JP2011144396A5

JP2011144396A5 -

Info

Publication number: JP2011144396A5
Application number: JP2010003996A
Authority: JP
Filing date: 2010-01-12
Publication date: 2012-11-08
Anticipated expiration: 2030-01-12

Description

本発明に係るＡｌ−Ｚｎ−Ｍｇ系アルミニウム合金押出材は、Ｍｇの質量％を［Ｍｇ］、Ｚｎの質量％を［Ｚｎ］としたとき、［Ｍｇ］と［Ｚｎ］が下記（１）〜（３）式を満たし、
５．０≦［Ｚｎ］≦７．０・・・（１）
［Ｚｎ］／５．３８＋０．１５≦［Ｍｇ］≦［Ｚｎ］／５．３８＋０．７・・・（２）
［Ｚｎ］＋４．７［Ｍｇ］≦１４・・・（３）
さらに、Ｃｕ：０．１〜０．６質量％，Ａｇ：０．０１〜０．１５質量％の１種又は２種と、Ｔｉ：０．００５〜０．０５質量％と、Ｍｎ：０．１〜０．３質量％，Ｃｒ：０．０５〜０．２質量％，Ｚｒ：０．０５〜０．２質量％の１種又は２種以上を含み、残部Ａｌ及び不可避不純物からなる。
ＭｇＺｎ_２の化学量論比（質量比）は、［Ｍｇ］：［Ｚｎ］が１：５．３８であるから、上記（２）式は、［Ｍｇ］がＭｇＺｎ_２の化学量論比より０．１５質量％以上過剰で、かつ過剰［Ｍｇ］が０．７質量％以下であることを意味する。 In the Al—Zn—Mg-based aluminum alloy extruded material according to the present invention, [Mg] and [Zn] are expressed by the following (1) to [Mg] when the Mg mass% is [Mg] and the Zn mass% is [Zn]. (3) is satisfied,
5.0 ≦ [Zn] ≦ 7.0 (1)
[Zn] /5.38 + 0.15 ≦ [ Mg] ≦ [Zn] /5.38+0.7 ··· (2)
[Zn] +4.7 [Mg] ≦ 14 (3)
Furthermore, Cu: 0.1-0.6 mass%, Ag: 0.01-0.15 mass% 1 type or 2 types, Ti: 0.005-0.05 mass%, Mn: 0.0. 1-0.3 mass%, Cr: 0.05-0.2 mass%, Zr: 0.05-0.2 mass% of 1 type (s) or 2 or more types are comprised, and it consists of remainder Al and an unavoidable impurity.
Since the stoichiometric ratio (mass ratio) of MgZn ₂ is [Mg]: [Zn] is 1: 5.38, the above formula (2) indicates that [Mg] is 0 from the stoichiometric ratio of MgZn _2. .15% by mass or more and excess [Mg] is 0.7% by mass or less.

Ｍｇ；
ＭｇはＺｎとともにＭｇＺｎ_２を形成してＡｌ−Ｚｎ−Ｍｇ系合金の強度を向上させる。その含有量は、Ｚｎ含有量との関係で、前記（２），（３）式のとおりに制限される。
Ｍｇ含有量がＭｇＺｎ _２の化学量論比（［Ｚｎ］／５．３８）以下の領域ではＭｇＺｎ_２量が減少して強度が不足する。Ｍｇ含有量が前記（２）式の下限値以上の領域（ＭｇＺｎ_２の化学量論比＋０．１５質量％以上の過剰Ｍｇ領域）になると、過剰Ｍｇが高強度化に寄与するため、ＭｇＺｎ_２量を抑えたうえで高強度化が可能となる。しかし、過剰Ｍｇ量が０．７質量％を超えると押出性が低下し、ダイクエンチ空冷では高強度（対Ｔ６材比）が出ない。また、生産性が低下し、薄肉成形も困難になる。望ましくは過剰Ｍｇ量は０．６質量％以下である。
また、Ｚｎ及びＭｇ含有量が前記（３）式の規定を超えると、粒界析出物が微細かつ連続的に形成され、耐ＳＣＣ性が低下する。 Mg;
Mg forms MgZn ₂ together with Zn to improve the strength of the Al—Zn—Mg alloy. The content is limited as shown in the above formulas (2) and (3) in relation to the Zn content.
In a region where the Mg content is less than the stoichiometric ratio of MgZn ₂ ([Zn] /5.38), the amount of MgZn ₂ decreases and the strength is insufficient. When Mg content is the (2) the lower limit value or more regions (stoichiometric ratio +0.15 wt% or more excess Mg region of MgZn ₂₎ of, for excess Mg contributes to higher strength, MgZn ₂ It is possible to increase the strength while suppressing the amount. However, when the excess Mg amount exceeds 0.7% by mass, the extrudability decreases, and die quench air cooling does not provide high strength (compared to T6 material). In addition, productivity is reduced and thin wall molding becomes difficult. Desirably, the excess Mg amount is 0.6% by mass or less.
Moreover, when Zn and Mg content exceeds the prescription | regulation of said (3) Formula, a grain-boundary precipitate will be formed finely and continuously, and SCC resistance will fall.

図１は、本発明に係るＡｌ−Ｚｎ−Ｍｇ系合金のＺｎ及びＭｇ量の範囲を図示したものである。図中のプロット○は後述する表１のＮｏ．１〜１２、プロット●は同じく表１のＮｏ．１３〜１８である。［Ｚｎ］＝５．０、［Ｚｎ］＝７．０、［Ｍｇ］＝［Ｚｎ］／５．３８＋０．１５、［Ｍｇ］＝［Ｚｎ］／５．３８＋０．７、及び［Ｚｎ］＋４．７［Ｍｇ］＝１４で囲まれた五角形の領域が、本発明の規定範囲である。ただし、先に述べたように、耐ＳＣＣ性を重要視する観点からは、［Ｚｎ］≦６．３の低Ｚｎ領域が望ましく、［Ｚｎ］＞６．３の高Ｚｎ領域では、Ｃｕ及びＡｇの両方を添加して耐ＳＣＣ性を改善することが望ましい。 FIG. 1 illustrates the range of Zn and Mg content of an Al—Zn—Mg alloy according to the present invention. Plot ◯ in the figure indicates No. in Table 1 described later. 1 to 12 and plot ● are No. 1 in Table 1 . 13-18. [Zn] = 5.0, [Zn] = 7.0, [Mg] = [Zn] /5.38+0.15 , [Mg] = [Zn] /5.38+0.7, and [Zn] +4 A pentagonal region surrounded by .7 [Mg] = 14 is the specified range of the present invention. However, as described above, from the viewpoint of placing importance on SCC resistance, a low Zn region of [Zn] ≦ 6.3 is desirable, and in a high Zn region of [Zn]> 6.3, Cu and Ag It is desirable to add both of these to improve the SCC resistance.

表２に示すように、Ｎｏ．１〜１２(このうち本発明の規定範囲内の組成を有するものはＮｏ．１，２，５〜８，１１，１２）は、耐力及び伸びが大きく、同時に押出性と耐ＳＣＣ性にも優れている。Ｎｏ．３はＺｎ量が６．３質量％を超えているが、ＣｕとＡｇの両方が添加されたことにより耐ＳＣＣ性が優れる。Ｎｏ．１０はＺｎ量が６．３質量％を超え、Ａｇの添加がないことにより、他の実施例に比べて耐ＳＣＣ性がやや劣る。Ｎｏ．１１はＣｕの添加がない（０．０１％以下）が、Ａｇが添加されているため、耐ＳＣＣ性が優れる。 As shown in Table 2, no . Nos. 1 to 12 (among those having compositions within the specified range of the present invention, Nos. 1, 2, 5 to 8, 11, and 12) have large proof stress and elongation, and at the same time, excellent extrudability and SCC resistance. ing. No. No. 3 has a Zn content exceeding 6.3% by mass, but is excellent in SCC resistance due to the addition of both Cu and Ag. No. No. 10 has a Zn content exceeding 6.3% by mass and no addition of Ag, so that the SCC resistance is slightly inferior to other examples. No. 11 has no addition of Cu (0.01% or less), but has excellent SCC resistance because Ag is added.

Claims

When the mass% of Mg is [Mg] and the mass% of Zn is [Zn], [Mg] and [Zn] satisfy the following three formulas,
5.0 ≦ [Zn] ≦ 7.0
[Zn] /5.38 + 0.15 ≦ [ Mg] ≦ [Zn] /5.38+0.7
[Zn] +4.7 [Mg] ≦ 14
Furthermore, Cu: 0.1-0.6 mass%, Ag: 0.01-0.15 mass% 1 type or 2 types, Ti: 0.005-0.05 mass%, Mn: 0.0. 1 to 0.3% by mass, Cr: 0.05 to 0.2% by mass, Zr: 0.05 to 0.2% by mass, including one or more, and the balance consisting of Al and inevitable impurities High strength aluminum alloy extruded material with excellent stress corrosion cracking resistance.