SI25352A - Production of high-strength and temperature resistant aluminum alloys fortified with double excretion - Google Patents
Production of high-strength and temperature resistant aluminum alloys fortified with double excretion Download PDFInfo
- Publication number
- SI25352A SI25352A SI201700256A SI201700256A SI25352A SI 25352 A SI25352 A SI 25352A SI 201700256 A SI201700256 A SI 201700256A SI 201700256 A SI201700256 A SI 201700256A SI 25352 A SI25352 A SI 25352A
- Authority
- SI
- Slovenia
- Prior art keywords
- aging
- weight
- temperature
- alloys
- strength
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
-
- 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
-
- 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
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/002—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working by rapid cooling or quenching; cooling agents used therefor
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
- C22F1/057—Changing 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 copper as the next major constituent
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Continuous Casting (AREA)
- Forging (AREA)
- Powder Metallurgy (AREA)
Abstract
Izum izdelava visokotrdnostnih in temperaturnoobstojnih aluminijevih zlitin utrjenih z dvojnimi izločki, se nanaša na visokotrdnostne in temperaturnoobstojne aluminijeve zlitine in postopek njihove izdelave. Zlitine vsebuje 2,0-5,0 mas.% Mn; 0,001-2,0 mas.% Cr; 2,0-5,0 mas.% Cr + Mn; 0,001-0,5 mas.% V; 2,0-4,5 mas.% Cu; 0,001-0,9 mas.% Be; 0,05-0,5 mas.% Sc; in ki vsebujejo vsaj še enega izmed elementov Zr, Y, Ti, Hf in Nb v deležu 0,001-0,4 mas.%; preostalo je aluminij in neizogibne nečistoče do največ 0,5 mas.%. Zlitine se ulijejo, pri čemer je hitrost ohlajevanja vsaj 100 K/s. Zlitine se lahko pred staranjem plastično deformirajo. Nato se starajo prvič pri prvi temperaturi staranja za prvi čas staranja. Zatem se starajo drugič pri drugi temperaturi staranja v trajanju drugega časa staranja, da dosežemo kombinacijo ikozaedričnih in L12-izločkov. Zlitine se lahko tretjič starajo pri tretji temperaturi in tretjem času staranja, pri čemer jih je treba pred tem hitro ohladiti z druge temperature staranja.The invention provides the manufacture of high-strength and temperature-resistant aluminum alloys fortified with double excretions, refers to high-strength and temperature-resistant aluminum alloys and the process of their manufacture. Alloys contain 2.0-5.0% by weight of Mn; 0.001 to 2.0% by weight of Cr; 2.0-5.0 wt% Cr + Mn; 0.001-0.5% by weight V; 2.0-4.5 wt% Cu; 0.001 to 0.9% by weight Be; 0.05-0.5% by weight Sc; and which contain at least one of the elements Zr, Y, Ti, Hf and Nb in a proportion of 0.001 to 0.4% by weight; the remaining aluminum and inevitable impurities up to a maximum of 0.5% by weight. The alloys are poured, the cooling rate being at least 100 K / s. Alloys can be plastic deformed before aging. They are then aged for the first time at the first aging temperature for the first aging time. They are then aged at a second aging temperature for the second aging time to achieve a combination of ikozaedric and L12 excretions. Alloys can be aged for the third time at a third temperature and a third time of aging, and they must be quickly cooled from the second aging temperature.
Description
OPIS IZUMA
Izdelava visokotrdnostnih in temperaturnoobstoinih aluminijevih zlitin, utrjenih z dvojnimi izločki
Področje izuma
Izum spada na področje metalurgije neželeznih kovin, bolj natančno na področji livarstva in toplotne obdelave aluminijevih zlitin.
Prikaz problema
Za aluminij in aluminijeve zlitine je značilno, da imajo majhno gostoto, veliko specifično trdnost (trdnost na enoto gostote) in konkurenčno korozijsko odpornost. Deli iz aluminija se lahko gospodarno izdelajo z raznovrstnimi izdelovalnimi postopki. Gnetne zlitine lahko dosežejo ob utrjevanju s standardnimi utrjevalnimi mehanizmi mejne vrednosti natezne trdnosti med 550 MPa in 600 MPa, vendar ob zmanjšani razteznosti (okoli 10 %). Zlitine Al-Si, ki so legirane z različnimi zlitinskimi elementi (npr. AISi12CuNiMg), lahko dosežejo natezne trdnosti do 400 MPa, medtem ko so razteznosti do 5 %.
Večina visokotrdnostnih aluminijevih zlitin se utrdi z izločevalnim utijanjem. Najbolj pogosta toplotna obdelava je označena s T6. Toplotna obdelava T6 je sestavljena iz topilnega žaljenja, ki poteka na temperaturo solvus zlitine. Pri topilnem žarjenju se poveča homogenost zlitine, zlitinski elementi, ki tvorijo izločke pa prehajajo iz različnih intermetalnih faz v trdno raztopino na osnovi aluminija. Zatem se zlitina hitro ohladi (gasi). Ohlajevalna hitrost mora biti dovolj velika, da ostanejo v trdni raztopini skoraj vsi raztopljeni zlitinski elementi. Med naravnim staranjem (na sobni temperaturi) ali umetnim staranjem (pri povišanih temperaturah, praviloma pod 200 °C) nastajajo v trdni raztopini izločki, ki utijujejo aluminijevo zlitino.
Toplotna obdelava T5 je alternativa za obdelavo T6. Pri tej toplotni obdelavi se zlitina neposredno segreje s sobne temperature na temperaturo umetnega staranja, ne da bi zlitino vmes topilno žarili in starali. Osnovni pogoj za to je, da se npr. pri litju, dosežejo dovolj velike ohlajevalne hitrosti, da zadosti velik delež zlitinskih elementov ostane v trdni raztopini. Izločki nastanejo med neposrednim umetnim staranjem.
Pri obeh toplotnih obdelavah, T5 in T6, izločki utrjujejo zlitino le pri nižjih temperaturah. Ko se temperatura približuje 200 °C, se začnejo postajati bolj grobi ter se raztapljati. To vodi k sunkovitemu zmanjšanju trdnostnih lastnosti.
Za napredne aplikacije je treba aluminijeve zlitine izdelati v različnih oblikah, morajo pa imeti tudi ustrezno kombinacijo majhne gostote, velike trdnosti pri sobni temperaturi, toplotne obstojnosti in konkurenčne cene. V znanstveni literaturi in patentih obstaja več rešitev za rešitev zgornjega problema, ki so že bile uporabljene v industrijski praksi ter so relevantne za ta primer.
Pri visokotrdnostnih in temperaturnoobstojnih izločevalnoutrjevalnih zlitinah brez Sc se temperaturna obstojnost konča že pri temperaturah tik nad 200 °C, ker se izločki ogrobijo ali celo raztopijo. Izločevalnoutrjevalne zlitine imajo boljšo temperaturno obstojnost, vendar so dražje, ker vsebujejo Sc. Delež skandija je sorazmerno velik, zato zaradi omejenih zalog Sc ni mogoče izdelovati zlitin v velikih količinah. Zlitine, utrjene samo s kvazikristali, se lahko izdelajo samo s hitrim strjevanjem, zato je njihova uporabnost omejena.
Podati« o stanju tehnike a) Visokotrdnostne in temperatumoobstoine izločevalnoutrjevalne zlitine brez Sc
Visokotrdnostne aluminijeve zlitine izvirajo iz izločevalnoutrjevalnih zlitin iz zlitinskih sistemov Al-Cu (serija AA2xxx), Al-Si-Mg (serija AA6xxx), Al-Li in Al-Zn-Mg (serija AA7xxx). Zlitine lahko izdelamo z različnimi postopki (litje, metalurgija prahov, preoblikovanje) in jih kasneje toplotno obdelamo pretežno s toplotnima obdelavama T6 in T5. Povečana toplotna obstojnost se doseže z dodatki elementov, kot so Mn, Cr, Zr, Nb, Hf ali V, ki lahko tvorijo različne vrste izločkov, ki so manj topni v aluminijevi osnovi kot običajni izločki, in lahko ostanejo v zlitini tudi pri povišanih temperaturah.
Patent WO 2002063059 A1 razkriva dvostopenjski proces staranja delov, ki so narejeni iz zlitine, ki vsebuje vsaj aluminij in baker. Patent WO 2008003503 A2 prestavlja metodo izdelave zlitin AA2xxx za gnetenje, ki imajo sorazmerno velike mere. V obeh zlitinah se med toplotno obdelavo tvorijo izločki Al-Cu, ki ne morejo vzdržati temperatur višjih od 200 °C.
Patent US 5759302 A opisuje sestave zlitine iz sistemov Al-Cu in Al-Zn-Mg, ki so legirani z Mn, Cr or Zr, in toplotno obdelani tako, da nastanejo disperzoidi iz sistemov Al-Mn, Al-Cr ali Al-Zr, ki prispevajo k povečani zlomni žilavosti, odpornosti proti utrujanju in preoblikovalnosti.
Patent US 20170051383 A1 opredeljuje sestavo zlitine in parametre tristopenjskega staranja, da bi dobili dvojne izločke v aluminijevi osnovi, ki bi zagotovili uporabo izumljenih zlitin pri visokotemperaturnih aplikacijah. Zlitina je legirana s Cu in Zr, ter prav tako z Nb, Hf ali V.
Patent US 5226983 A definira zlitine Al-Zr-Li-X, ki se izdelajo s hitrim strjevanjem. Po njem se zlitina po topilnem žarjenju večkrat umetno stara. Mikrostruktura je sestavljena iz aluminijeve osnove in izločkov AI3(Zr, Li).
Patent WO 2011122958 A1 optimira zlitino Al-Mg-Si-Cu za visokotemperaturno stabilnost. Definira kemijsko sestavo zlitine. Cilj je doseči L-fazo kot dominantno vrsto izločka v prestaranem stanju glede na številko gostoto izločkov.
Patent US 6074498 A definira zlitine Al-Cu-Li-Sc, ki jih izpostavimo dvojnemu staranju. Namen je doseči izločke T1 znotraj aluminijevih zrn, medtem ko je na kristalnih mejah območje brez izločkov T1. Po drugi strani nastanejo bolj grobi izločki θ' and č' tako znotraj kristalnih zrn kot tudi ob in na kristalnih mejah. b) Visokotrdnostne in temperaturnoobstojne aluminijeve zlitine, ki vsebuje Sc in izločke L12
Izločki L12 imajo urejeno kubično kristalno zgradbo s splošno formulo ΑΙ3Χ, kjer X predstavlja enega ali več elementov, med katerimi so najpomembnejši Sc, Zr in Y. Izločki I_12 so koherentni z aluminijem bogato osnovo. Nastajajo med toplotno obdelavo in so precej stabilni pri povišanih temperaturah. V tabeli 1 je spisek patentov za aluminijeve zlitine, ki vsebujejo izločke Li2. Patenti razkrivajo kemijsko sestavo zlitin, postopke njihove izdelave (npr. litje, hitro stijevanje, valjanje, varjenje, iztiskanje), kakor tudi njihovo toplotno obdelavo.
Patent US 6248453 B1 razkriva aluminijeve zlitine, ki vsebujejo Sc, Er, Lu, Yb, Trn in U ter tudi vsaj enega izmed elementov iz Mg, Ag, Zn, Li in Cu. Zlitine se izdelajo s hitrim strjevanjem ter so sestavljene iz aluminijeve osnove z izločki AI3X, ki imajo kristalno zgradbo Ι_ι2.
Obstaja več patentov z naslovom »Visokotrdnostne aluminijev zlitine L12« (originalno “High strength L12 aluminium alloys”; glej Tabelo 1). Patenti razkrivajo več osnovnih sestav zlitin, ki so jim dodani elementi skandij, erbij, tulij, iterbij in lutecij, zraven pa še vsaj eden izmed elementov gadolinij, itrij, cirkonij, titan, hafnij ali niobij. Ena izmed možnih sestav je AI-(1-8)Cu-(0.2-4)Mg-(0.1-0.5)Sc-(0.05-1.0)Zr (US 7909947). V drugih patentih so različne sestave osnovnih zlitin [v US 8002912 B2 je osnovna zlitina AI-(4-25)Ni-(0,1-15)Tm (Trn je prehodna kovina), in v US 7871477 B2 je osnovna zlitina AI-(3-6)Mg-(0,5-3)Li]. V vseh primerih je mikrostruktura zlitine po toplotni obdelavi sestavljena iz aluminijeve osnove in izločkov L12.
Patent US 5620652 A definira aluminijev zlitine, ki vsebujejo Sc, ter imajo še dodan Zr. Uporabljajo se lahko za športne produkte, kopenski transport, strukture za pomorstvo, letalstvo in vesoljsko tehniko. Patent ne podaja podrobnosti toplotne obdelave. Predpostavljamo, da imajo zlitine aluminijevo osnovo in izločke ΑΙ3Χ s kristalno zgradbo Li2.
Patent US 20100143185 A1 predstavlja metodo izdelave visokotrdnostnih aluminijevih zlitin, ki vsebujejo izločke l_12. Prah zlitine se izdela z atomizacijo taline. Sestava zlitine, definirana z izumom, zagotovi, da v prahu zlitine nastanejo izločki L12, ki so enakomerno razporejeni v aluminijevi osnovi.
Belov in sodelavci [1] so razvili zlitino Al-Cu-Mn-Zr-Sc, ki ne potrebuje topilnega žaljenja in gašenja, da bi se dosegla visoka trdnost. Zlitina vsebuje po toplotni obdelavi izločke L12, vendar pa ne ikozaedričnih kvazikristalnih izločkov (IQC). Namesto izločkov IQC se tvorijo izločki AI20Mn3Cu2. Njihova slabost je v tem, da nastajajo v obliki palic in ne krogel. Poleg tega je številska gostota teh izločkov bistveno manjša kot izločkov IQC, ki imajo kroglasto obliko.
[1] N.A. Belov, A.N. Alabin, I.A. Matveeva, Optimization of phase composition of Al-Cu-Mn-Zr-Sc alloys for rolled products vvithout requirement for solution treatment and guenching, J. Alloy. Compd., 583 (2014) 206-213.
Tabela 1: Spisek patentov za aluminijeve zlitine, ki vsebujejo izločke L12
c) Aluminijeve zlitine utrjene s kvazikristali
Kvazikristali so kristali, ki imajo urejenost dolgega dosega, vendar niso periodični. To je glavna razlika s periodičnimi kristali. Aluminijeve zlitine utrjene s kvazikristali ima periodično aluminijevo osnovo, v kateri je dispergirana kvazikristalna faza. Kvazikristalna faza lahko nastane med hitrim strjevanjem in litjem, lahko pa jo dodamu aluminiju z metodami, ki so običajne pri izdelavi kompozitov. Pri izdelavi kompozitov se lahko kvazikristalni delci dodajo v aluminijevo talino; dele potem oblikujemo z litjem. Kvazikristalni prah se lahko primeša k aluminijevemu prahu, deli pa se izdelajo s postopki metalurgije prahov.
Patent US 5593515 A razkriva izdelavo zlitine, ki ima splošno formulo Ali,aiQaMtoXcTd. Pri tem Q predstavlja vsaj enegi izmed elementov Mn, Cr, V, Mo in W; M predstavlja vsaj enega izmed elementov Co, Ni, Cu in Fe; medtem ko X označuje Y ali Mm (Mischmetal; zlitina, ki vsebuje več elementov redkih zemelj); T označuje vsaj enega izmed elementov iz skupine Ti, Zr and Hf; indeksi a, b, c in d pa označujejo vsebnosti elementov v atomskih odstotkih: 1 ^a^7, 0>5, 0>c^ 5 in 0 > d i 2. Zlitina ima odlično trdoto in trdnost tako pri nizkih kot tudi pri povišanih temperaturah, ter odlično toplotno upornost in duktilnost. Produkti se lahko izdelajo s hitrim stijevanjem, toplotno obdelavo delov, izdelanih s hitrim strjevanjem, ali s konsolidacijo zlitine, izdelane s hitrim strjevanjem.
Patent US 5419789 A odkriva aluminijeve zlitine, ki vsebujejo Al in vsaj dva prehodna elementa v atomskih deležih med 0,1 % in 25 %, v katerih so kvazikristalni delci enakomerno razporejeni v aluminijevi osnovi. Produkti se lahko izdelajo s hitrim strjevanjem, toplotno obdelavo delov, izdelanih s hitrim strjevanjem, ali s konsolidacijo zlitine, izdelane s hitrim strjevanjem.
Schurack in sodelavci [2, 3] so želeli izboljšati lastnosti aluminijevih zlitin z utrjanjem s kvazikristali. Zlitine so izdelali s hitrim strjevanjem na vrtečem kolesu (ang. melt spinning), mehanskim legiranjem in litjem. Poročali so, mehansko legiranje stabilnih kvazikristalov AICuFe in aluminijevega prahu ni zagotovilo ustrezne kombinacije trdnosti in duktilnosti. Dodatek Ce zlitinam Al-Mn je povečal težnjo k nastanku kvazikristalov, verjetno s stabilizacijo kvazikristalne zgradbe v talini. To je omogočilo neposreden nastanek kvazikristalov pri ohlajanju taline. Mleti in iztisnjeni trakovi hitro stijene zlitine AI92Mn6Ce2 so dosegli trdnost okoli 800 MPa in razteznost ~25 %, medtem ko so konvencionalno lite palice imele natezno trdnost okoli 500 MPa in razteznost ~20 %.
Song in sodelavci [4] so ugotovili, da dodatek Be izrazito zmanjša kritično ohlajevalno hitrost za nastanek kvazikristalov pri strjevanju ter minimalni dodatek Mn. V njihovih zlitinah so kvazikristali nastali pri klasičnih postopkih litja (npr. pri tlačnem litju). Toda njihove zlitine so poleg kvazikristalov vsebovale še druge intermetalne faze, ki neugodno vplivajo na trdnostne lastnosti. Izboljša zlitine so pripravili Rozman in sodelavci [5].
[2] F. Schurack, J. Eckert, L. Schultz: Synthesis and mechanical properties of čast quasicrystal-reinforced Al-alloys, Acta materialia, 49 (2001) 1351-1361 [3] F. Schurack, J. Eckert, L. Schultz: Synthesis and mechanical properties of quasicrystalline Al-based composites, Quasicrystals, Structure and Physical Properties, Wiley-VCH GmbH & Co. KgaA, VVeinheim, 2003, 551-569 [4] G.S. Song, E. Fleury, S.H. Kirn, W.T. Kirn, D.H. Kirn: Enhancement of the quasicrystal-forming ability in Al-based alloys by Be-addition, Journal of Alloys and Compounds, 342 (2002) 251 -255 [5] N. Rozman, J. Medved, F. Zupanič, Microstructural evolution in Al-Mn-Cu-(Be) alloys, Philos. Mag., 91 (2011) 4230-4246. d) Kvazikristalni izločki v aluminijevih zlitinah
Kirn in sodelavci [6] so odkrili dekagonalne kvazikristalne izločke v hitrostrjeni in žarenji komercialni aluminijevi zlitini AISI 2024, ki je vsebovala 2 mas. % Li. Dekagonalni kvazikristalni izločki so nastajali iz trdne raztopine pri 400 °C. Zhang in sodelavci [7, 8] so s presevno elektronsko mikroskopijo raziskovali procese pri žarjenju prenasičenih trdnih raztopin v nekaterih hitrostrjenih zlitinah aluminija z elementi prehodnih kovin. Ugotovili so, da lahko kvazikristalni izločki nastanejo v aluminijevi osnovi v binarnih Al-Cr in Al-Fe, prav tako pa tudi v sistemih Al-V, Al-Cr in Al-Mo, če vsebujejo le manjše količine Fe.
Zupanič in sodelavci [9] so odkrili ikozaedrične izločke v zlitinah Al-Mn-Be-Cu, ulitih v bakreno kokilo, ki so bile žarjene 24 uri pri 300 °C. Kinetiko in mehanizem izločanja pri 300 °C sta raziskala Bončina in Zupanič [10].
Obstaja tudi patent v zvezi s kvazikristalnim izločki (US 5632826). Toda izločki so v železovi zlitini, zato patent ni povezan s to invencijo.
[6] D.H. Kim, K. Chattopadhyay, B. Cantor, QUASI-CRYSTALLINE AND RELATED CRYSTALLINE PHASES IN A RAPIDLY SOLIDIFIED 2024-2LI ALUMINUM-ALLOY, Acta Metallurgica Et Materialia, 39 (1991) 859-875.
[7] X.D. Zhang, Y.J. Bi, M.H. Loretto, STRUCTURE AND STABILITY OF THE PRECIPITATES IN MELT SPUN TERNARY AL-TRANSITION-METAL ALLOYS, Acta Metallurgica Et Materialia, 41 (1993) 849-853.
[8] X .D. Zhang, M.H. Loretto, Stability and decomposition mechanisms of supersaturated solid Solutions in rapidly solidified aluminium transition metal alloys, Materials Science and Technology, 12 (1996) 19-24.
[9] ZUPANIČ, Franc, WANG, Di, GSPAN, Cristian, BONČINA, Tonica.
Precipitates in a quasicrystal-strengthened Al-Mn-Be-Cu alloy. Materials characterization, ISSN 1044-5803. [Print ed.j, Aug. 2015, vol. 106, str. 93-99. http://www.sciencedirect.com/science/article/pii/S1044580315001606, doi: 10.1016/j.matchar.2O15.05.013.
[10] BONČINA, Tonica, ZUPANIČ, Franc. In situ TEM study of precipitation in a quasicrystal-strengthened Al-alloy. Archives of metallurgy and materials, ISSN 1733-3490, 2017, vol. 62, iss. 1, str. 5-9. http://www.imim.pl/files/archiwum/Vol1_2017/01 .pdf, doi: 10.1515/amm-2017-0001
Opis nove rešitve
Izum Izdelava visokotrdnostnih in temperaturnoobstojnih aluminijevih zlitin, utrjenih z dvojnimi izločki je postopek izdelave visokotrdnostnih in temperaturnoobstojnih aluminijevih zlitin, ki so utrjene z dvojnimi kvazikristalnimi in Li2-izločki. Na način izdelane zlitine so primerne za uporabo v avtomobilski, vesoljski in letalski industriji, prav tako pa tudi v gradbeništvu in drugje.
Zahtevane lastnosti se lahko dosežejo z ustrezno kombinacijo kemijske sestave zlitine, strjevanja taline s katero koli metodo litja, pri kateri ohlajevalna hitrost v talini tik pred začetkom strjevanja preseže 100 K/s, ter dvo- ali tristopenjsko toplotno obdelavo (T5). Pred toplotno obdelavo se lahko ulitki še hladno ali toplo plastično deformirajo s katero koli preoblikovalno tehnologijo.
Toplotno-obdelovalna aluminijeva zlitina, ki ima veliko trdnost in toplotno obstojnost, vsebuje Mn: 2,0-5,0 mas. %;
Cr: 0,001-2,0 mas. %;
Cr + Mn: 2,0-5,0 mas. %; V: 0,001-0,5 mas. %;
Cu: 2,0-4,5 mas. %;
Be: 0,001-0,9 mas. %;
Sc: 0,05-0,5 mas. %; vsebuje še vsaj enega od naslednjih elementov Zr: 0,001-0,4 mas. %; Y: 0,001-0,4 mas. %;
Ti: 0,001-0,4 mas. %;
Hf: 0,001-0,4 mas. % in
Nb: 0,001-0,4 mas. %; preostalo je Al in neizogibne nečistoče, katerih skupna vrednost ne sme presegati 0,5 mas. %.
Zlitina, v okviru navedene sestave, je po ustreznem litju in toplotni obdelavi sestavljena iz aluminijeve osnove, v kateri so pretežno ikozaedrični kvazikristalni izločki (IQC-izločki) in izločki L12. Zlitinski elementi Mn, Cr in V so nujni, da nastane pri strjevanju kvazikristalna faza. Elementa Cr in V sta potrebna, da se pri toplotni obdelavi tvori okoli kvazikristalnih jeder bogatih z Mn lupina, ki je bogata s Cr in V. Majhna količina berilija zagotovi nastanek kvazikristalne faze pri litju, ko ohlajevalna hitrost preseže 100 K/s. Berilij prav tako pospešuje izločanje kvazikristalnih izločkov med toplotno obdelavo. Skandij in elementi iz skupine X (itrij, cirkonij, titan, hafnij in niobij) so bistveni, da se tvorijo izločki l_i2, ki imajo urejeno kristalno zgradbo. Kombinacija stroncija s katerim koli elementom iz skupine X omogoči nastanek t.i. lupinastih izločkov AbiSr, X). V teh izločkih se skandij nahaja predvsem v jedrih izločkov, medtem ko so elementi X v njihovih lupinah. Navzočnost bakra v zlitini omogoča nastanek izločkov bogatih z bakrom (Θ” ali Θ’) v aluminijevi osnovi med kvazikristalnimi in Li2-izločki pri tretji, nizkotemperaturni toplotni obdelavi, ter in-situ transformacijo kvazikristalne faze v T-fazo (AI2oMn3Cu2) pri višjih temperaturah uporabe.
Zlitina se lahko izdela v tekočem stanju s taljenjem v indukcijski ali kateri koli drugi peči. Priporočljivo je taljenje v vakuumu ali zaščitni atmosferi, da se prepreči izguba zlitinskih elementov, navodičenje in nastanek oksidov. Kot vložek lahko uporabimo tehnično čisti aluminij in predzlitine, ki so dostopne na trgu (npr. AICu50, ΑΙΥ10).
Za prehod v trdno stanje se lahko uporabi kateri koli postopek litja, pri katerem ohlajevalna hitrost presega 100 K/s. Ti postopki obsegajo, vendar niso omejeni z njimi, gravitacijsko litje v trajne kokile, visokotlačno litje, centrifugalno litje, kontinuirno litje, enovaljčno in dvovaljčno litje. Ustrezne hitrosti ohlajanja zagotovijo, (1) da kvazikristalna faza nastane predvsem na kristalnih mejah, kar med nadaljnjo toplotno obdelavo prepreči rast kristalnih zrn aluminija; in (2) da ostane ustrezna količina zlitinskih elementov raztopljena v aluminijevi osnovi, ki omogoči izločanje različnih vrsti izločkov med nadaljnjo toplotno obdelavo (modificirana toplotna obdelava T5).
Zlitina, ki je predmet tega izuma, ima ustrezno preoblikovalnost, zato se lahko pred toplotno obdelavo plastično deformira s katerim koli preoblikovalnim postopkom. Plastična deformacije poveča homogenost zlitine, razbije delce faz, ki so nastali pri strjevanju, prav tako pa lahko pospeši procese izločanja pri toplotni obdelavi. Postopek plastične deformacije je opcija.
Toplotna obdelava je sestavljena iz dveh ali treh stopenj umetnega staranja, ki predstavlja modificirano toplotno obdelavo T5.
Namen staranja pri prvi temperaturi staranja in pri prvem času staranja je doseči izjemno veliko gostoto ikozaedričnih kvazikristalov. Kvazikristal predstavlja stanje snovi, v katerih so atomi pravilno razporejeni v prostoru, vendar niso periodični. Ikozaedrični kvazikristali so kvaziperiodični v treh smereh - v prostoru. Ikozaedrični kvazikristali imajo zelo visoko stopnjo simetrije, zato pogosto rastejo v kroglasti obliki, kar je prednost v primerjavi z rastjo drugih faz v aluminijevih zlitinah, ki rastejo v obliki iglic ali ploščic. Kvaziperiodičnost omogoča odlično ujemanje ikozaedričnih kvazikristalov z aluminijevo osnovo, zato je površinska energija med fazama zelo majhna. Majhna površinska energija omogoča homogen nastanek IQC-izločkov, ki nastanejo v zelo velikem številu. Velikost IQC-izločkov je 10-15 nm, razdalja med delci pa je 30-40 nm. Mobilnost Μη-atomov določa velikost in razdaljo med delci. Zato je za staranje potrebna temperatura med 260 °C in 340 °C in čas 2-90 h. Kvazikristalni izločki vsebujejo v glavnem aluminij in mangan. Med prvim staranjem lahko nastanejo kockasti izločki AI3SC med IQC-izločki, ki so manjši kot 10 nm. Mikrostruktura po prvem staranju je sestavljena iz IQC- in AI3Sc-izločkov.
Cilj drugega staranja je narediti mikrostrukturo bolj stabilno, ko je zlitina izpostavljena povišanim temperaturam med uporabo. Temperatura drugega staranja mora biti višja kot temperatura prvega staranja. Drugo staranje se izvede v temperaturnem območju med 350 °C in 490 °C, trajanje pa je od 15 minut do 10 ur. Med drugim staranjem rastejo kvazikristalni izločki, ki so nastali med prvim staranjem, prav tako pa se ogrobijo. Med ogrobitvijo se njihovo število zmanjša. V zlitinah, ki vsebujejo Cr in V, nastane okoli jedra ikozaedričnega kristala, ki je bogat z Mn, lupina, ki je bogata s Cr in V. Ker je difuzivnost Cr in V manjša kot Mn, lupina oteži ogrobitev izločkov ob izpostavljenosti zlitine povišanim temperaturam. I_i2-izločki, bogati s skandijem (AI3Sc), rastejo naprej. V tej stopnji bodo elementi X (Zr, Y, Ti, Hf, Nb) tvorili lupino okoli s skandijem bogatega jedra L12-izločkov.
Elementi X imajo manjšo difuzivnost kot skandij. Tako bo lupina, bogate z elementi X, močno otežila ogrobitev Li2-izločkov. Mikrostruktura po drugem staranju bo vsebovala lupinaste IQC-izločke, ki so veliki 20-50 nm, in lupinaste izločke L12, ki so veliki 10-20 nm in so enakomerno razporejeni v prostoru med IQC-izločki. Takšna mikrostruktura je zelo stabilna do temperatur, ki so blizu temperaturam drugega staranja (največ 450 °C).
Tretje staranje je opcija. Njegov namen je, da se iz trdne raztopine, v prostorih med IQC- in I_i2-izločki, izločijo še z bakrom bogati izločki. Zahteva se, da se zlitina gasi v vodi s temperature drugega staranja in potem segreje na temperaturo tretjega staranja, ki je med 120 °C in 190 °C. Trajanje tretjega staranja je 2-16 ur. Vsebnost bakra v IQC- in Li2-izločkih je zelo majhna, zato ostane Cu pri temperaturi drugega staranja skoraj v celoti v trdni raztopini. Z gašenjem s temperature drugega staranja se zadrži v trdni raztopini. Pri segretju na temperaturo tretjega staranja se izloči v obliki z bakrom bogatih izločkov: Θ’ in Θ”. S tem se zlitini poveča trdnost pri nizkih temperaturah. Temperaturna obstojnost pa se ne spremeni, ker se ti izločki pri temperaturah nad 200 °C ponovno raztopijo v osnovi.
Pomembna prednost te metode je, da lahko dosežemo s postopki litja, ki so uveljavljeni v livarnah aluminija, ustrezne oblike ulitkov in želeno začetno mikrostruktura, ki omogoča uspešno toplotno obdelavo. Vsebnosti zlitinskih elementov so sorazmerno majhne. Tako lahko tudi ulitke po potrebi plastično deformiramo, ker imajo ustrezno duktilnost. Količine zlitinskih elementov, predvsem tistih z visoko ceno (npr. skandija), so majhne. Tako je strošek na enoto lastnosti tudi majhen. To je pomembno v povezavi z aluminijevimi zlitinami, ki so legirane s skandijem (npr. patent EP 2598664 B1). Ikozeadrični in IQC-izločki so koherentni z aluminijevo osnovo, zato lahko nastanejo v mnogo večjih številskih gostotah kot disperzoidi. Tako izumljene zlitine dajejo dosti več možnosti za doseganje lastnosti kot s toplotno obdelavo in plastično deformacijo.
Primer izuma “Izdelava visokotrdnostnih in temperaturnoobstoinih aluminijevih zlitin, utrjenih z dvojnimi izločki«
Kemijska sestava zlitine je bila:
Zlitina je bila izdelana s taljenjem tehnično čistega aluminija (AI99.5) in predzlitin AIMnIO, AIBe5,5, AICu50, AIZrlO, AISc2 in ΑΙΥ10 v električni uporovni peči. Taline zlitine je bila homogenizirana pri 750 °C in ulita v bakreno kokilo, ki je imela valjaste dele s premeri 2,5, 4, 6 in 10 mm (trdota v litem stanju je bila 100-120 HV1.
Zatem so bili nekateri vzorci plastično deformirani pri sobni temperaturi s stopnjo deformacije 50 %. Trdota deformiranih vzorcev seje povečala na 140-150 HV 1.
Vzorci so bili toplotno obdelani na zraku v električni uporovni peči. Prva temperatura staranja je bila 300 °C, prvi čas staranja pa je bil 30 ur. Po prvem staranju je bila trdota ulitih in staranih vzorcev 120-130 HV 1, medtem ko je bila trdota ulitih, deformiranih in staranih vzorcev 130-140 HV 1.
Vzorci so bili drugič toplotno obdelani na zraku v električni uporovni peči. Druga temperatura staranja je bila 400 °C, drugi čas staranja pa je bil 1 uro. Po drugem staranju je bila trdota ulitih in dvakrat staranih vzorcev 100-110 HV 1, medtem ko je bila trdota ulitih, deformiranih in dvakrat staranih vzorcev 110-120 HV 1.
Vzorci so bili hitro ohlajeni v vodi s temperature drugega staranja. Potem so bili tretjič starani na zraku v električni uporovni peči. Tretja temperatura staranja je bila 170 °C, tretji čas staranja pa 5 ur. Po tretjem staranju je bila trdota litih in trikrat staranih vzorcev 120-130 HV 1, medtem ko je bila trdota litih, deformiranih in trikrat staranih vzorcev 130-140 HV 1.
Opisani izum je nov in prenosljiv v industrijsko prakso. Izveden je bil že v polindustrijskem okolju, vsebuje pa postopke, kot so litje, preoblikovanje in toplotna obdelava, ki se normalno izvajajo pri proizvajalcih aluminijevih zlitin.
DESCRIPTION OF THE INVENTION
Production of high-strength and temperature-resistant aluminum alloys, fortified with double excreta
Field of the Invention
The invention belongs to the field of metallurgy of non-ferrous metals, more precisely in the fields of foundry and heat treatment of aluminum alloys.
Show the problem
For aluminum and aluminum alloys it is characterized by low density, high specific strength (density per unit density) and competitive corrosion resistance. Parts made of aluminum can be made economically with a variety of manufacturing processes. Kneading alloys can be achieved by hardening with standard hardening mechanisms of a tensile strength limit value between 550 MPa and 600 MPa, but with reduced expansion (about 10%). Al-Si alloys alloyed with different alloy elements (eg AISi12CuNiMg) can achieve tensile strengths up to 400 MPa, while their extensions are up to 5%.
Most high-strength aluminum alloys are fortified by excretion. The most common heat treatment is indicated by T6. Heat treatment T6 consists of solvent regeneration, which takes place at the solvus temperature of the alloy. When solvent annealing increases the homogeneity of the alloy, the alloying elements that form the secretions pass from various intermetallic phases to a solid aluminum-based solution. Then the alloy cools rapidly (gases). The cooling rate must be large enough to retain almost all dissolved alloy elements in the solid solution. During natural aging (at room temperature) or artificial aging (at elevated temperatures, typically below 200 ° C), solids formed by aluminum alloy are formed in the solid solution.
Heat treatment T5 is an alternative to T6 treatment. In this heat treatment, the alloy is directly heated from room temperature to the artificial aging temperature, without the alloy being melted and aged. The basic condition for this is, for example, in casting, they achieve a sufficiently high cooling rate, in order to ensure that a large proportion of the alloy elements remains in the solid solution. Excretions occur during direct artificial aging.
For both heat treatments, T5 and T6, the excrements only solidify the alloy at lower temperatures. When the temperature approaches 200 ° C, they become more coarse and dissolve. This leads to a drastic reduction of the strength properties.
For advanced applications, aluminum alloys must be made in various shapes and must have an appropriate combination of low density, high strength at room temperature, thermal stability and competitive prices. In scientific literature and patents, there are several solutions to solve the above problem, which have already been used in industrial practice and are relevant to this case.
In the case of high-strength and temperature-resistant excluding non-ferrous alloys, the temperature stability is terminated at temperatures above 200 ° C, since the precipitates are frozen or even dissolved. Separating ore alloys have better temperature stability, but they are more expensive because they contain Sc. The proportion of scandium is relatively large, therefore due to limited inventories, it is not possible to produce alloys in large quantities. Alloys, solidified only with quasicrystals, can only be produced by rapid hardening, so their applicability is limited.
To give a "state of the art a) The high-strength and tempera- ture properties of the separating non-ferrous alloy without Sc
High-strength aluminum alloys originate from Al-Cu alloying alloys (AA2xxx series), Al-Si-Mg (AA6xxx series), Al-Li and Al-Zn-Mg (AA7xxx series). Alloys can be manufactured using various processes (casting, powder metallurgy, transformation) and are subsequently heat treated predominantly by thermal treatments T6 and T5. The increased thermal stability is achieved by the addition of elements such as Mn, Cr, Zr, Nb, Hf or V, which can form different types of excrements which are less soluble in aluminum than conventional secretions, and they can remain in the alloy even at elevated temperatures .
Patent WO 2002063059 A1 discloses a two step process of aging parts made of an alloy containing at least aluminum and copper. Patent WO 2008003503 A2 represents the method of manufacturing AA2xxx alloys for kneading, which have relatively large dimensions. In both alloys, Al-Cu excretions are formed during heat treatment, which can not withstand temperatures higher than 200 ° C.
U.S. Pat. No. 5,959,302 A describes alloy compositions of Al-Cu and Al-Zn-Mg alloys alloyed with Mn, Cr or Zr, and heat treated so as to produce dispersions from Al-Mn, Al-Cr or Al-Zr systems , which contribute to increased fracture toughness, resistance to fatigue and transformability.
Patent US 20170051383 A1 defines the composition of the alloy and the parameters of the three-stage aging to obtain double aluminum-based exclusions to ensure the use of inventive alloys in high-temperature applications. The alloy is alloyed with Cu and Zr, and also with Nb, Hf or V.
Patent US 5226983 A defines Al-Zr-Li-X alloys which are produced by rapid solidification. After it, the alloy is artificially aged after solvent annealing. The microstructure consists of an aluminum base and AI3 excretions (Zr, Li).
Patent WO 2011122958 A1 optimizes the Al-Mg-Si-Cu alloy for high temperature stability. Defines the chemical composition of the alloy. The aim is to achieve the L-phase as the dominant type of excretion in the prestressed state with respect to the number of excretory density.
Patent US 6074498 A defines Al-Cu-Li-Sc alloys, which are subjected to dual aging. The purpose is to achieve T1 exclusions inside aluminum grains, while on the crystalline borders the area is free of T1 excretions. On the other hand, more crude excretions θ 'and h' occur within crystalline grains as well as at and on crystalline borders. b) High-strength and temperature-resistant aluminum alloys containing Sc and L12
The L12 excrements have an ordered cubic crystal structure of the general formula AX3X, where X represents one or more elements, among which Sc, Zr and Y are the most important. Exceptions I_12 are coherent with aluminum-rich base. They occur during heat treatment and are fairly stable at elevated temperatures. In Table 1, a list of patents for aluminum alloys containing Li2. Patents reveal the chemical composition of the alloys, the processes of their manufacture (eg casting, fastening, rolling, welding, extrusion) as well as their heat treatment.
Patent US 6248453 B1 discloses aluminum alloys containing Sc, Er, Lu, Yb, Trn and U as well as at least one of the elements of Mg, Ag, Zn, Li and Cu. The alloys are made with quick hardening and are composed of an aluminum base with AI3X extracts having a crystal structure Ι_ι2.
There are several patents titled "High-strength Aluminum Alloy L12" (originally "High strength L12 aluminum alloys", see Table 1). Patents reveal a number of basic alloy compositions, which include elements of scandium, erbium, tulle, iterbium and lutetium, and at least one of the elements of gadolinium, yttrium, zirconium, titanium, hafnium or niobium. One of the possible compositions is AI- (1-8) Cu- (0.2-4) Mg- (0.1-0.5) Sc- (0.05-1.0) Zr (US 7909947). In other patents, the various alloys of basic alloys [US 8002912 B2 is the basic alloy AI- (4-25) Ni- (0.1-15) Tm (Trn is a transition metal), and in US 7871477 B2 is the basic alloy of AI- (3-6) Mg- (0.5-3) Li]. In all cases, the microstructure of the alloy after heat treatment consists of an aluminum base and L12 excretions.
Patent US 5620652 A defines aluminum alloys containing Sc, and have added Zr. They can be used for sports products, land transport, marine structures, aviation and aerospace engineering. The patent does not provide details of the heat treatment. It is assumed that the alloys have an aluminum base and ΑΙ3Χ excrements with a crystal structure of Li2.
Patent US 20100143185 A1 represents a method for the manufacture of high strength aluminum alloys containing excerpts l_12. The alloy powder is made by atomizing the melt. The composition of the alloy as defined by the invention ensures that in the powder of the alloy L12 excrements are formed which are evenly distributed in an aluminum base.
Belov and colleagues [1] developed the Al-Cu-Mn-Zr-Sc alloy, which does not require solvent regrets and quenching, in order to achieve high strength. The alloy contains after the heat treatment of the L12 excrement but not the ikozaedric quasicrystalline secretions (IQC). Instead of secretions of IQC, secretions of AI20Mn3Cu2 are formed. Their weakness is that they are formed in the form of rods and not spheres. In addition, the numerical density of these excretions is significantly lower than the IQC secretions of a spherical shape.
[1] NA Belov, AN Alabin, IA Matveeva, Optimization of phase composition of Al-Cu-Mn-Zr-Sc alloys for rolled products for the treatment and guenching requirements, J. Alloy. Compr., 583 (2014) 206-213.
Table 1: A list of patents for aluminum alloys containing L12 excrements
c) Aluminum alloys hardened with quasicrystals
Quasicrystals are crystals that have a long range arrangement, but they are not periodic. This is the main difference with periodic crystals. Aluminum alloys quasicrystalline alloys have a periodic aluminum base, in which the quasicrystalline phase is dispersed. The quasicrystalline phase can be formed during fastening and casting, but it can be added to aluminum by methods that are common in the manufacture of composites. In the manufacture of composites, the quasicrystalline particles can be added to the aluminum melt; Parts are then formed by casting. The quasicrystalline powder can be admixed to aluminum powder, and parts are made by powder metallurgy.
Patent US 5593515 A discloses the manufacture of an alloy having the general formula Ali, aiQaMtoXcTd. In this case Q represents at least one of the Mn, Cr, V, Mo and W elements; M represents at least one of the elements Co, Ni, Cu and Fe; while X denotes Y or Mm (Mischmetal; an alloy containing several rare earth elements); T denotes at least one of the elements of the group Ti, Zr and Hf; indices a, b, c and d denote the content of the elements in atomic percentages: 1 ^ a ^ 7, 0> 5, 0> c ^ 5 and 0> di 2. The alloy has excellent hardness and strength for both low and high temperatures, and excellent thermal resistance and ductility. The products can be manufactured by rapid compression, heat treatment of quick-hardening parts, or by consolidation of the alloy made by rapid solidification.
Patent US 5419789 A detects aluminum alloys containing Al and at least two transition elements in atomic proportions between 0.1% and 25%, in which the quasicrystalline particles are evenly distributed in an aluminum base. The products can be manufactured by quick-hardening, heat treatment of quick-hardening parts, or by consolidating the alloy made with quick curing.
Schurack and colleagues [2, 3] wanted to improve the properties of aluminum alloys by quasicrystals. The alloys were made by melt spinning rapidly, mechanical alloying and casting. Mechanical alloying of stable AICuFe quasicrystals and aluminum powder have not been reported to provide an adequate combination of strength and ductility. Addition Al-Mn alloys increased the tendency to produce quasicrystals, probably by stabilizing the quasicrystalline structure in the melt. This allowed the formation of quasicrystals directly in the cooling of the melt. The milled and extruded fast-rock wires of the alloy AI92Mn6Ce2 reached a strength of about 800 MPa and a stretch of ~ 25%, while the conventional cast bars had a tensile strength of about 500 MPa and an expansion of ~ 20%.
Song and colleagues [4] found that the additive Be significantly decreases the critical cooling rate for the formation of quasicrystals in solidification and the minimal addition of Mn. In their alloys, quasicrystals were formed in conventional casting processes (for example, in compression casting). However, in addition to quasicrystals, their alloys contained other intermetallic phases that adversely affect the strength properties. Improved alloys were prepared by Rozman and colleagues [5].
[2] F. Schurack, J. Eckert, L. Schultz: Synthesis and mechanical properties of the part of quasicrystal-reinforced Al-alloys, Acta materialia, 49 (2001) 1351-1361 [3] F. Schurack, J. Eckert, L Schultz: Synthesis and mechanical properties of quasicrystalline Al-based composites, Quasicrystals, Structure and Physical Properties, Wiley-VCH GmbH & Co. KgaA, VVeinheim, 2003, 551-569 [4] GS Song, E. Fleury, SH Kirn, WT Kirn, DH Kirn: Enhancement of quasicrystal-forming ability in Al-based alloys by Be-addition, Journal of Alloys and Compounds , 342 (2002) 251-225 [5] N. Rozman, J. Medved, F. Zupanic, Microstructural evolution in Al-Mn-Cu- (Be) alloys, Philos. Mag., 91 (2011), pp. 4230-4246. d) Quasicrystalline precipitates in aluminum alloys
Kirn and colleagues [6] discovered decagonal quasicrystalline secretions in high-speed and annealed commercial AISI 2024 alloy aluminum containing 2 wt. % Li. Decagonal quasicrystalline secretions were formed from a solid solution at 400 ° C. Zhang and colleagues [7, 8] studied the processes of annealing solid suspensions in some high-speed aluminum alloys with transition metal elements by electron microscopy. It has been found that quasicrystalline excretions can be generated in an aluminum basis in binary Al-Cr and Al-Fe, as well as in Al-V, Al-Cr and Al-Mo systems, if they only contain smaller amounts of Fe.
Zupanič et al. [9] discovered ikozaedric excrements in Al-Mn-Be-Cu alloys molded into a copper die, which was irrigated for 24 hours at 300 ° C. Kinetics and the elimination mechanism at 300 ° C were investigated by Bončina and Zupanič [10].
There is also a patent relating to quasicrystalline secretions (US 5632826). But the secretions are in iron alloy, so the patent is not related to this invention.
[6] DH Kim, K. Chattopadhyay, B. Cantor, QUASI-CRYSTALLINE AND RELATED CRYSTALLINE PHASES IN A RAPIDLY SOLIDIFIED 2024-2LI ALUMINUM-ALLOY, Acta Metallurgica Et Materialia, 39 (1991) 859-875.
[7] XD Zhang, YJ Bi, MH Loretto, STRUCTURE AND STABILITY OF THE PRECIPITATES IN MELT SPUN TERNARY AL-TRANSITION-METAL ALLOYS, Acta Metallurgica Et Materialia, 41 (1993) 849-853.
[8] X .D. Zhang, MH Loretto, Stability and decomposition mechanisms of supersaturated solid solutions in rapidly solidified aluminum transition metals, Materials Science and Technology, 12 (1996) 19-24.
[9] ZUPANIČ, Franc, WANG, Di, GSPAN, Cristian, BONČINA, Tonica.
Precipitates in a quasicrystal-strengthened Al-Mn-Be-Cu alloy. Materials characterization, ISSN 1044-5803. [Print ed.j, Aug. 2015, vol. 106, p. 93-99. http://www.sciencedirect.com/science/article/pii/S1044580315001606, doi: 10.1016 / j.matchar.2O15.05.013.
[10] BONČINA, Tonica, ZUPANIČ, Franc. In situ TEM study of precipitation in a quasicrystal-strengthened Al-alloy. Archives of metallurgy and materials, ISSN 1733-3490, 2017, vol. 62, iss. 1, p. 5-9. http://www.imim.pl/files/archiwum/Vol1_2017/01 .pdf, doi: 10.1515 / amm-2017-0001
Description of the new solution
The invention The manufacture of high-strength and temperature-resistant aluminum alloys, fortified with double excrements, is a process for the production of high-strength and temperature-resistant aluminum alloys, which are solidified by dual quasicrystalline and Li2-secretions. The alloys produced are suitable for use in the automotive, aerospace and aerospace industries, as well as in construction and elsewhere.
The required properties can be achieved by an appropriate combination of the chemical composition of the alloy, solidification of the melt by any casting method in which the cooling rate in the melt exceeds 100 K / s just before the start of the solidification, and the two or three stage heat treatment (T5). Before heat treatment, castings may be cold or warmly plastic deformed by any transformation technology.
The heat-treated aluminum alloy, which has high strength and thermal stability, contains Mn: 2.0-5.0 wt. %;
Cr: 0.001-2.0 wt. %;
Cr + Mn: 2.0-5.0 wt. %; V: 0.001-0.5 wt. %;
Cu: 2.0-4.5 wt. %;
Be: 0.001-0.9 wt. %;
Sc: 0.05-0.5 wt. %; it contains at least one of the following elements Zr: 0.001-0.4 mass. %; Y: 0.001-0.4 wt. %;
Ti: 0.001-0.4 mass. %;
Hf: 0.001-0.4 wt. % in
Nb: 0.001-0.4 wt. %; Al and unavoidable impurities remain, the total value of which should not exceed 0.5% by weight. %.
The alloy, within the said composition, is composed of an aluminum base, which is predominantly ikozaedric quasicrystalline secretions (IQC-secretions) and L12 excretions after appropriate casting and heat treatment. The alloy elements Mn, Cr and V are necessary to form upon the clasification of the quasicrystalline phase. The elements Cr and V are required to form around the quasicrystalline nuclei of Mn rich rich in Cr and V rich in heat treatment. A small amount of beryllium ensures the formation of a quasicrystalline phase in casting when the cooling rate exceeds 100 K / s. Beryllium also accelerates the secretion of quasicrystalline secretions during heat treatment. Scandium and elements of group X (yttrium, zirconium, titanium, hafnium, and niobium) are essential in order to form the l_i2 excreta which have a crystalline structure arranged. The combination of strontium with any element of group X enables the formation of the so called AbiSr, X). In these excrements, scandium is mainly found in nuclei of excreta, while elements X are in their shells. The presence of copper in alloy allows the formation of copper-rich copper (Θ "or Θ") alloys in the aluminum base between quasicrystalline and Li2-secretions in the third, low temperature heat treatment, and in-situ transformation of the quasicrystalline phase into the T-phase (AI2oMn3Cu2) at higher temperatures use.
The alloy can be made in a liquid state by melting in an induction or any other furnace. Melting in a vacuum or protective atmosphere is recommended in order to prevent the loss of alloy elements, alignment and the formation of oxides. Technically pure aluminum and pre-alloys, which are available on the market, can be used as inputs (eg AICu50, ΑΙΥ10).
Any transition to solid state can be carried out using any casting process in which the cooling speed exceeds 100 K / s. These processes include, but are not limited to, gravity casting in permanent molds, high pressure castings, centrifugal casting, continuous casting, single and double casting. Suitable cooling rates ensure that (1) the quasicrystalline phase is formed primarily at crystalline borders, which during the subsequent heat treatment prevents the growth of crystal grains of aluminum; and (2) that an appropriate amount of alloy elements is dissolved in an aluminum base, allowing the separation of different types of residues during further heat treatment (modified heat treatment T5).
The alloy which is the subject of the present invention has the appropriate transformability, so it can be deformed plastically before any heat treatment by any transformation process prior to heat treatment. Plastic deformations increase the homogeneity of the alloy, breaks down the particles of the phases formed during clotting, and can also accelerate the processes of elimination in heat treatment. The plastic deformation process is an option.
Heat treatment consists of two or three artificial aging steps representing modified heat treatment T5.
The purpose of aging at the first aging temperature and at the first aging time is to achieve an extremely high density of icosahedric quasicrystals. The quasicrystalline represents the state of matter in which atoms are properly arranged in space, but are not periodic. The icosahedral quasicrystals are quasiperiodic in three directions - in the space. The icosahedral quasicrystals have a very high degree of symmetry, so they often grow in a spherical form, which is an advantage compared to the growth of other phases in aluminum alloys that grow in the form of needles or tiles. Quasiperiodicity allows excellent matching of icosahedral quasicrystals with an aluminum base, so the surface energy between the phases is very small. Small surface energy allows homogeneous formation of IQC secretions, which occur in very large numbers. The size of IQC excreta is 10-15 nm, and the distance between the particles is 30-40 nm. The mobility of the M-atoms determines the size and distance between the particles. Therefore, aging requires a temperature of between 260 ° C and 340 ° C and a time of 2-90 h. Quasicrystalline secretions contain mainly aluminum and manganese. During the first aging, AI3SC cubes can be formed between IQC secretions that are less than 10 nm. The microstructure after first aging consists of IQC and AI3Sc excreta.
The goal of the second aging is to make the microstructure more stable when the alloy is exposed to elevated temperatures during use. The temperature of the second aging must be higher than the temperature of the first aging. Second aging is carried out in a temperature range between 350 ° C and 490 ° C, and the duration is from 15 minutes to 10 hours. Among other things, quasi-crystalline secretions, which occurred during the first aging process, are also aging, and they are also undermined. During the fog, their number is reduced. In alloys containing Cr and V, the nucleus is formed around the core of an icosahedric crystal rich in Mn, a shell rich in Cr and V. Since the diffusivity of Cr and V is smaller than Mn, the shell makes it difficult to exclude the excreta at the exposure of the alloy to elevated temperatures . I_i2-secretions rich in Scandium (AI3Sc) grow further. At this stage, the elements X (Zr, Y, Ti, Hf, Nb) will form a shell around a scandium-rich nucleus of L12 excreta.
Elements X have lower diffusivity than scandium. Thus, the shell rich in elements X will greatly aggravate the erosion of Li2 secretions. The microstructure after the second aging will contain lupine IQC secretions, which are large 20-50 nm, and L12 peak secretions, which are large 10-20 nm and are evenly distributed in the space between the IQC secretions. Such a microstructure is very stable to temperatures close to the temperatures of the second aging (max. 450 ° C).
Third aging is an option. Its purpose is to extract rich copper from copper from solid solution, in rooms between IQC and I_i2-secretions. It is required that the alloy be quenched in water from the second aging temperature and then heated to the temperature of the third aging between 120 ° C and 190 ° C. The duration of the third aging is 2-16 hours. The copper content of IQC and Li2 excretes is very small, and Cu remains at the second aging temperature almost entirely in the solid solution. With quenching from the second aging temperature, keep it in a solid solution. When heated to the temperature of the third aging, it is eliminated in the form of copper-rich secretions: Θ 'and Θ ". This increases the strength of the alloy at low temperatures. However, the temperature stability does not change, since these secretions are re-dissolved at temperatures above 200 ° C.
An important advantage of this method is that it can be achieved by casting processes, which are established in aluminum foundries, the appropriate molds and the desired initial microstructure, which enables successful heat treatment. The alloy elements are relatively small. In this way, the molds can also be plastic deformed if necessary, because they have the appropriate ductility. Quantities of alloy elements, especially those with a high price (eg scandium), are small. Thus, the cost per unit of properties is also small. This is important in conjunction with aluminum scandium-alloyed alloys (eg EP 2598664 B1). Icocadroid and IQC secretions are coherent with an aluminum base, so they can be formed in much larger numerical densities than disperzids. The so-called alloys give far more possibilities to achieve properties than heat treatment and plastic deformation.
SUMMARY OF THE INVENTION "Manufacture of high-strength and temperature-resistant aluminum alloys fortified with double excreta"
The chemical composition of the alloy was:
The alloy was made by melting the technically pure aluminum (AI99.5) and the pre-cast AIMnIO, AIBe5.5, AICu50, AIZrlO, AISc2 and ΑΙΥ10 in the electric resistance furnace. The melt alloy was homogenized at 750 DEG C. and poured into a copper mold having cylindrical portions with diameters of 2.5, 4, 6 and 10 mm (hardness in cast state was 100-120 HV1.
Then, some samples were plastic deformed at room temperature with a degree of deformation of 50%. The hardness of deformed sample sessions increased to 140-150 HV 1.
The samples were heat-treated in the air in an electrical resistance furnace. The first temperature of aging was 300 ° C, and the first aging time was 30 hours. After the first aging the hardness of the molded and aged samples was 120-130 HV 1, while the hardness of the molded, deformed and aged samples was 130-140 HV 1.
The samples were heat-treated in the air in an electric resistance furnace for the second time. The second aging temperature was 400 ° C, while the second aging time was 1 hour. After the second aging, the hardness of casts and twice aged samples was 100-110 HV 1, while the hardness of molded, deformed and twice aged samples was 110-120 HV 1.
The samples were rapidly cooled in water from the second aging temperature. Then, for the third time, they were aged in the air in an electric resistance furnace. The third aging temperature was 170 ° C, and the third time of aging was 5 hours. After the third aging the hardness of the casts and the three times aged samples was 120-130 HV 1, while the hardness of the cast, deformed and three-fold samples was 130-140 HV 1.
The invention described is novel and transferable to industrial practice. It has already been implemented in a semi-industrial environment, but it includes processes such as casting, transformation and heat treatment, which are normally carried out with aluminum alloy producers.
Claims (4)
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SI201700256A SI25352A (en) | 2017-09-13 | 2017-09-13 | Production of high-strength and temperature resistant aluminum alloys fortified with double excretion |
| EP17468002.5A EP3456853B1 (en) | 2017-09-13 | 2017-12-27 | Manufacturing of high strength and heat resistant aluminium alloys strengthened by dual precipitates |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SI201700256A SI25352A (en) | 2017-09-13 | 2017-09-13 | Production of high-strength and temperature resistant aluminum alloys fortified with double excretion |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| SI25352A true SI25352A (en) | 2018-07-31 |
Family
ID=61024552
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| SI201700256A SI25352A (en) | 2017-09-13 | 2017-09-13 | Production of high-strength and temperature resistant aluminum alloys fortified with double excretion |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP3456853B1 (en) |
| SI (1) | SI25352A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2018379386B2 (en) | 2017-12-04 | 2021-09-23 | Monash University | High strength aluminium alloy for rapid solidification manufacturing processes |
| CN111206194B (en) * | 2020-02-24 | 2022-01-28 | 湖南人文科技学院 | Thermal mechanical treatment process for preparing aluminum alloy with high comprehensive performance |
| CN111575526B (en) * | 2020-05-22 | 2021-09-17 | 信承瑞技术有限公司 | Copper-selenium contact wire for electrified railway and preparation process thereof |
| CN114107764B (en) * | 2020-08-26 | 2022-10-21 | 宝山钢铁股份有限公司 | Jet casting and rolling 7XXX aluminum alloy thin strip and preparation method thereof |
| CN112410624B (en) * | 2020-11-05 | 2021-06-15 | 山东迈奥晶新材料有限公司 | Al-Si alloy, preparation method thereof and heat sink of 5G communication base station |
| RU2753537C1 (en) * | 2021-02-04 | 2021-08-17 | Общество с ограниченной ответственностью "Научно-производственный центр магнитной гидродинамики" | Alloy based on aluminum for production of wire and method for obtaining it |
| CN113789453B (en) * | 2021-08-17 | 2023-08-01 | 东南大学 | Method for improving high-temperature strength of heat-resistant aluminum alloy through Mn microalloying |
| CN114737142B (en) * | 2022-06-13 | 2022-08-30 | 中国航发北京航空材料研究院 | Low-stress corrosion-resistant preparation method for aluminum alloy casting through vibratory aging and cryogenic treatment |
| CN117443982B (en) * | 2023-11-16 | 2024-04-19 | 广州航海学院 | Heat-resistant aluminum alloy wire material and preparation method thereof |
Family Cites Families (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5226983A (en) | 1985-07-08 | 1993-07-13 | Allied-Signal Inc. | High strength, ductile, low density aluminum alloys and process for making same |
| JP3142659B2 (en) | 1992-09-11 | 2001-03-07 | ワイケイケイ株式会社 | High strength, heat resistant aluminum base alloy |
| SE508684C2 (en) | 1993-10-07 | 1998-10-26 | Sandvik Ab | Precision-hardened iron alloy with quasi-crystalline structure particles |
| JPH07238336A (en) * | 1994-02-25 | 1995-09-12 | Takeshi Masumoto | High strength aluminum-base alloy |
| JP2795611B2 (en) | 1994-03-29 | 1998-09-10 | 健 増本 | High strength aluminum base alloy |
| US5597529A (en) | 1994-05-25 | 1997-01-28 | Ashurst Technology Corporation (Ireland Limited) | Aluminum-scandium alloys |
| JP3053352B2 (en) | 1995-04-14 | 2000-06-19 | 株式会社神戸製鋼所 | Heat-treated Al alloy with excellent fracture toughness, fatigue properties and formability |
| US6074498A (en) | 1996-10-28 | 2000-06-13 | Mcdonnell Douglas Corporation | Heat treated Al-Cu-Li-Sc alloys |
| US6248453B1 (en) | 1999-12-22 | 2001-06-19 | United Technologies Corporation | High strength aluminum alloy |
| WO2002063059A1 (en) | 2000-10-20 | 2002-08-15 | Pechiney Rolled Products, Llc | High strenght aluminum alloy |
| RU2287600C1 (en) * | 2005-08-09 | 2006-11-20 | Государственное образовательное учреждение высшего профессионального образования "Московский государственный институт стали и сплавов" (технологический университет) | Aluminum-base material |
| WO2008003503A2 (en) | 2006-07-07 | 2008-01-10 | Aleris Aluminum Koblenz Gmbh | Method of manufacturing aa2000 - series aluminium alloy products |
| US7811395B2 (en) | 2008-04-18 | 2010-10-12 | United Technologies Corporation | High strength L12 aluminum alloys |
| US8002912B2 (en) | 2008-04-18 | 2011-08-23 | United Technologies Corporation | High strength L12 aluminum alloys |
| US7871477B2 (en) | 2008-04-18 | 2011-01-18 | United Technologies Corporation | High strength L12 aluminum alloys |
| US8778098B2 (en) | 2008-12-09 | 2014-07-15 | United Technologies Corporation | Method for producing high strength aluminum alloy powder containing L12 intermetallic dispersoids |
| WO2011122958A1 (en) | 2010-03-30 | 2011-10-06 | Norsk Hydro Asa | High temperature stable aluminium alloy |
| DE102010032768A1 (en) | 2010-07-29 | 2012-02-02 | Eads Deutschland Gmbh | High-temperature scandium alloyed aluminum material with improved extrudability |
| US10273564B2 (en) | 2014-02-14 | 2019-04-30 | Indian Institute Of Science | Aluminium based alloys for high temperature applications and method of producing such alloys |
-
2017
- 2017-09-13 SI SI201700256A patent/SI25352A/en active IP Right Grant
- 2017-12-27 EP EP17468002.5A patent/EP3456853B1/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| EP3456853B1 (en) | 2020-02-19 |
| EP3456853A1 (en) | 2019-03-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| SI25352A (en) | Production of high-strength and temperature resistant aluminum alloys fortified with double excretion | |
| JP5463795B2 (en) | Aluminum alloy and heat-resistant aluminum alloy material and method for producing the same | |
| Penghuai et al. | Tensile properties of high strength cast Mg alloys at room temperature: A review | |
| KR101258470B1 (en) | High-Strength High-Ductility Ignition-Proof Magnesium Alloy | |
| EP1640466A1 (en) | Magnesium alloy and production process thereof | |
| JP2005530046A (en) | Creep-resistant magnesium alloy | |
| WO2013115490A1 (en) | Magnesium alloy having high ductility and high toughness, and preparation method thereof | |
| CN109930045B (en) | High-strength-toughness heat-resistant Mg-Gd alloy suitable for gravity casting and preparation method thereof | |
| US20070204936A1 (en) | Magnesium Alloy | |
| Yang et al. | Effects of Sn addition on as-cast microstructure, mechanical properties and casting fluidity of ZA84 magnesium alloy | |
| CN110016593B (en) | Aluminum alloy and preparation method thereof | |
| Bonnah et al. | Microstructure and mechanical properties of AZ91 magnesium alloy with minor additions of Sm, Si and Ca elements | |
| WO2011035653A1 (en) | High-strength heat-proof aluminum alloy material containing cobalt and rare earth and producing method thereof | |
| Zhou et al. | Effect of cerium on microstructures and mechanical properties of AZ61 wrought magnesium alloy | |
| Peng et al. | Effect of solution treatment on microstructure and mechanical properties of cast Al–3Li–1.5 Cu–0.2 Zr alloy | |
| CN109852859B (en) | High-strength-toughness heat-resistant Mg-Y-Er alloy suitable for gravity casting and preparation method thereof | |
| KR20160136832A (en) | High strength wrought magnesium alloys and method for manufacturing the same | |
| Ravi et al. | The effect of mischmetal addition on the structure and mechanical properties of a cast Al-7Si-0.3 Mg alloy containing excess iron (up to 0.6 Pct) | |
| YANG et al. | Effects of holding temperature and time on semi-solid isothermal heat-treated microstructure of ZA84 magnesium alloy | |
| Pezda | Effect of the T6 heat treatment on change of mechanical properties of the AlSi12CuNiMg alloy modified with strontium | |
| JP2006028548A (en) | Magnesium alloy to be plastic-worked and magnesium alloy member | |
| Elagin | Ways of developing high-strength and high-temperature structural aluminum alloys in the 21st century | |
| KR101680041B1 (en) | Wrought magnesium alloy having high ductility and high toughness and method for preparing the same | |
| CN109943759B (en) | High-strength-toughness heat-resistant Mg-Er alloy suitable for gravity casting and preparation method thereof | |
| JP2006161103A (en) | Aluminum alloy member and manufacturing method therefor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| OO00 | Grant of patent |
Effective date: 20180821 |