Isomorphous β-Stabilizers: Lub Ductility thiab Deep Hardening Enablers
Isomorphous β-stabilizers qhia titanium's BCC siv lead ua qauv thiab ua kom tiav cov khoom solubility hauv β-theem. Cov ntsiab lus no-Mo, V, Nb, Ta, W- tsim cov pob txha ntawm α+β thiab β-titanium alloys.
3.1 Vanadium: Tus khub Ti-6Al-4V
V is the classic β-stabilizer in Ti-6Al-4V, the most widely used titanium alloy accounting for >50% ntawm kev siv titanium thoob ntiaj teb. V ntxiv ntawm 4 wt% depress lub β-transus txaus kom pab tau ob-phase microstructures nrog kwv yees li 10-50% β-theem ntawm chav tsev kub.
V muab ntau lub luag haujlwm tseem ceeb:
β tuav: Pab kom microstructural tswj los ntawm kev kho cua sov
Lub zog tsis muaj embrittlement: Tsis zoo li interstitial ntxiv dag zog, V tuav ductility thaum pab txhawb rau cov khoom muaj zog ntxiv.
Fabricability: Ob -theem microstructure muaj qhov zoo sib npaug ntawm kev ua haujlwm kub thiab cov khoom siv tshuab kawg
3.2 Molybdenum: Lub Zog Muaj Zog β-Stabilizer
Mo yog kwv yees li ob zaug zoo li V hauv stabilizing β-theem, ntsuas los ntawm molybdenum equivalency tswvyim ([Mo]eq). Txhua 1 wt% Mo muab β-stabilizing zog sib npaug li kwv yees li 2 wt% V .
Theem tswj: Nyob rau hauv alloys xws li Ti-15Mo-3Al-2.7Nb-0.2Si (siv rau high-strength aerospace fasteners), Mo enables ua tiav β- tuav ntawm quenching, ua raws li los ntawm kev tswj α nag lossis daus thaum laus .
Corrosion kuj: Mo ntxiv txhim khu kev ua haujlwm hauv kev txo cov kua qaub ib puag ncig. Ti-Mo alloys tsim cov yeeb yaj kiab passive uas muaj MoO₃ sib xyaw nrog TiO₂, muab kev ruaj ntseg zoo dua hauv HCl cov kev daws teeb meem piv rau cov titanium tsis muaj khoom.
Kev nce qib tsis ntev los no: Zhang et al. pom tau hais tias Mo- muaj cov alloys nrog tswj N ntxiv ua tiav cov khoom tshwj xeeb los ntawm cov qauv lamella heterogeneous. Lawv Ti-2.8Cr-4.5Zr-5.2Al-0.4N alloy ua tiav 1532 MPa yield zog nrog 10.2% uniform elongation-txoj hauj lwm nws ntawm qhov zoo tshaj plaws ua ke qhia rau titanium alloys .
3.3 Niobium thiab Tantalum: Biocompatible Stabilizers
Nb thiab Ta tau txais txiaj ntsig zoo hauv kev siv biomedical qhov twg ntev -lub sij hawm biocompatibility yog qhov tseem ceeb. Tsis zoo li V, uas ua rau muaj kev txhawj xeeb txog cytotoxicity, Nb thiab Ta yog lub cev tsis muaj zog.
Tsawg modulus tsim: Nb ntxiv pab kom β-titanium alloys nrog elastic moduli hauv qab 50 GPa-ze rau pob txha 10-30 GPa thiab deb ntawm 110 GPa ntawm Ti-6Al-4V. Ti-35Nb-7Zr-5Ta alloys ua piv txwv txoj hauv kev no, sib txuas Nb nrog Zr thiab Ta kom txo tau kev ntxhov siab tiv thaiv hauv orthopedic implants.
Passive zaj duab xis txhim kho: Nb thiab Ta oxides koom ua ke rau hauv cov yeeb yaj kiab passive nto, ua kom nws ruaj khov thiab tiv thaiv corrosion. Hauv cov tshuaj chloride-muaj ib puag ncig, Nb- hloov cov yeeb yaj kiab passive qhia txo qis qhov tsis xws luag ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom Nb
3.4 Tungsten: Siab -Tub kub Oxidation Resistance
Cov kev tshawb fawb tsis ntev los no los ntawm Gautier et al. tshuaj xyuas W, Ta, thiab Hf ntxiv rau kev siv siab - kub. Tom qab 5000 h raug ntawm 650 ° C hauv huab cua, W tau pom qhov txo qis tshaj plaws hauv oxidation kinetics .
Mechanism: W txhawb kev tsim Ti₂N ntawm oxide / hlau sib txuas, tsim kom muaj nitrogen- nplua nuj txheej uas txo cov pa oxygen rau hauv cov hlau loj. Lub ternary Ti-10Al-2W (at%) alloy outperformed lub lag luam high-temperature alloy Ti6242S nyob rau hauv oxidation kuj.
Kev lag luam-tawm: W yog ntom (19.3 g / cm³), thiab hnyav ntxiv negate titanium qhov ceev kom zoo dua. Qhov kev sib tw yog nyob rau hauv kev txheeb xyuas qhov tsawg kawg nkaus concentration (feem ntau<2 wt%) that provide oxidation benefits without unacceptable weight penalties.
Eutectoid β-Stabilizers: Tus nqi-Txoj kev muaj zog
Eutectoid- tsim cov ntsiab lus-Fe, Cr, Ni, Cu, Si- kuj ua rau β-transus tab sis txawv ntawm isomorphous stabilizers nyob rau hauv lawv lub peev xwm los tsim intermetallic compounds los ntawm eutectoid decomposition.
4.1 Hlau: Tsawg-Cov nqi ruaj khov
Fe yog lub zog thiab pheej yig β-stabilizer. Nws tus nqi nrawm nrawm ua rau cov lus teb ceev ceev rau kev kho cua sov, tab sis kuj txhawb kev sib cais thaum lub sij hawm solidification. Fe-muaj cov alloys yuav tsum tau ua tib zoo ua kom tsis txhob β-flecking- thaj chaw hauv cheeb tsam ntawm enriched β-stabilizer uas tsim cov khoom tsis yog-cov khoom siv kho tshuab.
4.2 Silicon: Siab -Tub kub Creep Resistance
Si ntxiv ntawm 0.1–0.5 wt% yog tus qauv nyob ze -α siab- kub alloys (piv txwv li, Ti-6242S, IMI 834). Si muab ob qhov txiaj ntsig:
Solid solution reinforcing: Si hauv cov tshuaj impedes dislocation nce ntawm qhov kub siab
Silicide nag lossis daus: Fine (Ti, Zr)₅Si₃ precipitates tus pin grain ciam teb thiab sub- ciam teb, retarding creep deformation
Kev ua haujlwm tsis ntev los no los ntawm Gautier et al. paub tseeb tias Si, ua ke nrog cov khoom refractory, muab kev sib koom ua ke txhim kho nyob rau hauv ob qho tib si creep thiab oxidation tsis kam ntawm 600-650 ° C.
Neutral Elements: Microstructure Refiners
Zr, Hf, thiab Sn ua rau muaj kev cuam tshuam tsawg heev ntawm β-transus kub tab sis muab cov tshuaj muaj zog ntau ntxiv hauv ob theem α thiab β.
5.1 Zirconium: Ua tiav Solubility Partner
Zr yog miscible kiag li nrog Ti nyob rau hauv ob qho tib si α thiab β theem -ib yam ntxwv tshwj xeeb tshwm sim los ntawm lawv txoj hauj lwm nyob rau hauv pab pawg IVB ntawm lub sij hawm. Qhov no tiav solubility enables:
Ua kom muaj zog yam tsis muaj theem tsis ruaj khov: Zr ntxiv dag zog los ntawm cov txheej txheem kev daws teeb meem tsis muaj kev hloov pauv theem, ua kom yooj yim alloy tsim.
Kev txhim kho corrosion: Nyob rau hauv ib puag ncig marine, Zr- muaj cov alloys tsim cov yeeb yaj kiab zoo dua qub. ZrO₂ koom ua ke rau hauv TiO₂ txheej, txo cov concentration ntawm cov pa oxygen thiab pab txhawb kev tiv thaiv chloride nres.
Kev tshawb pom tsis ntev los no: Kev tshawb fawb ntawm Ti575 alloys (Ti-5Al-7.5V-0.5Si) piv Mo thiab Zr ntxiv tau pom tias thaum Zr muab α refinement tsawg dua Mo, nws txhawb silicide nag lossis daus los ntawm kev txo cov nucleation teeb meem.
5.2 Ib
Sn muab cov kev daws teeb meem kom muaj zog ntxiv yam tsis muaj kev hloov pauv theem stability. Nyob rau hauv siab -kub alloys (Ti-6242, Ti-1100), Sn pab txhawb kom nkag siab los ntawm cov tshuaj daws teeb meem thiab los ntawm kev hloov kho silicide nag lossis daus.
Txuas ntxiv...
