EP0156995B1 - Alliage aluminium-lithium - Google Patents

Alliage aluminium-lithium Download PDF

Info

Publication number
EP0156995B1
EP0156995B1 EP19840115928 EP84115928A EP0156995B1 EP 0156995 B1 EP0156995 B1 EP 0156995B1 EP 19840115928 EP19840115928 EP 19840115928 EP 84115928 A EP84115928 A EP 84115928A EP 0156995 B1 EP0156995 B1 EP 0156995B1
Authority
EP
European Patent Office
Prior art keywords
alloy
present
aged
article
percent
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
Application number
EP19840115928
Other languages
German (de)
English (en)
Other versions
EP0156995A1 (fr
Inventor
Hari G. Narayanan
Eugene R. Curtis
William E. Quist
Michael V. Hyatt
Sven E. Axter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Howmet Aerospace Inc
Original Assignee
Aluminum Company of America
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
Application filed by Aluminum Company of America filed Critical Aluminum Company of America
Publication of EP0156995A1 publication Critical patent/EP0156995A1/fr
Application granted granted Critical
Publication of EP0156995B1 publication Critical patent/EP0156995B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • 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
    • C22C21/12—Alloys based on aluminium with copper as the next major constituent
    • 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

  • the present invention relates to a process of manufacturing products from an aluminium alloy having lithium together with copper as main alloying elements. Its object is particularly to provide products of high fracture toughness and high strength that may be used in the aircraft industry.
  • aluminium-lithium alloys have been used only sparsely in aircraft structure. Their relatively low use has been caused by casting difficulties associated with aluminium-lithium alloys and by their relatively low fracture toughness compared to other more conventional aluminium alloys. Aluminium-lithium alloys, however, provide a substantial lowering of the density of aluminium alloys (as well as a relatively high strength to weight ratio), which has found to be very important in decreasing the overall weight of structural materials used in an aircraft. While substantial strides have been made in improving the aluminium-lithium processing technology, a major challenge is still to obtain a good blend of fracture toughness and high strength in an aluminium-lithium alloy.
  • the invention thus provides a process of manufacturing products from an aluminium alloy having lithium together with copper and the grain refiner zirconium as obligatory alloying elements, which process comprises the steps of: - preparing an alloy of the following composition: Element Amount (wt%) Li 2.0 to 2.4 Mg 0 to 0.9 Cu 2.3 to 2.7 Zr 0.12 max Fe plus Si 0.30 max Other Trace elements 0.25 max Al Balance - casting the alloy into an ingot, - homogenising the ingot, - forming articles from said alloy, - subjecting the articles to a solution heat treatment and a quenching step, - and aging the alloy in such articles.
  • the alloy has a nominal composition of 2.2 percent Li, 0.5 percent Mg, 2.5 percent Cu and 0.12 percent Zr, with the balance being Al and trace elements.
  • An aluminium-lithium alloy formulated in accordance with the present invention will contain 2.0 to 2.4 percent lithium, 0 to 0.9 percent magnesium, 2.3 to 2.7 percent copper and a maximum of 0.12 percent zirconium as a grain refiner. Preferably, from 0.10 to 0.12 percent zirconium is incorporated. All percentages herein are by weight based on the total weight of the alloy unless otherwise indicated. While no magnesium need be employed in the alloy, it is preferred that magnesium be included to increase strength without increasing density. Magnesium also provides solid solution strengthening. Preferred amounts of magnesium range from 0.5 to 0.9 percent, with 0.7 percent being more preferred. The copper adds strength to the alloy.
  • Iron and silicon can be present only in trace amounts, limiting the iron to a maximum of 0.15 percent and the silicon to a maximum of 0.12 percent, and preferably limiting them to maximums of 0.10 and 0.10 percent respectively.
  • Certain trace elements such as zinc, may be present in amounts up to but not exceeding 0.25 percent of the total.
  • Other elements such as chromium and manganese must be held to levels of 0.05 percent or below. If these maximums are exceeded, the desired properties of the aluminium-lithium alloy will tend to deteriorate.
  • the trace elements sodium and hydrogen are also thought to be harmful to the properties (fracture toughness in particular) of aluminium-lithium alloys and should be held to the lowest levels practically attainable, for example on the order of 15-30 ppm (0.0015-0.0030 wt.%) for the sodium and less than 15 ppm (0.0015 wt.%) and preferably less than 1.0 ppm (0.0001 wt.%) for the hydrogen.
  • the balance of the alloy comprises aluminium.
  • An aluminium-lithium alloy formulated in the proportions said forth in the forgoing paragraph is processed into an article utilizing known techniques.
  • the alloy is formulated in molten form and cast into an ingot.
  • the ingot is then homogenized at temperatures ranging from 496°C to 538°C.
  • the alloy is converted into a usable article by conventional mechanical formation techniques such as rolling, extrusion or the like.
  • the alloy is normally subjected to a solution treatment at temperatures ranging from 510°C to 538°C, quenched in a quenching medium such as water that is maintained at a temperature on the order of 21°C to 66°C. If the alloy has been rolled or extruded, it is generally stretched on the order of 1 to 3 percent of its original length to relieve internal stresses.
  • the aluminium alloy can then be further worked and formed into the various shapes for its final application. Additional heat treatments such as solution heat treatment can be employed if desired.
  • an extruded product after being cut to desired length is generally solution heat treated at temperatures on the order of 524°C for 1 to 4 hours.
  • the product is then quenched in a quenching medium held at temperatures ranging from about 21°C to 66°C.
  • the article is subjected to an aging treatment at relatively low temperatures on the order of from 93°C to 149°C. Since this alloy is intended to replace conventional 7XXX-series type alloys, it is preferred that the alloy be aged for a period of time that will allow it to achieve at least about 95% of its peak strength. It is preferred that the alloy be aged for a period of time allowing it to achieve 95-97% of its peak strength.
  • Preferred aging temperatures range from 121°C to 135°C. Within these temperature ranges, 95-97% peak strength can be achieved by aging from about 4 to 120 hours.
  • An aluminium alloy containing 2.2 percent lithium, 0.5 percent magnesium, 2.5 percent copper, 0.1 percent zirconium with the balance being aluminium was formulated.
  • the trace elements present in the formulation constituted less than 0.25 percent of the total.
  • the iron and silicon present in the formulation constituted less than 0.07 percent of the formulation.
  • the alloy was cast and homogenized at about 524°C. Thereafter, the alloy was hot rolled to a thickness of 0.5 cm. The resulting sheet was then solution treated at about 524°C for about 1 hour. It was then quenched in water maintained at about 21°C. Thereafter, the sheet was subjected to a stretch of 1.5 percent of its initial length. The material was then cut into specimens.
  • the specimens were cut to a size of 1.27 cm by 6.35 cm by 0.5 cm for the precrack Charpy impact tests, which measure fracture toughness.
  • the specimens prepared for the tensile strength tests were 2.54 cm by 10.2 cm by 0.5 cm.
  • a plurality of specimens were then aged for 120 hours at 135°C.
  • Each of the specimens aged at each of the temperatures and times were then subjected to the tensile strength and precrack Charpy impact tests in accordance with standard ASTM testing procedures.
  • the specimens underaged at 135°C exhibit an ultimate strength ranging from about 586 MPa to about 655 MPa with a toughness on the order of 0.039 J/mm2 to 0.049 J/mm2.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Powder Metallurgy (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)

Claims (14)

  1. Procédé de fabrication de produits à partir d'un alliage d'aluminium comprenant du lithium et du cuivre et le zirconium affineur de grains, en tant qu'éléments d'alliage obligatoires, ledit procédé comprenant les étapes consistant à:
    a) préparer un alliage ayant la composition suivante : Eléments Quantité (% en poids) Li 2,0 à 2,4 Mg 0 à 0,9 Cu 2,3 à 2,7 Zr jusqu'à un maximum de 0,12 Fe plus Si, au maximum 0,30 Autres éléments trace, au maximum 0,25 Al le reste
    b) mouler l'alliage en un lingot;
    c) homogénéiser le lingot;
    d) former un objet;
    e) soumettre l'objet à un traitement à la chaleur en solution;
    f) tremper l'article dans un milieu de trempe ; et
    g) faire vieillir l'objet.
  2. Procédé selon la revendication 1, dans lequel le magnésium est présent en une quantité comprise dans l'intervalle de 0,5 à 0,9 % en poids.
  3. Procédé selon la revendication 1 ou 2, dans lequel le magnésium est présent à raison de 0,7 % en poids.
  4. Procédé selon les revendications 1 à 3, dans lequel le fer est présent en des quantités allant jusqu'à 0,15 % en poids.
  5. Procédé selon les revendications 1 à 4, dans lequel le fer est présent en des quantités allant jusqu'à 0,10 % en poids.
  6. Procédé selon les revendications 1 à 5, dans lequel le silicium est présent en des quantités allant jusqu'à 0,12 % en poids.
  7. Procédé selon les revendications 1 à 6, dans lequel le silicium est présent en des quantités allant jusqu'à 0,10 % en poids.
  8. Procédé selon les revendications 1 à 7, dans lequel l'alliage a une composition nominale de 2,2 % en poids de Li, 0,5 % en poids de Mg, 2,5 % en poids de Cu et 0,12 % en poids de Zr, le reste étant constitué de Al et d'éléments trace.
  9. Procédé selon les revendications 1 à 8, dans lequel on fait vieillir l'alliage pendant une durée suffisante pour atteindre au moins 95 % de sa résistance maximale.
  10. Procédé selon les revendications 1 à 9, dans lequel on fait vieillir l'alliage pendant une durée suffisante pour atteindre de 95 à 97 % de sa résistance maximale.
  11. Procédé selon les revendications 1 à 10, dans lequel on fait vieillir l'objet à une température comprise dans l'intervalle de 93°C (200°F) à 149°C (300°F).
  12. Procédé selon la revendication 11, dans lequel on fait vieillir l'alliage à une température comprise dans l'intervalle de 121°C (250°F) à 135°C (275°F).
  13. Procédé selon les revendications 1 à 12, dans lequel on fait vieillir l'alliage pendant une durée comprise dans l'intervalle de 4 à 120 h.
  14. Procédé selon la revendication 1, dans lequel le zirconium est présent à raison de 0,10 à 0,12 % en poids.
EP19840115928 1983-12-30 1984-12-20 Alliage aluminium-lithium Expired - Lifetime EP0156995B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US56735683A 1983-12-30 1983-12-30
US567356 1983-12-30

Publications (2)

Publication Number Publication Date
EP0156995A1 EP0156995A1 (fr) 1985-10-09
EP0156995B1 true EP0156995B1 (fr) 1994-09-28

Family

ID=24266811

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19840115928 Expired - Lifetime EP0156995B1 (fr) 1983-12-30 1984-12-20 Alliage aluminium-lithium

Country Status (3)

Country Link
EP (1) EP0156995B1 (fr)
JP (1) JPS60211035A (fr)
DE (1) DE3486352T2 (fr)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2561260B1 (fr) * 1984-03-15 1992-07-17 Cegedur Alliages al-cu-li-mg a tres haute resistance mecanique specifique
US5137686A (en) * 1988-01-28 1992-08-11 Aluminum Company Of America Aluminum-lithium alloys
US4961792A (en) * 1984-12-24 1990-10-09 Aluminum Company Of America Aluminum-lithium alloys having improved corrosion resistance containing Mg and Zn
JPS61166938A (ja) * 1985-01-16 1986-07-28 Kobe Steel Ltd 展伸用Ａｌ−Ｌｉ系合金およびその製造方法
DE3613224A1 (de) * 1985-08-20 1987-02-26 Boeing Co Aluminium-lithium-legierung
EP0250656A1 (fr) * 1986-07-03 1988-01-07 The Boeing Company Sous-vieillissement à basse température d'alliages contenant du lithium
US5108519A (en) * 1988-01-28 1992-04-28 Aluminum Company Of America Aluminum-lithium alloys suitable for forgings
US5066342A (en) * 1988-01-28 1991-11-19 Aluminum Company Of America Aluminum-lithium alloys and method of making the same
US4869870A (en) * 1988-03-24 1989-09-26 Aluminum Company Of America Aluminum-lithium alloys with hafnium
JP4775911B2 (ja) * 2007-06-28 2011-09-21 株式会社アルバック アルミニウム−リチウム合金ターゲットの製造方法およびアルミニウム−リチウム合金ターゲット

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB787665A (en) * 1955-04-05 1957-12-11 Stone & Company Charlton Ltd J Improvements relating to aluminium-base alloys

Also Published As

Publication number Publication date
DE3486352D1 (de) 1994-11-03
DE3486352T2 (de) 1995-04-20
JPS60211035A (ja) 1985-10-23
EP0156995A1 (fr) 1985-10-09

Similar Documents

Publication Publication Date Title
EP0546103B1 (fr) Systeme d'alliage de lithium et d'aluminium ameliore
EP0157600B1 (fr) Alliages aluminium-lithium
EP2049696B1 (fr) Alliage d'aluminium à haute résistance pouvant être traité thermiquement
EP0584271B1 (fr) ALLIAGE DE Al-Li A RESISTANCE ELEVEE ET A FAIBLE DENSITE
EP0150456B1 (fr) Vieillissement à température relativement basse d'un alliage d'aluminium, contenant du lithium
EP2558564B1 (fr) Alliages d'aluminium lithium de série 2xxx à faible différentiel de résistance
EP0656956B2 (fr) Alliage d'aluminium resistant contenant du cuivre et du magnesium
US20070258847A1 (en) NEW Al-Cu-Li-Mg-Ag-Mn-Zr ALLOY FOR USE AS STRUCTURAL MEMBERS REQUIRING HIGH STRENGTH AND HIGH FRACTURE TOUGHNESS
US20030226623A1 (en) Method for the manufacturing of an aluminium-magnesium-lithium alloy product
US5389165A (en) Low density, high strength Al-Li alloy having high toughness at elevated temperatures
EP3521467B1 (fr) Alliage de plaque d'aluminium-lithium à faible densité, à faible coût, essentiellement exempt d'ag et de zn, pour application aérospatiale
US4603029A (en) Aluminum-lithium alloy
EP0149193B1 (fr) Alliage aluminium-lithium
US4795502A (en) Aluminum-lithium alloy products and method of making the same
EP0156995B1 (fr) Alliage aluminium-lithium
KR100540234B1 (ko) 알루미늄 기초 합금 및 알루미늄 기초 합금의 열처리 방법
CA2440787A1 (fr) Extrusions d'alliage d'aluminium presentant une structure sensiblement non recristallisee
JP3540316B2 (ja) アルミニウム−リチウム合金の機械的特性の改良
EP0214381B1 (fr) Alliage aluminium-lithium
US4999061A (en) Low temperature underaging of lithium bearing alloys and method thereof
EP0151301B1 (fr) Alliage aluminium-lithium
EP0266741B1 (fr) Alliages à base d'aluminium-lithium et procédé de production
US5133930A (en) Aluminum-lithium alloy
US5160555A (en) Aluminum-lithium alloy article
EP0250656A1 (fr) Sous-vieillissement à basse température d'alliages contenant du lithium

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE FR GB IT NL

17P Request for examination filed

Effective date: 19860307

17Q First examination report despatched

Effective date: 19861106

R17C First examination report despatched (corrected)

Effective date: 19861124

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: ALUMINUM COMPANY OF AMERICA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT NL

REF Corresponds to:

Ref document number: 3486352

Country of ref document: DE

Date of ref document: 19941103

ITF It: translation for a ep patent filed

Owner name: STUDIO TORTA SOCIETA' SEMPLICE

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20000929

Year of fee payment: 17

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20001107

Year of fee payment: 17

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20001204

Year of fee payment: 17

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20001222

Year of fee payment: 17

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20011220

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20020701

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20020702

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20011220

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20020830

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 20020701

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

APAH Appeal reference modified

Free format text: ORIGINAL CODE: EPIDOSCREFNO