WO2022229800A1 - Aluminum casting alloy for near net shaped casting of structural or non-structural components - Google Patents

Aluminum casting alloy for near net shaped casting of structural or non-structural components Download PDF

Info

Publication number
WO2022229800A1
WO2022229800A1 PCT/IB2022/053727 IB2022053727W WO2022229800A1 WO 2022229800 A1 WO2022229800 A1 WO 2022229800A1 IB 2022053727 W IB2022053727 W IB 2022053727W WO 2022229800 A1 WO2022229800 A1 WO 2022229800A1
Authority
WO
WIPO (PCT)
Prior art keywords
mass
mpa
alloy
aluminum
alloy according
Prior art date
Application number
PCT/IB2022/053727
Other languages
French (fr)
Inventor
Glenn Edwin BYCZYNSKI
Anthony Marco LOMBARDI
Sumanth Shankar
Zeng XIAOCHUN
Original Assignee
Nemak. S.A.B. De C.V.
Mcmaster University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from EP21180881.1A external-priority patent/EP4083242A1/en
Application filed by Nemak. S.A.B. De C.V., Mcmaster University filed Critical Nemak. S.A.B. De C.V.
Priority to CN202280031534.3A priority Critical patent/CN117280057A/en
Publication of WO2022229800A1 publication Critical patent/WO2022229800A1/en

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C1/00Making non-ferrous alloys
    • C22C1/02Making non-ferrous alloys by melting
    • C22C1/026Alloys based on aluminium
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D21/00Casting non-ferrous metals or metallic compounds so far as their metallurgical properties are of importance for the casting procedure; Selection of compositions therefor
    • B22D21/02Casting exceedingly oxidisable non-ferrous metals, e.g. in inert atmosphere
    • B22D21/04Casting aluminium or magnesium
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/56General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0068Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C21/00Alloys based on aluminium
    • C22C21/10Alloys based on aluminium with zinc as the next major constituent
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22FCHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C22F1/053Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with zinc as the next major constituent

Definitions

  • the invention relates to an aluminum casting alloy for near net shaped casting of structural or non-structural components.
  • the alloy contains 2 to 10 % by mass zinc (“Zn”), 0.5 to 5 % by mass magnesium (“Mg”), 0.5 to 5 % by mass iron (“Fe”), ⁇ 4 % by mass copper (“Cu”), ⁇ 0:5 % by mass titanium (“Ti”), ⁇ 0.1 % by mass strontium (“Sr”), ⁇ 0.2 % by mass beryllium (“Be”), ⁇ 0.5 % by mass zirconium (“Zr”), ⁇ 0.5 % by mass vanadium (“V”), 0.5 % by mass chromium (“Cr”), ⁇ 0.5 % by mass scandium (“Sc”), ⁇ 0.1 % by mass sodium (“Na”), ⁇ 0.5 % by mass silicon (“Si”), ⁇ 1 % by mass manganese (“Mn”),
  • the alloy may be subjected to heat treatment selected from the group consisting of solutionizing, incubation, aging, and two or more heat treatment steps.
  • the alloy known from WO 2018/094535 A1 comprises at least 1 ,5 % by mass Mg, 4 - 10 % by mass Zn, and 1,5 - 3 % by mass Fe, a first exemplary embodiment of the alloy consisting of 5 % by mass Zn, 2 % by mass Mg, 0.35 % by mass Cu, 1.5 % by mass Fe, and Al as balance and a second exemplary embodiment of the alloy consisting of 5 % by mass, Zn 2 % by mass Mg and 1.5 % by mass Fe, balance Al.
  • Both alloys were cast by high pressure die casting with vacuum assistance, a thin walled part manufactured from the first alloy having a yield strength of 200 MPa, an ultimate tensile strength of 315 MPa and an elongation of 3.80 % in the as-cast state with 21 days of natural aging and a large scale part manufactured from the second alloy showing a yield strength of 201 MPa, an ultimate tensile strength of 312 MPa and an elongation of 4.63 % in the as-cast state.
  • WO 2018/094535 A1 discloses side door impact beams made from alloys which contain 5.0 % by mass Zn, 2.0 % by mass Mg, 0 or 0,35 % by mass of Cu, 1.5 % by mass of Fe, and Al as balance respectively.
  • the optimized mechanical properties of the parts which have been alloyed and manufactured in accordance with the specifications given in WO 2018/094535 A1 have been achieved not only by a purposeful adjustment of the contents of the alloying elements but also by equally purposefully heat treating the respective part.
  • an AIZnMg casting alloy is disclosed.
  • This known alloy consists of 3.0 to 4.5 % by mass Zn, 0.1 to 1.5 % by mass Mg and 0.5 to 1.5 % by mass Fe, balance Al and impurities, wherein the impurities may include contents of Ti, Cr and other elements with a respective content of up to 0.1 % by mass, in particular up to 0.01 % by mass.
  • the exemplary embodiments of the alloy contain 1.88 to.4.05 % by mass of Zn, 0.17 to 1.35 % by mass of Mg, 0.52 to 1.02 % by mass of Fe, balance Al.
  • the castings can also be subjected to age hardening or precipitation hardening, which can be performed as "natural aging” by exposing the castings to room temperature for several days, or as “artificial aging", in which the castings are usually also kept at elevated temperatures for several days to intensify and accelerate the hardness-increasing effect.
  • age hardening or precipitation hardening can be performed as "natural aging” by exposing the castings to room temperature for several days, or as “artificial aging”, in which the castings are usually also kept at elevated temperatures for several days to intensify and accelerate the hardness-increasing effect.
  • the object to be solved by the invention was to provide an aluminum alloy for high pressure die casting that offers a combination of properties that meets the requirements of structural, body-in- white and electrification components (battery enclosures). These requirements include ultimate tensile strengths (UTS), yield strength (YS), tensile elongation (%EI) and . sufficient ductility for joinability without the necessity of an elaborate and cost intensive heat treatment.
  • UTS ultimate tensile strengths
  • YS yield strength
  • %EI tensile elongation
  • the further object was to provide a method by means of which parts, which show an optimized combination of mechanical properties can be manufactured by using high pressure die casting in a practice-oriented manner.
  • an aluminum casting alloy for near net shaped casting of structural or non-striictural parts thus consists of, in % by mass
  • V ⁇ 0.2 %
  • B ⁇ 0.04 %;. balance Al and unavoidable impurities, the sum of the contents of the impurities being ⁇ 0.1 %.
  • the invention has selected an aluminum alloy which has an optimized combination of strength, ductility, elongation, and joinability. This enables increased lightweighting opportunities of parts cast from the alloy according to the invention due to the higher strength and comparable performance in energy absorption in the event of a crash.
  • each alloying element as follows:
  • G.P; Zones Guinier-Preston zones, see https://en.wikipedia.org/wiki/Guinier-Preston_zone) that are formed during natural aging.
  • the range of 4.5 - 7.5 % by mass Zn and 0.7 - 2.0 % by mass Mg are required to have the necessary combination of strength and ductility.
  • the positive influence Zn has on the strength of the parts cast from the alloy according to the invention can reliably be achieved, if the Zn-content of the alloy according to the invention is at least 4.6 % by mass, preferably at least 4.7 % by mass oral least 4.75 % by mass.
  • the Zn content of the alloy according to the invention can be limited to a maximum of 5.5 % by mass, in particular to a maximum of 5.0 % by mass.
  • a high strength variant of the alloy according to the invention can be obtained by setting the minimum Zn content to 5.0 % by mass and the maximum Zn content to 5.5 % by mass.
  • the cast alloy according to the invention shows high elongation properties.
  • the Mg content can be limited to a maximum of 1.5 % by mass, preferably to 1.0 % by mass for this purpose.
  • An aluminum casting alloy according to the invention which provides in the as- cast state (“F-temper”) an elongation ranging from 11 to 15 % in combination with a yield strength of 140 to 160 MPa and an ultimate tensile strength in the range of 280 to 300 MPa thus, according to the invention, preferably contains 4.6 to 5.0 % by mass Zn and 0.8 to 1.0 % by mass Mg.
  • the cast part cast from aluminum alloy alloyed in this manner be optionally subjected to a T4 treatment.
  • a high strength variant of the alloy of the invention can be obtained by adjusting the Zn content of the alloy according to the invention to 5.0 to 5.5 % by mass and the Mg content of the alloy according to the invention to 1.6 to 2.0 % by mass, preferably 1.6 to 1.9 % by mass.
  • the embodiment of the alloy according to the invention alloyed in this way has an ultimate tensile strength of 300 to 340 MPa and a yield strength of 180 to 210 MPa in combination with an elongation of 4 to 7 % in the as-cast state (“F-temper”).
  • the parts cast from the alloy alloyed in accordance with the invention containing 5.0 to 5.5 % by mass Zn and 1.6 to 2.0 % by mass Mg have a yield strength of 210 to 230 MPa, an ultimate tensile strength of 340 to 387 MPa, and an elongation of 7 to 11 %
  • the parts cast from this alloy have a yield strength ranged from 350 to 400 MPa and an ultimate tensile strength from 380 to 450 MPa, while their elongation ranges between 2 - 5 %.
  • Further lightweighting opportunities can exist using the high strength variant of the alloy according to the invention in applications that require the ultra- high strength given by this alloy, specifically in the T7 condition, but can tolerate lower elongation/ductility.
  • Fe contents above 1 % by mass will also significantly reduce the susceptibility to die soldering, which improves die life and reduces distortion in the castings.
  • at least 0.8 % by mass Fe are needed, Fe contents of at least 1.0 % by mass being especially advantageous in this regard.
  • Fe contents of more than 2.0 % by mass should be avoided, to prevent the excessive formation of coarse primary AI13Fe4 platelets which are deleterious to alloy ductility. Negative influences of the presence of Fe in the alloy according to the invention can be prevented if, in particular, the Fe content is limited to a maximum of 1.8 % by mass or to a maximum of 1.5 % by mass.
  • the Cu content should be restricted to below 0.1 % by mass as it is deleterious to corrosion resistance and increases hot tearing susceptibility.
  • V can be optionally added as a modifying agent. Vanadium promotes the formation of the fibrous Al 6 Fe eutectic phase in favour of the acicular Al 13 Fe 4 , eutectic which will lead to improved ductility ; To use this effect, a minimum V content of at least 0.05 % by mass, in particular of at least 0.1 % by mass can be provided. This can counteract the negative effects of slower cooling rates or interactions with Si if present. The maximum of the optional V content is limited to 0.2 % by mass, in particular to 0.1 % by mass, because higher V contents do not efficiently contribute to the properties of the alloy according to the invention.
  • Figures 2a and 2b show a comparison of the ultimate tensile strength UTS, the yield strength YS and the elongation %EL samples made from the H700 alloy in the F-temper state to samples of the current structural die casting alloys AISi8MnMg and AISi10MnMg in F-temper (Fig. 2a) and in heat treated T5 or T7 condition (Fig. 2b).

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Continuous Casting (AREA)
  • Materials For Medical Uses (AREA)

Abstract

The invention provides an aluminum alloy for high pressure die casting that offers an optimized combination of ultimate tensile strengths (UTS), yield strength (YS), tensile elongation (%EI), and sufficient ductility for joinability without the necessity of an elaborate and cost intensive heat treatment. For this purpose an aluminum casting alloy for near net shaped casting of structural or non-structural components according to the invention consists of. in % by mass, Zn: 4.5 - 7.5 %, Mg: 0.7 - 2.0 %, Fe: 0.8 - 2.0 %, Si: < 0.3 %, Cu: < 0.1 %, V: ≤ 0.2 %, Ti: 0.2 %, B: < 0,04 %, balance Al and unavoidable impurities, the sum of the contents of the impurities being ≤ 0.1 %. On the basis of this alloy the invention also provides a method for the manufacture of a cast part which has a yield strength of 180 to 200 MPa, an ultimate tensile strength of 300 to 320 MPa and an elongation of 11 to 14 % and a method for the manufacture of a cast part which has a yield strength of 210 to 400 MPa, an ultimate tensile strength of 340 to 450 MPa and an elongation of 2 to 11 %.

Description

ALUMINUM CASTING ALLOY FOR NEAR NET SHAPED CASTING OF STRUCTURAL OR NON-STRUCTURAL COMPONENTS
The invention relates to an aluminum casting alloy for near net shaped casting of structural or non-structural components.
All information on contents of the aluminum alloy compositions indicated in the present application are related to mass, unless explicitly stated otherwise. All % data referring to the composition of a aluminum alloy or another alloy mentioned here without referring to a reference unit, should therefore be understood as information in "% by mass" (“mass %”).
Mechanical properties such as tensile strength, yield strength and elongation that are reported here were determined in a tensile test according to ASTM B557 standard unless expressly indicated otherwise.
From WO 2018/Q94535 A1 , the content of which is incorporated by reference in the present application, an aluminum alloy for near net shaped high pressure die casting of structural components is already known. The alloy contains 2 to 10 % by mass zinc (“Zn”), 0.5 to 5 % by mass magnesium (“Mg”), 0.5 to 5 % by mass iron (“Fe”), ≤ 4 % by mass copper (“Cu”), ≤ 0:5 % by mass titanium (“Ti”), ≤ 0.1 % by mass strontium (“Sr”), ≤ 0.2 % by mass beryllium (“Be”), ≤ 0.5 % by mass zirconium (“Zr”), ≤ 0.5 % by mass vanadium (“V”), 0.5 % by mass chromium ("Cr”), ≤ 0.5 % by mass scandium (“Sc”), ≤ 0.1 % by mass sodium (“Na”), ≤ 0.5 % by mass silicon (“Si”), ≤ 1 % by mass manganese (“Mn”), ≤ 5 % by mass nickel (“Ni"), ≤ 0.5 % by mass boron (“B”), and ≤ 1 % by mass molybdenum (“Mo”), with balance aluminum (“Al”). The alloy may be subjected to heat treatment selected from the group consisting of solutionizing, incubation, aging, and two or more heat treatment steps. According to a preferred embodiment, the alloy known from WO 2018/094535 A1 comprises at least 1 ,5 % by mass Mg, 4 - 10 % by mass Zn, and 1,5 - 3 % by mass Fe, a first exemplary embodiment of the alloy consisting of 5 % by mass Zn, 2 % by mass Mg, 0.35 % by mass Cu, 1.5 % by mass Fe, and Al as balance and a second exemplary embodiment of the alloy consisting of 5 % by mass, Zn 2 % by mass Mg and 1.5 % by mass Fe, balance Al. Both alloys were cast by high pressure die casting with vacuum assistance, a thin walled part manufactured from the first alloy having a yield strength of 200 MPa, an ultimate tensile strength of 315 MPa and an elongation of 3.80 % in the as-cast state with 21 days of natural aging and a large scale part manufactured from the second alloy showing a yield strength of 201 MPa, an ultimate tensile strength of 312 MPa and an elongation of 4.63 % in the as-cast state.
Other small scale parts made from the Al-alloy disclosed in WO 2018/094535 A1 consists of alloys with 4.74 to 6.17 by mass % of Zn, 2.1 to 2,24 % by mass of Mg, 0.07 to 0.38 % by mass of Cu, 1.56 to 3.78 % by mass of Fe, 0.02 to 0.24 % by mass of Mn, whereas large scale applications were made of Al-alloys which contain 5.16 to 5.21 % by mass of Zn, 1.54 to 2.0 % by mass of Mg; 0.8 % by mass of Cu, 1.02 to 1.6 % by mass of Fe, 0.04 or 0.035 % by mass of Si, 0.10 to 0, 15 % by mass of Ti, 0.13 % by mass of Zr, 0.057 % by mass of V, balance Al.
Further, WO 2018/094535 A1 discloses side door impact beams made from alloys which contain 5.0 % by mass Zn, 2.0 % by mass Mg, 0 or 0,35 % by mass of Cu, 1.5 % by mass of Fe, and Al as balance respectively. The optimized mechanical properties of the parts which have been alloyed and manufactured in accordance with the specifications given in WO 2018/094535 A1 have been achieved not only by a purposeful adjustment of the contents of the alloying elements but also by equally purposefully heat treating the respective part.
Also in Korean patent KR 10 1469613 B1 an AIZnMg casting alloy is disclosed. This known alloy consists of 3.0 to 4.5 % by mass Zn, 0.1 to 1.5 % by mass Mg and 0.5 to 1.5 % by mass Fe, balance Al and impurities, wherein the impurities may include contents of Ti, Cr and other elements with a respective content of up to 0.1 % by mass, in particular up to 0.01 % by mass. The exemplary embodiments of the alloy contain 1.88 to.4.05 % by mass of Zn, 0.17 to 1.35 % by mass of Mg, 0.52 to 1.02 % by mass of Fe, balance Al.
It is common knowledge of an expert in the field of aluminum casting that the mechanical properties of parts cast from aluminum alloys can strongly be influenced by an appropriate heat treatment. For example, aluminum castings can be subjected to a homogenization or solution heat treating to remove inhomogeneities of the structure of the cast part. Further, an annealing treatment ("tempering") can be performed to cause a reduction in strength, while at the same time increasing the ductility. To increase the strength the castings can also be subjected to age hardening or precipitation hardening, which can be performed as "natural aging" by exposing the castings to room temperature for several days, or as "artificial aging", in which the castings are usually also kept at elevated temperatures for several days to intensify and accelerate the hardness-increasing effect. To designate the heat treatment condition of aluminum castings a designation system has been developed, which, for example, is explained in "Introduction to Aluminum Alloys and Tempers," J. Gilbert Kaufman, p 39-76, chapter "Understanding the Aluminum Temper Designation System," DOl:10.1361/iaat2000p039, and in WO 2018/094535 A1 as well.
Against the background of the prior art the object to be solved by the invention was to provide an aluminum alloy for high pressure die casting that offers a combination of properties that meets the requirements of structural, body-in- white and electrification components (battery enclosures). These requirements include ultimate tensile strengths (UTS), yield strength (YS), tensile elongation (%EI) and . sufficient ductility for joinability without the necessity of an elaborate and cost intensive heat treatment.
The further object was to provide a method by means of which parts, which show an optimized combination of mechanical properties can be manufactured by using high pressure die casting in a practice-oriented manner.
The invention has achieved this object on the one hand by a cast alloy having the features specified in claim 1.
As a further solution the invention proposes the methods indicated in claims 13 and 14 for the manufacture of cast parts which show an optimized combination of mechanical properties.
Advantageous embodiments of the invention are defined in the dependent claims and, like the general concept of the invention, are explained in detail in the following.
According to the invention an aluminum casting alloy for near net shaped casting of structural or non-striictural parts thus consists of, in % by mass,
Zn: 4.5 - 7.5 %;
Mg: 0.7 - 2.0 %;
Fe: 0.8 - 2.0 %;
Si: < 0.3 %;
Cu: < 0.1 %;
V: ≤ 0.2 %;
Ti: ≤ 0.2 %;
B: ≤ 0.04 %;. balance Al and unavoidable impurities, the sum of the contents of the impurities being ≤ 0.1 %.
Starting from the prior art disclosed in WO 2018/094535 A1, the invention has selected an aluminum alloy which has an optimized combination of strength, ductility, elongation, and joinability. This enables increased lightweighting opportunities of parts cast from the alloy according to the invention due to the higher strength and comparable performance in energy absorption in the event of a crash.
To this end, the invention has selected the contents of each alloying element as follows:
Zn and Mg are added as strengthening elements through the formation of Mg and Zn rich G.P. Zones (“G.P; Zones” = Guinier-Preston zones, see https://en.wikipedia.org/wiki/Guinier-Preston_zone) that are formed during natural aging.
The range of 4.5 - 7.5 % by mass Zn and 0.7 - 2.0 % by mass Mg are required to have the necessary combination of strength and ductility.
In particular, the positive influence Zn has on the strength of the parts cast from the alloy according to the invention can reliably be achieved, if the Zn-content of the alloy according to the invention is at least 4.6 % by mass, preferably at least 4.7 % by mass oral least 4.75 % by mass. To obtain a cast part which has an optimized deformation capacity and elongation the Zn content of the alloy according to the invention can be limited to a maximum of 5.5 % by mass, in particular to a maximum of 5.0 % by mass. However, a high strength variant of the alloy according to the invention can be obtained by setting the minimum Zn content to 5.0 % by mass and the maximum Zn content to 5.5 % by mass. The addition of approximately 5 % by mass Zn also reduces the Al-Fe eutectic point from 1.7 % by mass in the binary alloy to approximately 1.3 % by mass, enabling the alloy according to the invention even in the high strength variant to be a near-eutectic alloy, thereby improving fluidity and reducing hot tearing susceptibility.
By limiting the Mg content to a maximum of 2.0 % by mass the cast alloy according to the invention shows high elongation properties. In particular, the Mg content can be limited to a maximum of 1.5 % by mass, preferably to 1.0 % by mass for this purpose. By adjusting the Mg content of the alloy according to the invention to at least 0.7 % by mass, in particular at least 0.8 % by mass, the positive influence Mg has on the properties of the alloy according to the invention and the parts cast from this alloy can be used in a particular reliable manner.
An aluminum casting alloy according to the invention which provides in the as- cast state (“F-temper”) an elongation ranging from 11 to 15 % in combination with a yield strength of 140 to 160 MPa and an ultimate tensile strength in the range of 280 to 300 MPa thus, according to the invention, preferably contains 4.6 to 5.0 % by mass Zn and 0.8 to 1.0 % by mass Mg. For further increases in strength for this variant of the alloy according to the invention without a loss in ductility, the cast part cast from aluminum alloy alloyed in this manner be optionally subjected to a T4 treatment. Accordingly, in a first method according to the invention which enables the manufacture of a cast part which has a yield strength of 180 to 200 MPa, an ultimate tensile strength of 300 to 320 MPa, and an elongation of 11 to 14 % the following working steps are performed: a) Providing an aluminum melt alloyed in accordance with the invention, the melt containing 4.6 to 5.0 % by mass Zn and 0.8 to 1.0 % by mass Mg; b) Casting a cast part from the aluminum melt; c) Subjecting the cast part to a T4 temper treatment which involves a solution heat treatment at temperatures of 460 to 480 °C for 1 to 8 h optionally followed by a forced air quench and natural aging for 14 to 75 days. As an alternative, a high strength variant of the alloy of the invention can be obtained by adjusting the Zn content of the alloy according to the invention to 5.0 to 5.5 % by mass and the Mg content of the alloy according to the invention to 1.6 to 2.0 % by mass, preferably 1.6 to 1.9 % by mass. The embodiment of the alloy according to the invention alloyed in this way has an ultimate tensile strength of 300 to 340 MPa and a yield strength of 180 to 210 MPa in combination with an elongation of 4 to 7 % in the as-cast state (“F-temper”).
Also here a further increase of the mechanical properties of the parts cast from this embodiment of the alloy according to the invention can be obtained by subjection the cast part to a treatment.
Accordingly, in a second method according to the invention which enables the manufacture of a cast part which has a yield strength of 210 to 400 MPa, an ultimate tensile strength of 340 to 450 MPa and an elongation of 2 to 11 % the following working steps are performed: a) Providing an aluminum melt alloyed in accordance with the invention, the melt containing 5.0 to 5.5 % by mass Zn and 1.6 to 2.0 % by mass Mg; b) Casting a cast part from the aluminum melt; c) Subjecting the cast part to heat treatment, wherein c.1 ) the heat treatment is a T4 temper treatment which involves a solution heat treatment at temperatures of 450 to 480 °C for 2 to 24 h optionally followed by a forced air or water quench and natural aging for 7 to 75 days or c.2) the heat treatment is a T7 temper treatment which involves a solution heat treatment at temperatures of 450 to 480 °C for 2 to 24 h followed by forced air or water quench and 1-2 days of natural aging and an artificial aging at temperatures between 120 to 200 °C for i to 24 h in single or dual-stage aging. In the T4 temper state the parts cast from the alloy alloyed in accordance with the invention containing 5.0 to 5.5 % by mass Zn and 1.6 to 2.0 % by mass Mg have a yield strength of 210 to 230 MPa, an ultimate tensile strength of 340 to 387 MPa, and an elongation of 7 to 11 %, whereas in in the T7 temper state the parts cast from this alloy have a yield strength ranged from 350 to 400 MPa and an ultimate tensile strength from 380 to 450 MPa, while their elongation ranges between 2 - 5 %. Further lightweighting opportunities can exist using the high strength variant of the alloy according to the invention in applications that require the ultra- high strength given by this alloy, specifically in the T7 condition, but can tolerate lower elongation/ductility.
It’s recommended that, preferably, a minimum of 20 days of natural aging should be given to the parts cast from the alloy according to the invention prior to use in service. Yield strength will continue to gradually increase until approximately 75 days of natural aging, where further natural aging time produces very minor changes in strength. Elongation is not significantly affected by natural aging time.
0.8 to 2.0 % by mass Fe is present in the alloy . according to the invention to enable the formation of Al-Fe based eutectic phases which improve fluidity and reduce hot tearing susceptibility, thereby making the alloy castable to near-net shape in high pressure die casting. In addition, Fe contents above 1 % by mass will also significantly reduce the susceptibility to die soldering, which improves die life and reduces distortion in the castings. For this purpose, at least 0.8 % by mass Fe are needed, Fe contents of at least 1.0 % by mass being especially advantageous in this regard. Fe contents of more than 2.0 % by mass should be avoided, to prevent the excessive formation of coarse primary AI13Fe4 platelets which are deleterious to alloy ductility. Negative influences of the presence of Fe in the alloy according to the invention can be prevented if, in particular, the Fe content is limited to a maximum of 1.8 % by mass or to a maximum of 1.5 % by mass.
The Si content should be limited to below 0.3 % by mass, in particular below 0.2 % by mass, to prevent the formation of harmful Fe based intermetallic phases such as β-AIFeSi which would be deleterious to the alloy’s ductility. The addition of S i should also be limited to prevent excessive Mg2Si formation, which depletes Mg and reduces the amount of G.P. Zones that are formed during natural aging and would impair alloy strengthening in the F-temper state.
The Cu content should be restricted to below 0.1 % by mass as it is deleterious to corrosion resistance and increases hot tearing susceptibility.
V can be optionally added as a modifying agent. Vanadium promotes the formation of the fibrous Al6Fe eutectic phase in favour of the acicular Al13Fe4, eutectic which will lead to improved ductility ; To use this effect, a minimum V content of at least 0.05 % by mass, in particular of at least 0.1 % by mass can be provided. This can counteract the negative effects of slower cooling rates or interactions with Si if present. The maximum of the optional V content is limited to 0.2 % by mass, in particular to 0.1 % by mass, because higher V contents do not efficiently contribute to the properties of the alloy according to the invention.
Ti can be optionally added in amounts of up to 0.2 % by mass for grain refinement and reduction of hot tearing susceptibility. This effect can already be obtained by adding at least 0,05 % by mass Ti, in particular at least 0.1 % by mass. The maximum of the optional Ti content is limited to 0.2 % by mass, in particular to 0.1 % by mass, because higher Ti contents do not contribute to the properties of the alloy according to the invention.
The Ti can be added to the melt alloyed in accordance with the invention in the form of an AI-5Ti-1 B master alloy, which results in a maximum B content of 0.04 % by mass.
The remainder of the ailoy according to the invention is formed by Al and technically unavoidable impurities. Elements including Na, Ca, K, Li, Ni, Cr and Mn typically belong to these impurities. The content of the respective impurities is set so low that in each case the respective impurity, has no influence on the properties of the alloy and the part cast therefrom. For this purpose, the total content of impurities in an alloy according to the invention is limited to 0.1 % by mass.
The specification for an aluminum casting alloy provided by the invention enables a combination of high ductility and improved strength compared to currently available alloys in the as-cast (F-temper) condition eliminating the need for heat treatments and associated post-processing. However, if the properties present in the as-cast state are not sufficient, they can be further improved by the heat treatments disclosed here.
The alloy according to the invention is especially suitable to be cast into nearnet shape components using High Pressure Die Casting (“HPDC”) with or without the application of vacuum. In this regard it turns to be out particularly advantageous that the alloy is based on the Al-Fe eutectic system, which enables the alloy to be castable in HPDC when Fe content exceeds 1 % by mass. Due to the composition targets provided by the invention additional benefits of the alloy according to the invention include an improved repyclability compared to the state of the art primary aluminum alloys as well as superior HPDC die life.
The alloy H700, based on which the properties shown in Fig. 1a to 2b were determined consists of 4.6 % by mass Zn, 0.8 % by mass Mg, 1.2 % by mass Fe, 0.07 % by mass Si and 0.05 % by mass Ti.
Figures 1a and 1b show the ultimate tensile strength UTS and the yield strength YS of the H700 in the F-temper state as a function of natural aging time.
Figures 2a and 2b show a comparison of the ultimate tensile strength UTS, the yield strength YS and the elongation %EL samples made from the H700 alloy in the F-temper state to samples of the current structural die casting alloys AISi8MnMg and AISi10MnMg in F-temper (Fig. 2a) and in heat treated T5 or T7 condition (Fig. 2b). The T5 treatment, which the AISi8MnMg alloy samples were exposed to, consisted of artificial aging at 210 °C for 1 h followed by cooling in still air, whereas the T7 treatment, the AISi10MnMg alloy samples were exposed to, consisted of solutionizing at 450 °C for 12 hours, heating to 475 °C with a heating rate of 5 °C/h, holding the samples at 475 °C for 7 hours followed by water quenching. After the solutionizing treatment the samples underwent ah natural aging (..incubation”) treatment for 24 hours followed by an artificial aging in the course of which the samples were held at 120 °C for 24 hours followed by holding the samples at 160 °C for 24 hours.
FIG. 3 shows representative load-displacement curves from 3-point bend test for the H700 alloy samples in F-temper, for the AISi8MnMg samples in F-temper and for the AISi10MnMg samples In the T7 temper state. The 3-point bend test was performed in accordance with the Ford BB119-01 specification, which is a modified version of the VDA 238-100 standard test.
As can be seen from Figures 4a to 4d the H700 alloy according to the invention showed excellent joinability to both aluminum sheets made of aluminum extrusion alloy 6082-T6 and steel sheets made of dual phase steel DP600, material number according to EN 10027-2:1992-09: 1.0936 using self-piercing rivets (SPR), which is a common practice for joining automotive structural components to form the body-in-white.
Fig. 4a shows a longitudinal section of a SPR joint between a part made of the H700 according to the invention and the sheet made from the 6082-T7 Al alloy.
Fig. 4b shows a top view on the SPR joint as seen from the side on which the part cast from the H700 part is arranged.
Fig. 4c shows a longitudinal section of a SPR joint between a part made of the H700 according to the invention and the sheet made from the CP600 steel alloy. Fig. 4d shows a top view on the SPR joint as seen from the side on which the part cast from the H700 part is arranged. There were no cracks in the SPR joints and the interlocking between the rivets and the joining materials were within the acceptable ranges for joining automotive structural parts.
Fig. 5 shows the development of the yield strength YS of a specimens cast from AI-5Zn-2Mg-1 ,3Fe alloy according to the invention in response to the duration of a natural aging at room temperature.
Further specimens cast from the AI-5Zn-2Mg-1.3Fe alloy according to the invention were exposed to a) a natural aging for 70 days in the as cast condition, b) a T4 treatment in which the respective specimens were solution annealed at 450 °C for 12 hours, then heated with a heating rate of 5 °C/hour to 475 °C at which temperature the specimen were held for another 4 hours; c) a T6 treatment in which the respective specimens were
- solution annealed at 450 °C for 12 hours, then heated with a heating rate of 5 °C/hour to 475 °C at which temperature the specimens were held for another 4 to 7 hours,
- forced air cooled or water quenched from the solution annealing temperature to room temperature and naturally aged for 24 hours,
- naturally aged (“incubated") for 24 hours, and
- artificially aged at 120 °C for 24 hours and 170 °C for 3 hours; d) a T7 treatment in which the respective specimens were
- solution annealed at 450 °C for 12 hours, then heated with a heating rate of 5 °C/hour to 475 °C at which temperature the specimens were held for another 7 to 14 hours, - forced air cooled or water quenched from the solution annealing temperature to room temperature
- naturally aged (“incubated”) for 24 hours, and
- artificially aged at 120 °C for 24 hours and 170 °C for 14 hours.
The mechanical properties yield strength YS, ultimate tensile strength UTS and Elongation E the respective specimens show after the respective heat treatment are summarized in Table 1.
Figure imgf000015_0001

Claims

1 An aluminum casting alloy for near net shaped casting of structural or non- structural components, the aluminum casting alloy consisting of, in % by mass,
Zn: 4.5 - 7,5%;
Mg: 0.7 - 2.0%;
Fe: 0.8 - 2.0%;
Si: < 0.3%;
Cu: < 0.1 %;
V: ≤ 0.2%;
Ti: ≤ 0.2%;
B: ≤ 0.04%; balance Al and unavoidable impurities, the sum of the contents of the impurities being ≤ 0.1 %.
2. The aluminum casting alloy according to claim 1 characterized in that its Zn content is not more than 5.5 % by mass.
3. The aluminum casting alloy according to any of the preceding claims characterized in that its Zn content is at least 4.6 % by mass.
4. The aluminum casting alloy according to any of the preceding claims characterized in that its Mg content is not more than 1.0 % by mass.
5. The aluminum casting alloy according to any of the preceding claims characterized in that its Mg content is at least 0.8 % by mass.
6. The aluminum casting alloy according to claim 1 characterized in that its Fe content is not more than 1.5 % by mass.
7. The aluminum casting alloy according to any of the preceding claims characterized in that its Fe content is at least 1.0 % by mass.
8. The aluminum casting alloy according to any of the preceding claims characterized in that its Si content is less than 0,2 % by mass.
9. The aluminum casting alloy according to any of the preceding claims characterized in that it contains at least 0.05 % by mass of Ti.
10, The aluminum casting alloy according to any of the preceding claims characterized in that it contains at least 0,1 % by mass of V.
11. The aluminum casting alloy according to any of the preceding claims characterized in that the alloy contains 4.6 to 5.0 % by mass Zn and 0.8 to 1.0 % by mass Mg and that it has in the as-cast state (“F- temper”) a yield strength of 140 to 160 MPa, an ultimate tensile strength in the range of 280 to 300 MPa and elongation ranging from 11 to 14 %.
12. The aluminum casting alloy according to any of claims 1 to 10, characterized in that the alloy contains 5.0 to 5.5 % by mass Zn and 1.6 to 2.0 % by mass Mg and that it has in the as-cast state (“F- temper”) a yield strength of 180 to 210 MPa, an ultimate tensile strength in the range of 300 to 340 MPa and an elongation ranging from 4 to 7 %.
13. Method for the manufacture of a cast part which has a yield strength of 180 to 200 MPa, an ultimate tensile strength of 300 to 320 MPa and an elongation of 11 to 14 % comprising the following working steps: a) Providing an aluminum melt alloyed in accordance with claim 11 ; b) Casting a cast part from the aluminum melt; c) Subjecting the cast part to a T4 temper treatment which involves a solution heat treatment at temperatures of 460 to 480 °C for 1 to 8 h optionally followed by a forced air quench and natural aging for 14 to 75 days.
14. Method for the manufacture of a cast part which has a yield strength of 210 to 400 MPa, an ultimate tensile strength of 340 to 450 MPa and an elongation of 2 to 11 % comprising the following working steps: a) Providing an aluminum melt alloyed in accordance with claim 12; b) Casting a cast part from the aluminum melt; c) Subjecting the cast part to heat treatment, wherein c.1) the heat treatment is a T4 temper treatment which involves a solution heat treatment at temperatures of 450 to 480 °C for 2 to 24 h optionally followed by a forced air or water quench and natural aging for 7 to 75 days or c.2) the heat treatment is a T7 temper treatment which involves a solution heat treatment at temperatures of 450 to 480 °C for 2 to 24 h followed by forced air or water quench and 1-2 days of natural aging and an artificial aging at temperatures between 120 to 200 °C for 1 to 24 h in single or dual-stage aging.
PCT/IB2022/053727 2021-04-30 2022-04-21 Aluminum casting alloy for near net shaped casting of structural or non-structural components WO2022229800A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202280031534.3A CN117280057A (en) 2021-04-30 2022-04-21 Cast aluminum alloy for near net shape casting of structural or non-structural members

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP21171617 2021-04-30
EP21171617.0 2021-04-30
EP21180881.1 2021-06-22
EP21180881.1A EP4083242A1 (en) 2021-04-30 2021-06-22 Aluminum casting alloy for near net shaped casting of structural or non-structural components

Publications (1)

Publication Number Publication Date
WO2022229800A1 true WO2022229800A1 (en) 2022-11-03

Family

ID=81448920

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2022/053727 WO2022229800A1 (en) 2021-04-30 2022-04-21 Aluminum casting alloy for near net shaped casting of structural or non-structural components

Country Status (2)

Country Link
EP (1) EP4137595A1 (en)
WO (1) WO2022229800A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115961195A (en) * 2022-12-28 2023-04-14 亚太轻合金(南通)科技有限公司 High-pressure cast aluminum alloy and preparation method thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101469613B1 (en) 2012-08-21 2014-12-05 한국생산기술연구원 Al-Zn ALLOY HAVING HIGH THERMAL CONDUCTIVITY FOR DIE CASTING
US20150218678A1 (en) * 2012-08-21 2015-08-06 Korea Institute Of Industrial Technology Al-zn alloy for die casting having both high strength and high thermal conductivity
WO2018094535A1 (en) 2016-11-28 2018-05-31 Sumanth Shankar Aluminium alloys for structural and non-structural near net casting, and methods for producing same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101469613B1 (en) 2012-08-21 2014-12-05 한국생산기술연구원 Al-Zn ALLOY HAVING HIGH THERMAL CONDUCTIVITY FOR DIE CASTING
US20150218678A1 (en) * 2012-08-21 2015-08-06 Korea Institute Of Industrial Technology Al-zn alloy for die casting having both high strength and high thermal conductivity
WO2018094535A1 (en) 2016-11-28 2018-05-31 Sumanth Shankar Aluminium alloys for structural and non-structural near net casting, and methods for producing same
US20190376166A1 (en) * 2016-11-28 2019-12-12 Mcmaster University Aluminium alloys for structural and non-structural near net casting, and methods for producing same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
J. GILBERT KAUFMAN, INTRODUCTION TO ALUMINUM ALLOYS AND TEMPERS, pages 39 - 76

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115961195A (en) * 2022-12-28 2023-04-14 亚太轻合金(南通)科技有限公司 High-pressure cast aluminum alloy and preparation method thereof
CN115961195B (en) * 2022-12-28 2024-05-14 亚太轻合金(南通)科技有限公司 High-pressure casting aluminum alloy and preparation method thereof

Also Published As

Publication number Publication date
EP4137595A1 (en) 2023-02-22

Similar Documents

Publication Publication Date Title
CN106521253B (en) A kind of high formability Al Mg Si alloys and its manufacture method
CN102639733A (en) Improved 5xxx aluminum alloys and wrought aluminum alloy products made therefrom
JPWO2008123184A1 (en) 7000 series aluminum alloy extruded material and method for producing the same
JP7044863B2 (en) Al-Mg-Si based aluminum alloy material
JPH0372147B2 (en)
CN115053008A (en) Method for manufacturing high-strength aluminum alloy extruded material
US20230175103A1 (en) New 6xxx aluminum alloys and methods for producing the same
JPH0718390A (en) Production of aluminum alloy sheet material for forming
WO2022229800A1 (en) Aluminum casting alloy for near net shaped casting of structural or non-structural components
JPH06240424A (en) Production of aluminum alloy sheet excellent in formability and baking hardenability
JP2000212673A (en) Aluminum alloy sheet for aircraft stringer excellent in stress corrosion cracking resistance and its production
US4140556A (en) Aluminum alloy sheet
KR101499096B1 (en) Aluminum alloy and manufacturing method thereof
EP4083242A1 (en) Aluminum casting alloy for near net shaped casting of structural or non-structural components
JPH05112840A (en) Baking hardenability al-mg-si alloy sheet excellent in press formability and its manufacture
JPS6050864B2 (en) Aluminum alloy material for forming with excellent bending workability and its manufacturing method
JP3210419B2 (en) Aluminum alloy sheet for DI can excellent in flange formability and method for producing the same
JPH08176764A (en) Production of aluminum alloy sheet for forming
JPS602644A (en) Aluminum alloy
JPH10259464A (en) Production of aluminum alloy sheet for forming
JP2004124175A (en) Method for manufacturing 6000 system alloy plate for forming excellent in formability, baking hardenability, and springback characteristic
JPH11350058A (en) Aluminum alloy sheet excellent in formability and baking hardenability and its production
JPH08269608A (en) High strength aluminum alloy excellent in formability and corrosion resistance
CN117280057A (en) Cast aluminum alloy for near net shape casting of structural or non-structural members
JPH073409A (en) Heat treatment for extruded billet of al-mg-si based aluminum alloy

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22720058

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 18288467

Country of ref document: US

WWE Wipo information: entry into national phase

Ref document number: 202280031534.3

Country of ref document: CN

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 22720058

Country of ref document: EP

Kind code of ref document: A1