US3717512A - Aluminum base alloys - Google Patents

Aluminum base alloys Download PDF

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Publication number
US3717512A
US3717512A US00193458A US3717512DA US3717512A US 3717512 A US3717512 A US 3717512A US 00193458 A US00193458 A US 00193458A US 3717512D A US3717512D A US 3717512DA US 3717512 A US3717512 A US 3717512A
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percent
alloy
zirconium
chromium
manganese
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US00193458A
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P Sperry
D Gullotti
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Olin Corp
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Olin Corp
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium

Definitions

  • ABSTRACT The disclosure teaches improved aluminum base alloys containing silicon, magnesium, chromium and zirconium.
  • the alloys have a combination of high strength and high impact properties.
  • the present invention relates to improved aluminum base alloys containing silicon and magnesium, wherein said alloy is a hot worked alloy and has high strength and high impact properties.
  • Hot worked aluminum base alloys containing magnesium and silicon find wide application in a wide variety of uses, for example, they may be readily used as extrusions, forgings or rolled products.
  • the improved alloy of the present invention consists essentially of silicon from 0.3 to 1.3 percent, magnesium from 0.3 to 1.5 percent, chromium from 0.03 to 0.40 percent, and zirconium from 0.03 to 0.20 percent, balance essentially aluminum, wherein substantially all grains are fibrous and grossly elongated, with a length to thickness ratio as extruded of at least to l, and preferably 100 to 1.
  • the alloy of the present invention also contains manganese in an amount from 0.03 to 0.40 percent, with the total chromium plus zirconium plus manganese content being preferably from 0.2 to 0.35 percent.
  • the improved alloy of the present invention is a hot worked product and has a surprising combination of high strength and high impact properties.
  • the microstructure is a substantially unrecrystallized grain structure, and, significantly, substantially all grains are fibrous and grossly elongated, with a length to thickness ratio as extruded of at least 10 to l.
  • the elongated grains contain a plurality of subgrains which are visible under high magnification.
  • the chromium and zirconium additions, and manganese when present are at least partly present in a uniform dispersion precipitated throughout the matrix. It is particularly surprising in accordance with the present invention that the alloy of the present invention achieves such excellent properties.
  • the improved alloy of the present invention is preferably processed in accordance with the following procedure: hot working the alloys at a finishing temperature in excess of 850F; water quenching the alloys down to a temperature of 350F or below at a cooling rate of from 1,000 to l0,000F per minute; and thermally artificially aging the alloys at a temperature from 0 200 to 410F for from 15 minutes to 24 hours.
  • the alloys of the present invention are characterized by a surprising combination of high strength and high impact toughness.
  • the minimum properties obtained in accordance with the foregoing process are as follows: tensile strength at least 38,000 psi; yield strength at 0.2 percent offset at least 35,000 psi and elongation at least 8 percent.
  • the minimum impact toughness of the alloys of the present invention is for a Va inch thick specimen, the Charpy V-Notch impact test yields at least 15 foot pounds. One would obtain at least 20 foot pounds for a 0.394 inch thick specimen, and typically 30 to 40 foot pounds.
  • the alloy of the present invention has numerous other highly desirable characteristics, for example, it is easily extruded and has good corrosion resistance.
  • the alloy of the present invention contains from 0.3 to 1.3 percent silicon and preferably from 0.4 to 0.9 percent silicon. Silicon in the preferred range has been found to give particularly advantageous results.
  • the alloy of the present invention contains magnesium in an amount from 0.3 to 1.5 percent and preferably from 0.4 to 1.0 percent.
  • the chromium content may vary from 0.03 to 0.40 percent and preferably from 0.05 to 0.35 percent.
  • the zirconium may vary from 0.03 to 0.20 percent and preferably from 0.05 to 0.15 percent.
  • manganese in an amount from 0.03 to 0.4 percent and preferably in an amount from 0.05 to 0.3 percent.
  • the present invention contemplates conventional impurities common for alloys of this type. This is important since it indicates that the improved properties of the alloys of the present invention are obtainable with normal commercial purity materials.
  • normal impurities include 0.60 percent maximum iron; 0.30 percent maximum copper, 0.50 percent maximum zinc; up to 0.008 percent boron; 0.10 percent maximum each of other elements the total of which is a maximum of 0.50 percent.
  • the microstructure of the alloys of the present invention is particularly significant in obtaining the surprisingly improved properties of the alloys of the present invention.
  • Substantially all grains are fibrous and grossly elongated, with a length to thickness ratio as extruded of at least to 1.
  • the upper specimen represents an alloy of the present invention, showing an unrecrystallized, fibrous grain structure, with grossly elongated grains.
  • the impact strength of this material was 55.8 foot pounds, and the material did not completely fracture.
  • the material on the bottom shows a completely recrystallized grain structure and had a Charpy impact strength of 10.8 foot pounds.
  • the grossly elongated grains contain a plurality of fine, substantially uniform subgrains or polygonized grain structure within each fibrous grain. These are visible under high magnification. Also, the precipitates formed by chromium, zirconium and manganese are favorably dispersed throughout the matrix. Thus, it can be seen that the alloys of the present invention consistently achieve high impact toughness together with other good physical characteristics due to their composition together with a highly advantageous microstructure.
  • the manner of melting and casting the alloy is not especially critical and conventional methods of melting and casting may be conveniently employed. It is desirable to uniformly distribute the silicon and magnesium throughout the matrix of the alloy before the process of the present invention is performed, such as by a homogenization heat treatment subsequent to the casting operation. Before or during hot working some high temperature precipitate should be formed due to Cr, Zr and Mn, as this is the mechanism by which recrystallization is inhibited. However, this can be accomplished by reheating for hot working as well as by homogenization.
  • finishing temperature it is meant the final temperature at which significant deformation is obtained in the but working operation.
  • die exit temperature should be in excess of 850F. It is preferable that the actual temperature be high enough to dissolve substantially all Mg and Si which is available for maximum strengthening.
  • the material should be rapidly quenched to a temperature of at least 350F at a cooling rate of l,000 to l0,000F per minute.
  • the rapid quenching is normally obtained by plunging the material in water or by passing the material through a water spray quench.
  • the material may then be cold worked up to 5 percent, e.g., rolling, stretching, etc.
  • the material should be then artificially aged at a temperature of 200 to 4l0F for minutes to 24 hours.
  • the alloys of the present invention are quench sensitive. It is a particularly surprising finding of the present invention that this quench sensitivity can be controlled with respect to a particularly preferred composition.
  • the alloy may be air cooled at a cooling rate from to 1,000F per minute, naturally with reasonable section thicknesses; otherwise, the alloy should be water quenched at the more rapid rate specified hereinabove.
  • the air cooling is normally achieved by using appropriately placed fans.
  • the hot working step should be performed at a finishing temperature in excess of 900F and preferably in excess of 950F.
  • EXAMPLE I ingots were prepared by direct chill (DC) casting in a conventional manner summarized as follows. Melting and alloying was carried out in a gas-fired, open hearth furnace. After alloying the melt was degassed by gaseous chlorine fluxing for 20 minutes. The average pouring temperature was 1,370F. The average casting speed was 4 5% inch per minute and the metal head was maintained between 2 A and 3 inch.
  • the composition of the alloys prepared are given in Table I below.
  • Measured surface temperatures ranged between 975 and 1025F before entering the press.
  • Three extrusion dies were used to produce section thicknesses of one-eighth, one-fourth, and one-half inch. Exit temperatures ranged from 980 to 1,000F.
  • One extrusion of each thickness was fan cooled as it exited from the press at a cooling rate in the range of the process of the present invention; another was water quenched by passing it through an open ended trough fed by an upward flow of water at both ends at a cooling rate in the range of the process of the present invention. All extrusions were aged at room temperature for about 24 hours, followed by artificial aging at 350F for 5 hours.
  • Tensile test specimens and Charpy impact specimens were taken from the extrusions.
  • One-eighth and V4 inch thick extrusions were tested with reduced width from the standard 0.394 inch and the impact test value was corrected for reduced area.
  • the excellent improved impact toughness was .iue to the retention of an unrecrystallized grain structure in the alloys.
  • the microstructure of both alloys was characterized by substantially all grains being fibrous and grossly elongated, with the length to thickness ratio being substantially greater than 25 to l.
  • the elongated grains contained a plurality of fine, uniform sub-grains which were visible under high magnification.
  • the precipitates formed by chromium, zirconium and manganese were favorably dispersed throughout the matrix.
  • EXAMPLE III lngots were prepared in a conventional manner from two kilogram melts cast by the tilt mold (Durville) process. The resultant compositions are indicated in Table III below.
  • Example 111 The alloys prepared in Example 111 were processed in the following manner. The ingots were homogenized at 1,025F for 12 hours. The ingots were hot rolled from 1,000F, 80% in one pass. The materials were quenched by plunging into water at room temperature, thus providing a cooling rate in the range of the process of the present invention. The materials were age hardened 5 hours at 350F. The materials were then tested for tensile properties and Charpy impact properties using ,4 inch specimens. The results are shown in Table IV below.
  • alloy of the present invention namely Alloys E and F gave surprising improved properties over comparative A1- Ioys C and D. It is noted that Alloy C does not contain the chromium addition and Alloy D does not contain the zirconium addition.
  • Comparative Alloys C and D were about percent recrystallized, with the recrystallized grains being substantially equiaxed.
  • the microstructure of Alloys E and F was substantially as described in Example II, with the length to thickness ratio being in excess of 15 to I.
  • Table IV Charpy Impact lngots were prepared in a manner after Example have the composition indicated in Table V below.
  • Alloy G was characterized by a completely recrystallized grain structure.
  • Alloy H of the present invention was substantially as described in Example 11, with the length to thickness ratio being in excess of 10 to 1.
  • A1- loys l and .1 were substantially unrecrystallized, with the length to thickness ratio being about 5 to 1.
  • Alloys 1 and J l acked the favorably uniform dispersion of chromium or manganese.
  • the alloy was extruded into a shape having a thickness of one-half inch using substantially the same procedure as outlined in Example 11, including a water quench as it exited from the extrusion press and an agingtreatment at 350F for 6 hours.
  • Alloys K and B in section thicknesses of one-half inch, were machined into Charpy V-Notch impact specimens and were impact tested.
  • Alloy B of the present invention had a Charpy impact strength of 55.8 foot pounds, while Alloy K had a Charpy impact strength of 10.8 foot pounds.
  • the broken impact specimens were then macro-etched to reveal the grain structure of the test pieces.
  • the drawing which forms a part of the present specification, shows Alloy B as the upper sample and Alloy K as the lower sample and is at a magnification of 2.5X.
  • FIGURE compares the high impact energy, 55.8 foot ounds, and the fgrossly elongated, fibrous rain strucure of Alloy B o the present invention, wit the essentially recrystallized structure and low impact energy, 10.8 foot pounds, of Alloy K.
  • a hot worked aluminum base alloy having high strength and high impact properties consisting essentially of silicon from 0.3 to 1.3 percent, magnesium from 0.3 to 1.5 percent, chromium from 0.03 to 0.40 percent, zirconium from 0.03 to 0.20 percent, balance essentially aluminum, wherein substantially all grains are fibrous and grossly elongated, with a length to thickness ratio as extruded of at least 10 to 1, wherein said elongated grains contain a plurality of sub-grains.
  • An alloy according to claim 1 containing magnesium from 0.4 to 1.0 percent.
  • microstructure contains chromium, zirconium and manganese in a uniform dispersion precipitated throughout the matrix.
  • An alloy according to claim 1 containing a material selected from the group consisting of titanium up to 0.10 percent, vanadium up to 0.15 percent, iron up to 0.60 percent, copper up to 0.30 percent, zinc up to 0.50 percent, boron up to 0.008 percent, and others each 010 percent max., total 0.50 percent max.
  • a hot worked aluminum base alloy having high strength and high impact properties consisting essentially of silicon from 0.3 to 1.3 percent, magnesium from 0.3 to 1.5 percent, chromium from 0.03 to 0.2 percent, zirconium from 0.03 to 0.2 percent, manganese from 0.03 to 0.2 percent, balance essentially aluminum, with the total chromium plus zirconium plus manganese content being from 0.2 to 0.35 percent, wherein substantially all grains are fibrous and grossly elongated containing a plurality of sub-grains, with a length to thickness ratio as extruded of at least 10 to 1, and wherein the microstructure contains chromium, zirconium and manganese in a uniform dispersion precipitated throughout the matrix.
  • An alloy according to claim 7 containing magnesium from 0.4 to 1.0 percent.
  • An alloy according to claim 7 containing a material selected from the group consisting of titanium up to 0.10 percent, vanadium up to 0.15 percent, iron up to 0.60 percent, copper up to 0.30 percent, zinc up to 0.5 percent, boron up to 0.008 percent, and others each 0.10 percent max., total 0.50 percent max.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Extrusion Of Metal (AREA)
US00193458A 1971-10-28 1971-10-28 Aluminum base alloys Expired - Lifetime US3717512A (en)

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JP (1) JPS5441970B2 (enrdf_load_stackoverflow)
BE (1) BE780611R (enrdf_load_stackoverflow)
CH (1) CH594056A5 (enrdf_load_stackoverflow)
DE (1) DE2213136A1 (enrdf_load_stackoverflow)
FR (1) FR2158782A6 (enrdf_load_stackoverflow)
IT (1) IT1045683B (enrdf_load_stackoverflow)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4619712A (en) * 1981-11-10 1986-10-28 Mitsubishi Light Metal Industries Limited Superplastic aluminum alloy strips and process for producing the same
EP1041165A1 (en) * 1999-04-02 2000-10-04 Kabushiki Kaisha Kobe Seiko Sho Shock absorbing material
US6562154B1 (en) * 2000-06-12 2003-05-13 Aloca Inc. Aluminum sheet products having improved fatigue crack growth resistance and methods of making same
WO2003054243A1 (de) * 2001-12-21 2003-07-03 Daimlerchrysler Ag Warm- und kaltumformbare aluminiumlegierung
US20100028101A1 (en) * 2008-07-30 2010-02-04 Olab S.R.L. Hot pressing process, particularly for providing metal unions for pneumatic, hydraulic and fluid-operated circuits, and metal union obtained thereby
US20110135533A1 (en) * 2009-12-03 2011-06-09 Alcan International Limited High strength aluminium alloy extrusion
US9556502B2 (en) 2012-07-16 2017-01-31 Arconic Inc. 6xxx aluminum alloys, and methods for producing the same
EP1785499B1 (de) 2005-11-14 2019-01-02 Otto Fuchs KG Energieabsorptionsbauteil
US10190196B2 (en) 2014-01-21 2019-01-29 Arconic Inc. 6XXX aluminum alloys
EP2553131B1 (en) 2010-03-30 2019-05-08 Norsk Hydro ASA High temperature stable aluminium alloy
US20210010109A1 (en) * 2019-07-10 2021-01-14 Kaiser Aluminum Fabricated Products, Llc Al-Mg-Si Alloy Exhibiting Superior Combination of Strength and Energy Absorption
US11359269B2 (en) * 2019-02-08 2022-06-14 GM Global Technology Operations LLC High strength ductile 6000 series aluminum alloy extrusions

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55131152A (en) * 1979-03-30 1980-10-11 Sumitomo Light Metal Ind Ltd Manufacture of a -mg-si type alloy with high extrudability and hardenability, and extruded material thereof

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3113052A (en) * 1960-07-05 1963-12-03 Aluminum Co Of America Method of making aluminum base alloy extruded product
US3234054A (en) * 1964-08-05 1966-02-08 Olin Mathieson Process for preparing aluminum base alloy

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3113052A (en) * 1960-07-05 1963-12-03 Aluminum Co Of America Method of making aluminum base alloy extruded product
US3234054A (en) * 1964-08-05 1966-02-08 Olin Mathieson Process for preparing aluminum base alloy

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4619712A (en) * 1981-11-10 1986-10-28 Mitsubishi Light Metal Industries Limited Superplastic aluminum alloy strips and process for producing the same
EP1041165A1 (en) * 1999-04-02 2000-10-04 Kabushiki Kaisha Kobe Seiko Sho Shock absorbing material
US6562154B1 (en) * 2000-06-12 2003-05-13 Aloca Inc. Aluminum sheet products having improved fatigue crack growth resistance and methods of making same
WO2003054243A1 (de) * 2001-12-21 2003-07-03 Daimlerchrysler Ag Warm- und kaltumformbare aluminiumlegierung
US20050095167A1 (en) * 2001-12-21 2005-05-05 Andreas Barth Hot-and cold-formed aluminum alloy
US20080078480A1 (en) * 2001-12-21 2008-04-03 Daimlerchrysler Ag Hot-and cold-formed aluminum alloy
EP1785499B1 (de) 2005-11-14 2019-01-02 Otto Fuchs KG Energieabsorptionsbauteil
US20100028101A1 (en) * 2008-07-30 2010-02-04 Olab S.R.L. Hot pressing process, particularly for providing metal unions for pneumatic, hydraulic and fluid-operated circuits, and metal union obtained thereby
US8313590B2 (en) 2009-12-03 2012-11-20 Rio Tinto Alcan International Limited High strength aluminium alloy extrusion
US20110135533A1 (en) * 2009-12-03 2011-06-09 Alcan International Limited High strength aluminium alloy extrusion
EP2553131B1 (en) 2010-03-30 2019-05-08 Norsk Hydro ASA High temperature stable aluminium alloy
US9556502B2 (en) 2012-07-16 2017-01-31 Arconic Inc. 6xxx aluminum alloys, and methods for producing the same
US9890443B2 (en) 2012-07-16 2018-02-13 Arconic Inc. 6XXX aluminum alloys, and methods for producing the same
US10190196B2 (en) 2014-01-21 2019-01-29 Arconic Inc. 6XXX aluminum alloys
US11359269B2 (en) * 2019-02-08 2022-06-14 GM Global Technology Operations LLC High strength ductile 6000 series aluminum alloy extrusions
US20220259710A1 (en) * 2019-02-08 2022-08-18 GM Global Technology Operations LLC High strength ductile 6000 series aluminum alloy extrusions
US11708629B2 (en) * 2019-02-08 2023-07-25 GM Global Technology Operations LLC High strength ductile 6000 series aluminum alloy extrusions
US20210010109A1 (en) * 2019-07-10 2021-01-14 Kaiser Aluminum Fabricated Products, Llc Al-Mg-Si Alloy Exhibiting Superior Combination of Strength and Energy Absorption

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CH594056A5 (enrdf_load_stackoverflow) 1977-12-30
DE2213136A1 (de) 1973-05-03
JPS4852613A (enrdf_load_stackoverflow) 1973-07-24
IT1045683B (it) 1980-06-10
BE780611R (fr) 1972-09-13
JPS5441970B2 (enrdf_load_stackoverflow) 1979-12-11
FR2158782A6 (enrdf_load_stackoverflow) 1973-06-15

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