7075 Aluminium Alloy: Lub zog ntawm qhov kev txwv ntawm Wrought Aluminium
7075 aluminium alloy nyob qhov tshwj xeeb-thiab feem ntau nkag siab tsis zoo- txoj hauj lwm nyob rau hauv wrought aluminium alloy tsev neeg. Nws sawv cev rautswv yim sab sauv ciam teb ntawm achievable zog nyob rau hauv cov pa aluminium alloys. Nrog rau cov cuab yeej cuab tam piv rau ntau yam tsawg - carbon steels tsis tau ntawm qhov hnyav dua, 7075 yog dav suav tias yog qhov ntsuassiab -lub zog aluminium alloy. Nws lub zog zoo tshaj -rau- qhov hnyav piv ua rau nws tseem ceeb hauv aerospace thiab lwm yam kev ua haujlwm siab - kev ua haujlwm engineering, thiab nws yog cov khoom tseem ceeb muab los ntawmGNEE.
Engineers nquag xa mus rau7075-T6raws li "steel-zoo li aluminium." Nws cov txiaj ntsig thiab lub zog tensile nyob deb tshaj cov khoom siv feem ntau siv xws li 6061. Qhov kev ua tau zoo no piav qhia nws txoj kev siv hauvaircraft fuselage thav duab, tis spars, thiab precision nce toj thiab cov cuab yeej kev nyab xeeb, qhov twg qhov hnyav txo yog qhov tseem ceeb thiab kev thauj khoom muaj kev ntxhov siab heev.
Txawm li cas los xij, tus nqi ntawm 7075 dag tsis yog hauv nws lub zog xwb tab sis kuj nyob rau hauvengineering compromises yuav tsum tau ua kom tiav nws. Lub siab zinc thiab tooj liab cov ntsiab lus uas ua rau muaj zog tshwj xeeb kuj txo qis kev tiv thaiv corrosion, tshem tawm cov weldability, thiab ua rau kom cov machining complexity. Xaiv 7075 yog li yuav tsum tau txiav txim siab thiab paub txog engineering.
7075 Aluminium Alloy yog dab tsi?
Alloy System thiab Composition
7075 txhuas yog qhov zoo tshaj plaws alloy ntawm lub7 xxxxxxxxx, ib pab pawg tshwj xeeb tsim los ua kom muaj zog ntau dua li kev tsim khoom.
Engineering Lub luag haujlwm ntawm 7xxx Series Aluminium Alloys
Lub 7xxx series yog txhais los ntawm tusAluminium–Zinc–Magnesium–Copper (Al{0}}Zn-Mg-Cu)alloy system. Nws txoj hauj lwm ntawm aluminium alloys tuaj yeem nkag siab los ntawm kev sib piv:
5xxx Series (piv txwv li, 5083)
Tsis yog-kub- kho tau cov alloys hais txog corrosion kuj thiab weldability; dav siv nyob rau hauv marine hulls.
6xxx Series (piv txwv li, 6061)
Thaum tshav kub kub- kho tau, sib npaug alloys ua ntej muaj ntau yam, extrudability, thiab corrosion kuj; feem ntau nyob rau hauv kev siv cov txheej txheem.
7xxx Series (piv txwv li, 7075)
Thaum tshav kub kub- kho tau cov alloys optimized rau siab tshaj plaws lub zog thiab nruj, txia weldability thiab corrosion kuj mus cuag superior mechanical kev ua tau zoo.
Vim li cas Zinc yog qhov tseem ceeb ntawm kev ua kom muaj zog
Zinc (Zn) yog qhov tseem ceeb alloying caij hauv 7075, feem ntau suav rau5.1–6.1 wt.%. Ua ke nrog magnesium (Mg) thiab tooj liab (Cu), zinc pab tsim kom muaj zog heevMgZn₂ (η′) dej nagthaum kho cua sov.
Tsis zoo li Mg₂Si precipitates pom nyob rau hauv 6061, η′ precipitates nyob rau hauv 7075 tsim ib tug ntau denser thiab zoo barrier rau dislocation motion nyob rau hauv lub siv lead ua lattice, uas ua rau muaj zog ntau dua.
Engineering Insight:
7075 tsis yog tsuas yog siab dua - qib version ntawm 6061. Nws yog ib qho tshwj xeeb alloy xaiv thaumlub zog siab tshaj plaws yog tus tsim qauv tsav tsheb, thiab nws cov lag luam tawm -offs- txwv tsis pub corrosion, weldability tsis zoo, thiab machining nyuaj- tau txais tag nrho.
Chemical Composition thiab Strength Mechanism ntawm 7075 Aluminium
Lub zog tshwj xeeb ntawm 7075 txhuas tau ncaj qha los ntawm nws cov tshuaj ua tib zoo tswj cov tshuaj muaj pes tsawg leeg.
Cov tshuaj muaj pes tsawg leeg (wt.%)
| Element | Min. | Max. | Primary Engineering Function |
|---|---|---|---|
| Zinc (Zn) | 5.1 | 6.1 | Lub hauv paus tseem ceeb ntxiv dag zog; enables MgZn₂ nag lossis daus |
| Magnesium (Mg) | 2.1 | 2.9 | Qhov tseem ceeb rau nag lossis daus hardening thiab lub zog |
| Copper (Cu) | 1.2 | 2.0 | Ua kom muaj zog thiab hardness; txo corrosion kuj |
| Chromium (Cr) | 0.18 | 0.28 | Kev tswj cov qauv nplej txhim kho SCC tsis kam |
| Hlau (Fe) | – | 0.5 | Impurity, tswj kom ruaj khov |
| Silicon (Si) | – | 0.4 | Impurity, khaws cia qis |
| Aluminium (Al) | Tshuav | Tshuav | Base hlau matrix |
Kev Tshawb Fawb ntawm T6 Kev Kho Hniav Kub: Cov nag lossis daus Hardening
7075 txhuas ua tiav nws cov khoom siv kho tshuab siab tshaj plaws los ntawmnag lossis daus hardening, ua tib zoo tswj cov txheej txheem thermal:
Kev kho cua sov
Cov hlau yog rhuab kom txog thaum zinc, magnesium, thiab tooj liab yaj mus rau hauv ib qho kev daws teeb meem - theem.
Quenching
Cov cua txias nrawm nrawm cov khoom no nyob rau hauv lub xeev supersaturated.
Artificial laus (T6)
Tswj reheating tso cai rau nplua η′ precipitates tsim thoob plaws hauv matrix.
Qhov no ntom precipitate qauv piav qhia ob qho tib silub zog txawv txawvntawm 7075-T6 thiab nwstxo ductility, raws li tib yam ntxwv uas tiv thaiv deformation kuj txwv elongation ua ntej tawg.
Lub cev thiab cov cuab yeej cuab tam ntawm 7075 Aluminium
Cov kws kho tsheb yuav tsum ntsuas 7075 raws li nws qhov kev kub ntxhov, raws li kev coj tus cwj pwm sib txawv ntawm cov tempers.
Tej yam cuab yeej cuab tam los ntawm Temper
| Khoom | 7075-O (Annealed) | 7075-T6 / T651 | 7075-T73 | Engineering Implication |
|---|---|---|---|---|
| Tensile zog | ~ 228 MPa | ~ 572 MPa (83 ksi) | ~ 505 MPa | T6 nyob rau ntawm qhov muaj zog aluminium alloys |
| Yield zog | ~ 103 MPa | ~ 503 MPa (73 ksi) | ~ 435 MPa | T6 yield zog ≈ 2 × ntawm 6061-T6 |
| Elongation | ~17% | ~11% | ~13% | T6 muaj tsawg formability |
| Brinell Hardness | ~ 60 HB | ~ 150 HB | ~ 135 HB | High hnav thiab dent kuj |
| Fracture Toughness | Siab | Tsawg | Nruab nrab | T73 muab kev txhim kho toughness |
Lub cev tseem ceeb rau siab -Load Design
Ceev:2.81 g / cm³
Elastic Modulus:71.7 gvp
Thermal conductivity:~ 130 W / m·K (qis dua 6061)
Cov Lus Cim Tsim:
Txawm hais tias 7075 yog kwv yees80% muaj zog tshaj 6061, nws cov tawv nqaij yog ze li qub. Yog tias tus qauv tsim yog deflection- txwv tsis pub dhau lub zog- txwv, hloov mus rau 7075 ib leeg yuav tsis txo khoov yam tsis hloov pauv geometry.
7075-T6: Lub zog tiv thaiv kev ntxhov siab-Corrosion Risk
T6 temper muabqhov siab tshaj plaws ua tiav lub zog tab siskuj qhia ntxiv susceptibility raukev nyuaj siab-corrosion cracking (SCC).
Strength vs. SCC Trade-Tawm
Mechanism:
Nyob rau hauv ib puag ncig corrosive ua ke nrog kev ntxhov siab tensile, cov kab nrib pleb tuaj yeem pib ua raws li thaj tsam ntawm cov qoob loo thiab nthuav tawm sai, uas tuaj yeem ua rau tsis ua tiav sai.
Kev daws teeb meem - T73 Temper:
Rau cov qauv aerospace tseem ceeb uas raug rau sab nraum zoov, cov kws ua haujlwm feem ntau xaiv7075-T73. Qhov no overaged mob txis kwv yees li10-15% zogtab sis ua tau zoo txhim kho tsis kam rau SCC thiab exfoliation corrosion.
Qhov tseem ceeb ntawm T651 Kev Nyuaj Siab
Rapid quenching induces siab residual stresses nyob rau hauv tuab phaj khoom. Thaum lub sij hawm machining, cov kev ntxhov siab no tuaj yeem tso tawm thiab ua rau muaj kev cuam tshuam.
Qhov Zoo Tshaj Plaws:
Ib txwm qhia7075-T651rau CNC machining. Lub npe "51" qhia tau hais tias txhua yam stretching los txo cov kev ntxhov siab sab hauv thiab ua kom muaj kev ruaj ntseg ntawm qhov ntev - ib qho kev xaiv niaj hnub muab los ntawmGNEE.
Machinability ntawm 7075 Txhuas hauv CNC Daim Ntawv Thov
7075 txhuas feem ntau piav raws li "machinable heev," tab sis cov lus piav qhia no yuav tsum muaj nuance.
Vim li cas 7075 Tshuab Zoo-Thiab, Xav Tau Kev Pabcuam
Nws hardness thiab tus txheeb ze brittleness (rau txhuas) cia nws tsimluv, zoo - tawg chips, tsis zoo li softer alloys xws li 3003 lossis 5052. Qhov no ua rauzoo heev nto finish zoo.
Txawm li cas los xij, tib yam khoom tsimsiab txiav quab yuam, muab qhov xav tau ntau dua ntawm spindles, tooling, thiab fixturing.
Pom zoo Machining Strategy
Tooling:
Cov cuab yeej ntse, polished carbide yog qhov tseem ceeb. Coatings xws liTiB₂ or DLCtxo cov tsim- nce ntug tsim.
Thermal Management:
Cov thermal conductivity qis dua 6061 txhais tau hais tias cua sov concentrates ntawm qhov txiav ntug. High -pressure coolant yog ib qho tseem ceeb los tswj qhov raug qhov tseeb.
Tool Hnav:
Cov cuab yeej siv lub neej luv dua nrog 6061 vim qhov cuam tshuam ntawm zinc thiab tooj liab.
Kev sib piv Machinability
| Feature | 7075-T6 | 6061-T6 |
|---|---|---|
| Nto tiav | Zoo heev | Zoo heev |
| Chip Tswj | Zoo heev | Zoo |
| Txiav quab yuam | Siab | Nruab nrab |
| Tool Lub Neej | Zoo | Zoo heev |
