Metallurgy hauv Kev Txhim Kho Cov Khoom Siv Nanostructured
Kev txhim kho ntawm kev tshawb fawb txog cov ntaub ntawv hauv xyoo tas los no tau qhia txog kev taw qhia meej meej: tib neeg xav tau cov khoom siv muaj zog dua, sib dua, tiv taus xeb dua, thiab ua haujlwm tau zoo dua rau ntau yam kev siv - los ntawm kev thauj mus los thiab lub zog mus rau cov khoom siv hluav taws xob thiab kev kho mob. Nyob rau hauv cov kev xav tau no, cov ntaub ntawv nanostructured tau tshwm sim ua ib qho ntawm cov kev tshawb pom zoo tshaj plaws. Cov ntaub ntawv no muaj cov yam ntxwv lossis qhov loj me ntawm qhov ntsuas nanometer (kwv yees li 1–100 nm), uas ua rau muaj ntau yam - feem ntau zoo dua - cov khoom siv kho tshuab, hluav taws xob, thermal, thiab tshuaj lom neeg piv rau cov ntaub ntawv ib txwm muaj. Qhov no yog qhov uas metallurgy ua lub luag haujlwm tseem ceeb: tsis yog tsuas yog kev tshawb fawb ntawm cov hlau, tab sis ua ib qho kev qhuab qhia uas tswj hwm yuav ua li cas cov qauv sab hauv ntawm cov ntaub ntawv raug tsim, hloov kho, thiab tswj hwm kom ua tiav cov kev ua tau zoo tshwj xeeb.
Nkag siab txog cov ntaub ntawv nanostructured thiab lawv qhov ntsuas tshwj xeeb
Cov ntaub ntawv nanostructured tuaj yeem yog cov hlau, alloys, ceramics, lossis composites uas muaj cov noob siv lead ua zoo heev lossis muaj nanoprecipitates, nanolayers, thiab txawm tias nanoscale pores. Ntawm qhov loj me no, ntau yam "tshiab" tshwm sim. Piv txwv li, thaum qhov loj me ntawm cov hlau raug txo kom txog rau qhov nanometer scale, lub zog nce ntxiv vim muaj ntau ntxiv ntawm cov ciam teb ntawm cov noob uas tiv thaiv kev txav mus los ntawm kev tawg - lub hauv paus tseem ceeb ntawm kev hloov pauv yas hauv cov hlau. Qhov xwm txheej no feem ntau piav qhia los ntawm kev sib raug zoo Hall-Petch, qhov twg lub zog nce ntxiv nrog qhov loj me ntawm cov noob txo qis (txawm hais tias ntawm qhov loj me me heev muaj qee qhov kev zam).
Ntxiv rau qhov muaj zog, cov qauv nano kuj tseem tuaj yeem ua rau kom tsis txhob hnav, txhim kho kev teb rau kev qaug zog, hloov pauv hluav taws xob / thermal conductivity, thiab cuam tshuam rau qhov ua haujlwm ntawm qhov chaw. Yog li ntawd, qhov tseem ceeb rau cov ntaub ntawv nanostructured tsis yog "me me xwb," tab sis kev tswj hwm: qhov loj me, kev faib tawm, cov duab, thiab kev ruaj khov ntawm cov qauv nanoscale yuav tsum tau ua kom haum rau lub hom phiaj.
Metallurgy ua tus "kws kes duab vajtse" ntawm cov qauv: los ntawm cov txheej txheem mus rau cov khoom
Niaj hnub nimno metallurgy tuaj yeem pom tau tias yog tus choj ntawm cov txheej txheem-qauv-khoom-kev ua tau zoo. Hauv cov ntsiab lus ntawm nanostructures, metallurgy yog lub luag haujlwm rau kev txiav txim siab cov txheej txheem tsim khoom thiab kev kho mob uas muaj peev xwm tsim cov yam ntxwv nanoscale tas li. Qhov no suav nrog lub cev metallurgy (tham txog cov qauv siv lead ua, theem, kev hloov pauv), tshuab metallurgy (deformation, hardening, tsis ua haujlwm), thiab txheej txheem metallurgy (smelting, casting, sintering, txheej, thiab cov txheej txheem tsim khoom siab heev).
Hauv kev tsim cov ntaub ntawv nanostructured, cov teeb meem metallurgical nyuaj dua los ntawm qhov rhiab heev ntawm cov ntaub ntawv me me rau qhov kub thiab txias, qhov nrawm txias, atomic diffusion, thiab lub zog ntawm qhov chaw. Nanostructures feem ntau tsis ruaj khov thermodynamically; nanograins yooj yim loj hlob thaum raug cua sov, xav tau cov tswv yim los "xauv" cov nanostructures kom tiv thaiv kev loj hlob sai ntawm cov noob.
Cov txheej txheem metallurgy rau kev tsim cov nanostructures
1. Kev Hloov Pauv Yas Hnyav (SPD)
Ib txoj hauv kev tseem ceeb hauv kev ua hlau yog los kho qhov loj ntawm cov noob los ntawm kev hloov pauv loj heev yam tsis hloov pauv qhov loj kawg. Cov txheej txheem SPD nrov suav nrog Equal Channel Angular Pressing (ECAP) thiab High-Pressure Torsion (HPT). Cov txheej txheem no yuam kom cov hlau hla dhau cov kab loj, tsim cov noob me me zuj zus, thaum kawg ncav cuag qhov loj me ultrafine lossis nanoscale.
Qhov zoo ntawm SPD yog tias nws tuaj yeem ua rau lub zog nce ntxiv yam tsis tas yuav siv cov hlau sib xyaw ua ke. Txawm li cas los xij, cov teeb meem suav nrog kev tswj hwm qhov sib xws ntawm cov qauv, kev txwv qhov loj ntawm cov khoom, thiab kev ruaj khov ntawm nanostructure thaum cov khoom siv ntawm qhov kub siab.
2. Cov hlau nplaum Nanostructured los ntawm kev nag lossis daus thiab kev sib cais hardening
Cov hlau alloy siv cov precipitates—cov khoom me me theem ob uas tsim los ntawm kev kho cua sov tshwj xeeb—kom ua kom muaj zog ntxiv. Ntawm qhov nanoscale, cov precipitates me me thiab sib npaug zos tuaj yeem tiv thaiv kev txav mus los. Piv txwv li suav nrog 2xxx/7xxx series txhuas alloys lossis nickel-based superalloys, qhov twg kub thiab lub sijhawm laus tuaj yeem tsim cov nanoprecipitates muaj zog heev.
Lwm txoj hauv kev yog oxide dispersion strengthened (ODS), uas siv cov nanometer oxide particles ruaj khov heev los txhim kho lub zog thiab kev tiv thaiv creep ntawm qhov kub siab. Cov ntaub ntawv ODS tau raug txiav txim siab dav rau lub zog thiab kev siv ib puag ncig hnyav vim tias nanodispersoids qeeb qeeb kev txav mus los ntawm cov noob thiab tiv thaiv kev hloov pauv ntawm qhov kub siab.
3. Hmoov hlau metallurgy thiab kev sib xyaw ua ke
Kev siv hmoov hlau ua hlau yog qhov tseem ceeb vim nws tuaj yeem tsim cov qauv zoo los ntawm kos. Ib txoj kev tseem ceeb yog kev sib xyaw ua ke, uas yog ib qho txheej txheem milling uas siv zog ntau uas sib xyaw cov hmoov hlau, ua rau muaj kev hloov pauv ntau zaus, kev vuam txias, thiab kev tawg ua tej daim me me los ua cov hmoov nrog cov qauv zoo heev lossis ib feem tsis muaj zog. Cov hmoov no ces raug sintered lossis compacted (piv txwv li, los ntawm kev nias kub, HIP, lossis SPS) rau hauv cov khoom khov.
Nws cov txiaj ntsig suav nrog kev yooj ywm ntawm cov khoom sib xyaw (xws li cov hlau uas nyuaj rau tsim los ntawm kev yaj) thiab lub peev xwm los tsim cov nanostructures sib xws. Cov teeb meem suav nrog hmoov oxidation, kev ua qias tuaj ntawm cov khoom sib tsoo, thiab kev tswj porosity thaum lub sijhawm sintering.
4. Nanostructure txheej thiab kev tsim kho nto
Ntau daim ntawv thov xav tau kev ua haujlwm siab ntawm qhov chaw - xws li kev xeb thiab kev hnav tsis kam - yam tsis tas yuav hloov cov khoom siv tag nrho. Cov hlau nplaum saum npoo av muaj cov txheej txheem txheej txheem xws li PVD / CVD, electrodeposition, thermal spray, thiab modified nitriding thiab carburizing. Nanocrystalline coatings tuaj yeem ua rau kom muaj zog, txo qhov coefficient ntawm kev sib txhuam, thiab txhim kho kev tiv thaiv oxidation.
Tsis tas li ntawd xwb, kev tsim kho qhov chaw tso cai rau qhov sib txawv ntawm cov qauv: txheej sab nraud yog tawv heev (nanostructure), thaum lub plawv tseem ductile. Txoj hauv kev no tseem ceeb rau cov khoom siv kho tshuab xws li cov ncej, cov iav, thiab cov cuab yeej txiav.
Kev Txheeb Xyuas: xyuas kom meej tias cov nanostructures tau tsim tiag tiag
Kev tsim cov khoom siv nanostructured tsis tuaj yeem sib cais los ntawm cov txheej txheem kev piav qhia zoo heev. Metallurgy siv:
- SEM/TEM los soj ntsuam qhov loj ntawm cov noob, nanoprecipitates, thiab cov teeb meem siv lead ua.
- XRD los txheeb xyuas cov theem, cov kev ntxhov siab seem, thiab qhov loj ntawm crystallite.
- EBSD los kos duab qhia txog kev taw qhia siv lead ua thiab kev faib tawm ciam teb ntawm cov noob.
- APT (Atom Probe Tomography) los saib qhov kev faib tawm ntawm cov atoms thiab precipitates ntawm qhov atomic scale.
Yog tsis muaj kev piav qhia txog tus cwj pwm, cov txheej txheem tsuas yog "kev sim thiab qhov yuam kev." Nrog kev piav qhia txog tus cwj pwm, kev sib raug zoo ntawm cov txheej txheem-qauv-khoom vaj khoom tsev tuaj yeem raug kos duab thiab ua kom zoo dua.
Cov teeb meem tseem ceeb: kev ruaj khov ntawm thermal thiab kev lag luam
Txawm hais tias cov nanostructures muaj kev txhim kho zoo heev, muaj ob qhov teeb meem loj tshwm sim. Ua ntej yog qhov ruaj khov ntawm nanostructure. Cov noob me me heev muaj zog ciam teb noob siab; thaum cov khoom siv raug cua sov, cov noob feem ntau loj hlob, txo qhov muaj zog. Txhawm rau daws qhov no, metallurgy tau tsim cov tswv yim xws li kev ntxiv cov khoom sib xyaw uas tiv thaiv kev tsiv teb tsaws chaw ntawm cov noob, kev tsim cov precipitates uas "pin" cov ciam teb noob (Zener pinning), thiab kev tsim qauv meej ntawm cov voj voog kho cua sov.
Qhov kev sib tw thib ob yog qhov scalability. Ntau cov txheej txheem nanostructuring zoo heev hauv chav kuaj tab sis nyuaj rau siv rau kev tsim khoom loj vim yog tus nqi, tus nqi tsim khoom, lossis qhov txwv loj. Kev tshawb fawb tam sim no tsom mus rau kev ua kom cov txheej txheem sib xws nrog kev tsim khoom niaj hnub - suav nrog kev koom ua ke nrog kev tsim khoom ntxiv (hlau 3D luam ntawv) uas tuaj yeem tsim cov qauv me me zoo heev los ntawm kev txias siab, uas tom qab ntawd ruaj khov los ntawm kev kho cua sov ntxiv.
Cov ntawv thov: los ntawm kev thauj mus los mus rau lub zog thiab biomedicine
Cov ntaub ntawv nanostructured muaj peev xwm hloov pauv ntau yam kev lag luam. Hauv kev lag luam tsheb thiab aerospace, cov khoom siv nanostructured tuaj yeem txo qhov hnyav ntawm lub tsheb yam tsis muaj kev cuam tshuam rau lub zog thiab kev nyab xeeb. Hauv kev lag luam zog, cov ntaub ntawv ODS thiab lwm yam nanostructures yog qhov tseem ceeb rau kev siv kub siab, turbines, thiab cov khoom reactor. Hauv cov khoom siv hluav taws xob, nanolayers thiab cov qauv zoo tuaj yeem cuam tshuam rau kev coj ua thiab kev ntseeg tau ntawm kev sib txuas. Txawm tias hauv biomedicine, cov nplaim nanostructured ntawm cov implants tuaj yeem txhim kho kev sib koom ua ke ntawm cov ntaub so ntswg los ntawm kev tswj hwm qhov roughness thiab lub zog ntawm qhov chaw.
Kev kaw
Kev kawm txog hlau hauv kev tsim cov khoom siv nanostructured yog ib qho piv txwv zoo ntawm kev tshawb fawb qub txeeg qub teg hloov mus rau hauv thev naus laus zis yav tom ntej. Los ntawm kev tswj hwm kev sib xyaw, kev hloov pauv, kev kho cua sov, hmoov metallurgy, thiab cov txheej txheem tsim kho qhov chaw, cov kws tshawb fawb metallurgists muaj peev xwm "tsim qauv" cov qauv sab hauv mus rau nanoscale, tsim cov khoom siv nrog kev ua tau zoo yav dhau los tsis tau. Kev ruaj khov thiab kev tsim khoom loj tseem muaj, tab sis kev coj ntawm kev txhim kho yog qhov tseeb: cov khoom siv nanostructured yuav dhau los ua lub hauv paus tseem ceeb rau cov thev naus laus zis zoo dua, ruaj khov, thiab ruaj khov.
Yog tias koj xav tau, kuv tuaj yeem hloov kho tsab xov xwm no kom haum rau kev kawm ntau dua (nrog rau kev hais txog), lossis ntxiv cov ntu tshwj xeeb xws li nanograins vs. nanoprecipitates, kev sib raug zoo ntawm Hall-Petch, lossis cov ntaub ntawv kawm ntawm cov hlau tshwj xeeb (Al, Ti, Ni, hlau).
