ含有量が１．５質量％未満のため、強度が低かった。
比較例Ｎｏ．３０は、Ｍｇ含有量が２．５質量％を超えているため、成形加工性が悪く、押出加工時に割れが生じた。
比較例Ｎｏ．３１は、Ｔｉ含有量が０．０５質量％未満のため、再結晶組織が形成され、引張強さと結晶粒の平均アスペクト比が低くなった。
比較例Ｎｏ．３２は、Ｔｉ含有量が０．３質量％を超えているため、鋳塊に粗大な化合物が生じ、押出加工時に割れが生じた。
比較例Ｎｏ．３３は、Ｎｉ含有量が０．５質量％未満のため、高温強度が低かった。
比較例Ｎｏ．３４は、Ｎｉ含有量が２．０質量％を超えているため、Ｎｉ系金属間化合物がマトリックス中に分散し、高温強度が低かった。
比較例Ｎｏ．３５は、Ｚｒ含有量が０．０５質量％未満のため、再結晶組織が形成され、引張強さと結晶粒の平均アスペクト比が低かった。
比較例Ｎｏ．３６は、Ｚｒ含有量が０．３質量％を超えているため、鋳塊に粗大な化合物が生じ、押出加工時に割れが生じた。
比較例Ｎｏ．３７は、Ｓｃ含有量が０．３質量％を超えているため、微細に析出せずに粗大化合物を形成したため、強度が低くなった。
それに対し、実施例Ｎｏ．１〜２０は、本発明の範囲内であるため、塑性加工方向に平行な断面の結晶粒の平均アスペクト比が５以上の繊維組織で、２５℃で測定した引張強さが４５０ＭＰａ以上であり、且つ、２５℃での引張強さ（Ａ）と、２５℃で測定した引張強さと、２００℃の温度で１０時間暴露保持した後、２５℃で測定した引張強さとの差が、５０ＭＰａ以下であった。
Comparative Example No. Since Nos. 21 to 37 were out of the range of the present invention, the molding of the material was not good or a material having good tensile strength was not obtained.
Comparative Example No. Sample No. 21 had low strength because the Cu content was less than 2.0% by mass.
Comparative Example No. In No. 22, since the Cu content exceeded 3.5% by mass, the eutectic melting onset temperature was low, recrystallization occurred, and the tensile strength of the material was low.
Comparative Example No. In No. 23, since the Si content was less than 0.1% by mass, a recrystallized structure was formed, and the tensile strength and the average aspect ratio of crystal grains were low.
Comparative Example No. In No. 24, since the Si content exceeded 0.5% by mass, a coarse compound was formed, and the strength after exposure and holding at 200 ° C. for 10 hours was reduced.
Comparative Example No. Sample No. 25 had low strength because the Fe content was less than 0.1% by mass.
Comparative Example No. In No. 26, since the Fe content exceeded 1.0% by mass, a coarse compound was formed, and the strength after exposure and holding at 200 ° C. for 10 hours was reduced.
Comparative Example No. In No. 27, since the Mn content was less than 0.3% by mass, a recrystallized structure was formed, and the tensile strength and the average aspect ratio of crystal grains were low.
Comparative Example No. In No. 28, since the Mn content exceeded 0.8% by mass, a coarse compound was formed, and the strength after exposure and holding at 200 ° C. for 10 hours was reduced.
Comparative Example No. No. 29 had a low strength because the Mg content was less than 1.5% by mass.
Comparative Example No. In No. 30, since the Mg content exceeded 2.5% by mass, the moldability was poor, and cracks occurred during extrusion.
Comparative Example No. In No. 31, since the Ti content was less than 0.05% by mass, a recrystallized structure was formed, and the tensile strength and the average aspect ratio of the crystal grains were low.
Comparative Example No. In No. 32, since the Ti content exceeded 0.3% by mass, a coarse compound was formed in the ingot, and cracks occurred during extrusion.
Comparative Example No. No. 33 had a low high-temperature strength because the Ni content was less than 0.5% by mass.
Comparative Example No. In No. 34, since the Ni content exceeded 2.0% by mass, the Ni-based intermetallic compound was dispersed in the matrix, and the high-temperature strength was low.
Comparative Example No. In No. 35, since the Zr content was less than 0.05% by mass, a recrystallized structure was formed, and the tensile strength and the average aspect ratio of crystal grains were low.
Comparative Example No. In No. 36, since the Zr content exceeded 0.3% by mass, a coarse compound was formed in the ingot, and cracks occurred during extrusion.
Comparative Example No. In No. 37, the Sc content was more than 0.3% by mass, so that a coarse compound was formed without precipitating finely, so that the strength was low.
On the other hand, in Example No. 1 to 20 are within the scope of the present invention, the average aspect ratio of the crystal grains of the cross section parallel to the plastic working direction is a fiber structure of 5 or more, the tensile strength measured at 25 ° C. is 450 MPa or more, Further, the difference between the tensile strength at 25 ° C. (A), the tensile strength measured at 25 ° C., and the exposure strength held at 200 ° C. for 10 hours, and then the tensile strength measured at 25 ° C. is 50 MPa or less. there were.
（実施例２及び比較例２）
ＤＣ鋳造によって得た表４に示す組成のアルミニウム合金のビレット（直径９０ｍｍ）を、４７０℃で２０時間均質化処理した。なお、表４では、含有量は質量％であり、残部はアルミニウムである。次いで、４００℃で熱間押出し、直径１５ｍｍの丸棒材形状の熱間押出材を得た。次いで、熱間押出材に、表５又は表６に示す条件で、一段目の溶体化処理を行い、続けて、二段目の溶体化処理を行った後、水冷却による焼入れを行った。次いで、１９０℃で２０時間の人工時効処理を行い、Ｔ６調質のアルミニウム合金を得た。
次いで、得られたアルミニウム合金の評価を行った。その結果を表７に示す。
(Example 2 and Comparative Example 2)
A billet (diameter: 90 mm) of an aluminum alloy having a composition shown in Table 4 obtained by DC casting was homogenized at 470 ° C. for 20 hours. In Table 4, the content is% by mass, and the balance is aluminum. Subsequently, hot extrusion was performed at 400 ° C. to obtain a round extruded material having a diameter of 15 mm. Next, the hot extruded material was subjected to a first-stage solution treatment under the conditions shown in Table 5 or Table 6, followed by a second-stage solution treatment, followed by quenching by water cooling. Next, artificial aging treatment was performed at 190 ° C. for 20 hours to obtain a T6 tempered aluminum alloy.
Next, the obtained aluminum alloy was evaluated. Table 7 shows the results.
比較例Ｎｏ．４２〜４５は、本発明の範囲外であるため、材料の成形が良好ではないか、引張強さが良好なものが得られなかった。
比較例Ｎｏ．４２と比較例Ｎｏ．４４は、熱間加工材の共晶融解開始温度と、一段目の溶体化処理温度との差が、２０℃を超え、二段目の溶体化処理温度と、一段目の溶体化処理温度との差が、５℃未満であるため、溶体化処理による過飽和固溶量が少なく、人工時効処理で析出強化が不十分であったため、材料の強度向上効果が得られなかった。
比較例Ｎｏ．４３と比較例Ｎｏ．４５は、熱間加工材の共晶融解開始温度と、一段目の溶体化処理温度との差が、１０℃未満であり、二段目の溶体化処理温度と、一段目の溶体化処理温度との差が、１０℃を超えているため、材料に再結晶が生じ、アスペクト比が低下した結果、２５℃の強度及び２００℃の温度で１０時間曝露保持後の強度が低下した。
それに対し、実施例Ｎｏ．３８〜４１は、本発明の範囲内であるため、塑性加工方向に平行な断面の結晶粒の平均アスペクト比が５以上の繊維組織で、２５℃で測定した引張強さが４５０ＭＰａ以上であり、且つ、２５℃での引張強さ（Ａ）と、２５℃で測定した引張強さと、２００℃の温度で１０時間暴露保持した後、２５℃で測定した引張強さとの差が、５０ＭＰａ以下であった。
Comparative Example No. Samples Nos. 42 to 45 were out of the range of the present invention, so that the molding of the material was not good or a material having a good tensile strength was not obtained.
Comparative Example No. 42 and Comparative Example No. 42. 44, the difference between the eutectic melting start temperature of the hot-worked material and the first-stage solution treatment temperature exceeds 20 ° C., and the second-stage solution treatment temperature and the first-stage solution treatment temperature Is less than 5 ° C., the amount of supersaturated solid solution by the solution treatment is small, and the precipitation strengthening by the artificial aging treatment is insufficient, so that the effect of improving the strength of the material cannot be obtained.
Comparative Example No. No. 43 and Comparative Example No. 43. 45, the difference between the eutectic melting start temperature of the hot-worked material and the first-stage solution treatment temperature is less than 10 ° C., and the second-stage solution treatment temperature and the first-stage solution treatment temperature As a result, the material was recrystallized and the aspect ratio was lowered. As a result, the strength after exposure and holding at a temperature of 25 ° C. and a temperature of 200 ° C. for 10 hours was lowered.
On the other hand, in Example No. Since 38 to 41 are within the range of the present invention, the fiber structure in which the average aspect ratio of the crystal grains in the cross section parallel to the plastic working direction is 5 or more, the tensile strength measured at 25 ° C is 450 MPa or more, Further, the difference between the tensile strength at 25 ° C. (A), the tensile strength measured at 25 ° C., and the exposure strength held at 200 ° C. for 10 hours, and then the tensile strength measured at 25 ° C. is 50 MPa or less. there were.
Claims (4)
該均質化処理を行い得られる均質化処理材を、３００〜５００℃の温度で熱間加工する熱間加工工程と、
該熱間加工工程を行い得られる熱間加工材を、該熱間加工材の溶融開始温度より１０〜２０℃低い温度域で、０．５〜５時間保持する一段目の溶体化処理と、該一段目の溶体化処理温度より５〜１０℃高い温度域で、０．５〜５時間保持する二段目の溶体化処理と、を続けて行った後、水冷して焼入れする二段溶体化処理と、
該二段溶体化処理を行い得られる二段溶体化処理材を、１５０〜２２０℃の温度で、２〜３０時間保持する人工時効処理と、
を有することを特徴とするアルミニウム合金の製造方法。 Cu: 2.0 to 3.5% by mass, Si: 0.1 to 0.5% by mass, Fe: 0.5 to 1.0% by mass, Mn: 0.3 to 0.8% by mass, Mg: 1.5 to 2.5% by mass, Ti: 0.05 to 0.3% by mass, Ni: 0.5 to 2.0% by mass, and Zr: 0.05 to 0.3% by mass, The remaining part is an ingot of an aluminum alloy consisting of unavoidable impurities and aluminum, a homogenization treatment of holding at a temperature of 400 to 520 ° C. for 1 to 20 hours,
A hot working step of hot working the homogenized material obtained by performing the homogenizing process at a temperature of 300 to 500 ° C;
A first-stage solution treatment in which the hot-worked material obtained by performing the hot-working step is held for 0.5 to 5 hours in a temperature range lower by 10 to 20 ° C. than the melting start temperature of the hot-worked material; A second stage solution treatment in which the second stage solution treatment is performed in a temperature range higher by 5 to 10 ° C. than the first stage solution treatment temperature for 0.5 to 5 hours, followed by water cooling and quenching. Conversion processing,
An artificial aging treatment in which the two-step solution treatment material obtained by performing the two-step solution treatment is kept at a temperature of 150 to 220 ° C. for 2 to 30 hours;
A method for producing an aluminum alloy, comprising:
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| JP2017043802A (en) * | 2015-08-25 | 2017-03-02 | 株式会社Uacj | Aluminum alloy extrusion material and manufacturing method therefor |
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| JP2010018854A (en) * | 2008-07-11 | 2010-01-28 | Sumitomo Light Metal Ind Ltd | Lightweight and high strength aluminum alloy excellent in heat resistance |
| JP2017043802A (en) * | 2015-08-25 | 2017-03-02 | 株式会社Uacj | Aluminum alloy extrusion material and manufacturing method therefor |
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