Kev Txheeb Xyuas Txog Tshuab thiab Cov Qauv ntawm Cov Hlau Alloys
Pendahuluuan
Cov hlau sib xyaw yog cov khoom siv uas tsim los ntawm kev sib xyaw ob lossis ntau yam khoom - tsawg kawg yog ib qho yog hlau - kom tau txais cov khoom zoo dua li cov hlau ntshiab. Cov piv txwv feem ntau yog hlau (Fe-C), tooj dag (Cu-Zn), thiab txhuas sib xyaw (Al nrog Mg, Si, Cu, lossis Zn). Hauv kev siv hauv kev lag luam, cov hlau sib xyaw raug xaiv rau lawv cov khoom sib xyaw xws li lub zog siab, kev tawv, kev tiv thaiv corrosion, thiab yooj yim ntawm kev tsim khoom. Rau kev siv cov hlau sib xyaw no kom raug thiab muaj kev nyab xeeb, lawv cov yam ntxwv kho tshuab thiab cov qauv yog qhov tsim nyog. Cov yam ntxwv no pab piav qhia txog kev sib raug zoo ntawm microstructure (piv txwv li, qhov loj me ntawm cov noob, theem, precipitates, thiab cov khoom siv lead ua tsis zoo) thiab kev coj cwj pwm kho tshuab (piv txwv li, lub zog tensile, hardness, ductility, thiab kev tiv thaiv qaug zog).
Cov Ntsiab Lus Tseem Ceeb ntawm Cov Qauv Hlau Alloy
Cov qauv ntawm cov hlau alloys feem ntau yog tham txog ntawm ntau qhov ntsuas:
1. Atomic scale/crystallography: kev teeb tsa ntawm cov atoms hauv ib lub crystal lattice (FCC, BCC, HCP).
2. Qhov ntsuas me me: qhov loj ntawm cov noob, ciam teb ntawm cov noob, theem, nag los, cov khoom suav nrog, porosity.
3. Qhov ntsuas loj: kev sib cais, qhov tsis zoo ntawm kev casting, cov kab nrib pleb, thiab cov qauv uas tshwm sim los ntawm cov txheej txheem tsim.
Qhov sib txawv ntawm theem (piv txwv li, ferrite thiab pearlite hauv cov hlau carbon) cuam tshuam rau cov khoom siv kho tshuab. Ntxiv mus, cov txheej txheem kho cua sov xws li annealing, quenching, thiab tempering tuaj yeem hloov pauv theem faib thiab hloov pauv qhov loj ntawm cov noob, yog li hloov cov khoom siv lub zog thiab kev tawv. Yog li ntawd, kev piav qhia txog cov qauv yog qhov tseem ceeb rau kev nkag siab txog cov txiaj ntsig ntawm kev sim kho tshuab.
Kev Txheeb Xyuas Txog Lub Tshuab: Cov Hom Phiaj thiab Cov Txheej Txheem Tseem Ceeb
Kev piav qhia txog lub cev yog los ntsuas qhov teb ntawm cov khoom siv rau cov khoom thauj tshwj xeeb, kev hloov pauv, thiab cov xwm txheej ib puag ncig. Cov kev ntsuas feem ntau suav nrog:
1. Kev Ntsuas Tensile
Qhov kev sim tensile yog txoj hauv kev tseem ceeb rau kev tau txais cov kab nkhaus kev ntxhov siab. Los ntawm qhov kev sim no, cov hauv qab no tuaj yeem txiav txim siab tau:
- Lub zog tawm los: qhov txwv uas cov khoom pib muaj kev hloov pauv yas mus tas li.
– Lub zog tensile kawg (UTS): kev ntxhov siab siab tshaj plaws ua ntej lub caj dab tshwm sim.
- Kev ncab: lub peev xwm ntawm cov khoom siv kom ncab ua ntej tawg.
- Modulus ntawm elasticity (Young's modulus): qhov tawv ntawm cov khoom siv hauv thaj chaw elastic.
Cov hlau sib xyaw nrog cov precipitates me me (piv txwv li Al-Cu alloys) feem ntau ua rau muaj zog ntxiv vim tias cov precipitates tiv thaiv kev txav mus los.
2. Kev Ntsuas Qhov Nyuaj
Kev sim qhov nyuaj sai thiab siv tau los kwv yees qhov tsis kam ntawm cov khoom siv rau kev nkag mus lossis kev hloov pauv hauv zos. Cov txheej txheem feem ntau:
– Brinell: tsim nyog rau cov ntaub ntawv mos mos mus rau nruab nrab thiab tsis yog cov qauv zoo heev.
- Rockwell: ceev, siv dav hauv kev lag luam.
– Vickers thiab Micro-Vickers: siv tau los ntsuas qhov nyuaj hauv thaj chaw me me, suav nrog qee theem hauv microstructure.
Qhov nyuaj feem ntau muaj feem cuam tshuam nrog lub zog tensile hauv ntau cov alloys, txawm hais tias qhov kev sib raug zoo no xav tau kev kho kom raug raws li hom khoom siv thiab kev kho cua sov.
3. Kev Ntsuas Kev Cuam Tshuam
Kev ntsuam xyuas kev cuam tshuam xws li Charpy lossis Izod ntsuas lub zog uas cov khoom siv nqus thaum raug kev cuam tshuam. Cov txheej txheem no tseem ceeb rau kev ntsuam xyuas qhov tawv thiab qhov tawg yooj yim, tshwj xeeb tshaj yog hauv cov hlau uas tuaj yeem hloov pauv brittle-ductile vim muaj kev hloov pauv kub. Cov qauv noob zoo dua thiab cov theem ductile ntau dua feem ntau ua rau muaj kev tawv.
4. Kev Ntsuas Kev Qaug Zog
Cov khoom siv engineering xws li cov ncej, cov iav, cov caij nplooj ntoos hlav, thiab cov qauv dav hlau feem ntau raug rau cov khoom thauj rov ua dua. Kev ntsuam xyuas qaug zog tsim cov kab nkhaus S-N (kev ntxhov siab piv rau tus lej ntawm cov voj voog kom tawg). Cov yam ntxwv cuam tshuam rau qaug zog suav nrog:
- qhov roughness ntawm qhov chaw,
- muaj cov qhov me me los yog cov qhov hws,
- kev ntxhov siab seem,
- ib puag ncig corrosive,
- thiab microstructure (qhov loj ntawm cov noob, nag lossis daus, thiab kev faib tawm theem).
Cov hlau nplaum uas muaj cov khoom loj lossis cov porosity siab feem ntau muaj lub neej qaug zog qis dua vim tias cov kab nrib pleb yooj yim pib ntawm cov qhov tsis zoo no.
5. Kev Ntsuas Kev Tawg thiab Kev Nyuaj Siab
Thaum muaj qhov kub siab (piv txwv li, cov cav roj, cov boilers, lossis cov reactors), cov ntaub ntawv tuaj yeem hloov pauv qeeb qeeb (creep) ntev. Kev ntsuam xyuas creep ntsuas qhov nrawm piv rau lub sijhawm ntawm qhov kev ntxhov siab thiab kub tshwj xeeb. Lub tshuab creep yog cuam tshuam los ntawm atomic diffusion, cov ciam teb ntawm cov noob, thiab kev ruaj khov theem. Cov superalloys nickel-based yog tsim los kom muaj precipitates xws li γ 'ruaj khov ntawm qhov kub siab kom txhim kho kev tiv thaiv creep.
Kev Txheeb Xyuas Cov Qauv: Cov Txheej Txheem thiab Cov Ntaub Ntawv Tau Txais
Kev piav qhia txog cov qauv lub hom phiaj yog los soj ntsuam thiab ntsuas cov yam ntxwv sab hauv ntawm cov hlau sib xyaw. Cov txheej txheem suav nrog:
1. Metallography (Kev Siv Tshuab Microscopy)
Metallography yog thawj kauj ruam hauv kev kawm txog microstructure. Cov qauv raug txiav, nias, xuab zeb, txhuam, thiab tom qab ntawd etched siv cov tshuaj lom neeg los qhia cov noob thiab cov ciam teb theem. Qhov no tso cai rau kev tshuaj xyuas ntawm:
- qhov loj ntawm cov noob,
– feem pua theem,
– kev faib tawm ntawm pearlite / ferrite hauv hlau,
- dendrites nyob rau hauv cov hlau cam khwb cia,
- nrog rau qhov tsis zoo hauv daim ntawv ntawm porosity lossis micro cracks.
Qhov loj ntawm cov noob feem ntau muaj feem cuam tshuam nrog lub zog los ntawm kev sib raug zoo ntawm Hall-Petch: cov noob me dua, lub zog tso zis siab dua (txog qee qhov txwv).
2. Kev Siv Lub Tshuab Hluav Taws Xob (Electron Microscope) (SEM) thiab Kev Tshawb Fawb Txog Cov Khoom Siv (EDS)
Lub Tshuab Ntsuas Hluav Taws Xob (SEM) muab kev daws teeb meem siab dua li lub tshuab ntsuas hluav taws xob thiab muaj txiaj ntsig zoo rau:
- saib cov morphology ntawm cov nag thiab theem,
– soj ntsuam cov qhov tawg (fractography),
- soj ntsuam cov txheej txheem tawg (ductile, brittle, intergranular).
SEM feem ntau yog ua ke nrog Energy Dispersive Spectroscopy (EDS) rau kev tshuaj xyuas cov ntsiab lus hauv zos, piv txwv li txheeb xyuas cov sulfur-nplua nuj suav nrog hauv cov hlau lossis tooj liab-nplua nuj precipitates hauv cov hlau txhuas.
3. Kev Siv Hluav Taws Xob X-ray Diffraction (XRD)
X-ray diffraction (XRD) yog siv los txheeb xyuas cov theem crystalline thiab cov lattice parameters. XRD pab:
- nrhiav cov theem uas nyuaj rau paub qhov txawv ntawm metallographically,
- ntsuas kev ntxhov siab seem,
- kev soj ntsuam cov qauv siv lead ua,
- thiab kwv yees qhov loj ntawm crystallite hauv cov ntaub ntawv zoo heev.
Hauv hlau, XRD tuaj yeem paub qhov txawv ntawm ferrite, retained austenite, thiab martensite los ntawm cov qauv diffraction.
4. TEM (Kev Siv Tshuab Hluav Taws Xob Xa Mus Los)
Rau kev soj ntsuam nanometer-scale, TEM yog qhov tseem ceeb, tshwj xeeb tshaj yog rau cov alloys uas tau precipitation-strengthened lossis raug rau deformation loj heev. TEM muaj peev xwm tso saib:
- kev tawg thiab cov pob txha subgrain,
- nanoprecipitate,
- kev puas tsuaj ntawm cov stacking,
- nrog rau cov ciam teb theem du heev.
Cov ntaub ntawv no tseem ceeb heev rau cov hlau niaj hnub xws li cov txhuas uas tawv tau ntev, cov hlau martensitic, lossis cov hlau titanium rau cov ntawv thov aerospace.
5. Kev Ntsuas Tsis Ua Rau Puas Tsuaj (NDT)
Hauv kev siv hauv kev lag luam, kev txheeb xyuas cov qauv tsis tas yuav tsum tau rhuav tshem cov khoom. Cov txheej txheem NDT suav nrog:
- kev kuaj mob ultrasound los nrhiav cov teeb meem sab hauv,
- kev thaij duab hluav taws xob (X-ray/gamma) rau qhov porosity thiab kab nrib pleb,
- cov khoom sib nqus rau cov qhov tsis zoo ntawm qhov chaw hauv cov hlau ferromagnetic,
- xim nkag mus rau qhov tawg ntawm ntau yam hlau.
NDT yog qhov tseem ceeb rau kev tswj xyuas zoo thiab kev tshuaj xyuas tsis tu ncua ntawm kev tsim kho tseem ceeb.
Kev sib raug zoo ntawm Microstructure thiab Mechanical Properties
Kev sib raug zoo ntawm cov qauv thiab khoom yog lub hauv paus ntawm kev tshawb fawb txog cov ntaub ntawv. Qee qhov piv txwv ntawm cov kev sib raug zoo no yog:
- Cov dej nag me me ua rau lub zog (cov dej nag tawv) tab sis tuaj yeem txo qhov ductility yog tias ntau dhau.
- Cov noob me me ua rau lub zog thiab feem ntau yog tawv, tab sis qee cov txheej txheem tuaj yeem ua rau muaj kev ntxhov siab ntxiv.
- Cov theem tawv xws li martensite ua rau kom tawv thiab muaj zog ntxiv, tab sis tuaj yeem txo qhov tawv yog tias tsis tau tempered.
- Cov khoom suav nrog thiab porosity feem ntau txo qhov kev tiv taus qaug zog thiab kev tawv vim tias lawv ua rau muaj kab nrib pleb.
Yog li ntawd, kev txhais lus ntawm cov txiaj ntsig ntawm kev sim tshuab yuav tsum txuas nrog cov txiaj ntsig ntawm kev tshuaj xyuas cov qauv kom nkag siab txog qhov ua rau muaj tus cwj pwm ntawm cov khoom siv, tsis yog tsuas yog sau tseg xwb.
Kev kaw
Kev piav qhia txog cov khoom siv thiab cov qauv ntawm cov hlau sib xyaw yog ib qho tseem ceeb ntawm cov haujlwm kom ntseeg tau tias cov ntaub ntawv ua tau raws li kev tsim qauv thiab kev nyab xeeb. Kev ntsuam xyuas tshuab xws li tensile, hardness, impact, qaug zog, thiab creep muab cov ntaub ntawv ntau ntawm kev ua tau zoo ntawm cov khoom siv hauv qab ntau yam kev thauj khoom. Lub caij no, kev piav qhia txog cov qauv los ntawm metallography, SEM / EDS, XRD, TEM, thiab NDT piav qhia "vim li cas" cov ntaub ntawv qhia txog qee yam khoom los ntawm kev qhia txog cov theem, qhov loj me ntawm cov noob, cov av noo, kev tawg, thiab cov qhov tsis zoo sab hauv. Kev sib xyaw ua ke ntawm cov no tso cai rau kev ua kom zoo dua ntawm cov khoom sib xyaw, kev kho cua sov, thiab cov txheej txheem tsim khoom, tso cai rau kev tsim cov khoom sib xyaw txhim khu kev qha rau cov ntawv thov xws li kev tsim kho thiab tsheb mus rau aerospace thiab lub zog.
Yog tias koj xav tau, kuv tuaj yeem kho tsab xov xwm no kom luv dua 1000 lo lus (raws nraim 1000), lossis tsom mus rau ib qho hlau tshwj xeeb xws li hlau, txhuas, titanium, lossis nickel superalloys.
