Kev soj ntsuam ntawm Microstructure ntawm cov ntaub ntawv nyob rau hauv ib qho Optical
Raws li lawv cov yam ntxwv ntawm cov qauv thiab cov ntsiab lus carbon, hlau-carbon alloys tuaj yeem muab faib ua peb pawg: muaj hlau ntshiab, hlau thiab cam khwb cia hlau. Cov hlau ntshiab muaj tsawg dua 0.0218 wt% C. Hlau-carbon alloys nrog cov ntsiab lus carbon qis dua 2.11 wt% txhais tau tias yog hlau, thiab alloys nrog cov ntsiab lus carbon siab tshaj 2.11 wt% yog cam khwb cia hlau.
Nyob rau hauv chav tsev kub, lub microstructures ntawm carbon steel thiab dawb cam khwb cia hlau muaj ob theem tseem ceeb: ferrite (F) thiab cementite (Fe₃C). Qhov sib txawv ntawm cov ntsiab lus carbon hloov cov nyiaj txheeb ze, nag lossis daus thiab kev faib tawm ntawm ferrite thiab cementite, ua rau muaj ntau yam microstructural morphologies.
Ferrite yog ib qho kev daws teeb meem ntawm cov pa roj carbon nyob rau hauv-hlau, txhais los ntawm lub cim "F". Ferrite muaj equiaxed nplej nrog lub cev-centered cubic crystal lattice.
Cementite yog ib qho intermetallic compound ntawm hlau thiab carbon, denoted los ntawm "Fe₃C". Cementite tuaj yeem muaj nyob hauv ntau hom nyob ntawm nws qhov muaj pes tsawg leeg thiab tsim cov xwm txheej.
Pearlite yog kev sib xyaw ua ke ntawm ferrite thiab cementite, txhais los ntawm "P". Nyob rau hauv ib txwm annealing tej yam kev mob, nws yog ib tug lamellar qauv tsim los ntawm alternating txheej ntawm ferrite thiab cementite.
Etching ntawm cov hlau ntshiab thiab ib-theem alloys yog txheej txheem tshuaj lom neeg. Thaum cov qauv polished los rau hauv kev sib cuag nrog etchant, deformed cuam tshuam txheej ntawm polished nto yog yaj ua ntej, thaum lub microstructure ntawm cov hlau tseem tsis tau tshwm sim. Qhov no yog ua raws li kev nyiam tshuaj lom neeg tawg ntawm cov ciam teb nplej. Qhov tsis xwm yeem atomic kev npaj ntawm cov ciam teb yog corroded sai heev los ua grooves, nthuav tawm cov nplej ntau ntau ntawm cov hlau. Yog hais tias etching txuas ntxiv, lub etchant kuj tawm tsam cov nplej sab hauv. Vim tias qhov sib xyaw ua ke sib txawv ntawm cov nplej, txhua cov nplej nthuav tawm cov dav hlau atomic dav dav tom qab etching. Nyob rau hauv ntsug illumination, cov nplej qhia txawv brightness.
Etching ntawm ob-theem alloys feem ntau yog cov txheej txheem electrochemical. Cov theem sib txawv ntawm cov khoom sib txawv thiab cov qauv muaj qhov sib txawv ntawm cov electrode, tsim ntau cov galvanic me me hauv zos hauv etchant. Ferrite ua raws li cov anode nrog lub peev xwm ntau dua electrode thiab yaj thaum lub sij hawm etching, tshwm sim nyuaj siab thiab ntxhib. Cementite ua haujlwm raws li cathode nrog lub peev xwm zoo thiab tsis tshua muaj kev tawm tsam. Nyob rau hauv lub optical microscope, ferrite tshwm tsaus nti thiab cementite zoo li ci dawb.
