Cov yam ntxwv ua haujlwm iav

1. Isotropic
Cov txheej txheem molecular ntawm iav yog qhov tsis sib xws, thiab nws cov molecules yog qhov sib txawv hauv qhov chaw. Nyob rau hauv lub xeev zoo tagnrho, lub cev thiab tshuaj lom neeg cov khoom ntawm homogeneous iav (xws li refractive index, hardness, elastic modulus, thermal expansion coefficient, thermal conductivity, hluav taws xob conductivity, thiab lwm yam) yog tib yam nyob rau hauv tag nrho cov lus qhia.
2. Tsis tas li melting point
Vim tias iav yog qhov sib xyaw thiab tsis yog crystalline, nws tsis muaj cov ntsiab lus melting thiab boiling. Kev hloov ntawm iav los ntawm cov khoom mus rau cov kua yog tshwm sim nyob rau hauv ib tug tej yam kub ntau yam (piv txwv li, softening kub ntau yam). Tsis zoo li cov khoom siv crystalline, nws tsis muaj qhov ntsuas kub ruaj khov. Qhov kub ntawm qhov muag yog Tg ~ T1, Tg yog qhov hloov pauv kub, T1 yog cov kua dej kub, thiab cov viscosities sib thooj yog 10^13.4dPa· thiab 10^4~6dPa·s raws.
3. Metastability
Cov khoom iav feem ntau tau txais los ntawm kev ua kom txias sai sai ntawm melts. Thaum hloov los ntawm lub xeev molten mus rau lub xeev glassy, ​​lub viscosity nce sharply thaum lub sij hawm txias. Cov khoom tsis muaj sij hawm los npaj lawv tus kheej tsis tu ncua los tsim cov muaju, thiab cov cua sov latent ntawm crystallization tsis tso tawm. Yog li ntawd, lub xeev glassy Cov Khoom muaj lub zog sab hauv ntau dua li cov khoom siv crystalline, thiab lawv lub zog nyob nruab nrab ntawm lub xeev molten thiab lub xeev crystallized, thiab yog lub xeev metastable. Los ntawm ib qho kev xav ntawm txhua yam, iav yog lub zog tsis ruaj khov. Piv txwv li, muaj ib tug nyiam hloov mus rau hauv lub xeev uas tsis muaj zog, uas yog, muaj ib tug nyiam mus crystallize. Yog li ntawd, iav yog cov khoom siv metastable.
4. Gradient thim rov qab
Cov txheej txheem ntawm cov khoom siv iav los ntawm lub xeev molten mus rau lub xeev cov khoom yog maj mam, thiab cov kev hloov hauv lawv lub cev thiab tshuaj lom neeg kuj tseem txuas ntxiv thiab maj mam. Qhov no yog pom tseeb txawv ntawm cov txheej txheem crystallization ntawm yaj, qhov twg ib theem tshiab yuav inevitably tshwm sim, thiab ntau yam khoom yuav raug hloov tam sim ntawd nyob ze ntawm qhov kub ntawm crystallization. Kev hloov pauv ntawm cov khoom siv iav los ntawm lub xeev molten mus rau lub xeev tau ua tiav nyob rau hauv qhov kub thiab txias. Raws li qhov kub thiab txias maj mam txo qis, cov viscosity ntawm cov iav yaj maj mam nce, thiab thaum kawg cov iav yog tsim, tab sis tsis muaj cov theem tshiab tsim thaum lub sij hawm txheej txheem. Ntawm qhov tsis sib xws, cov txheej txheem ntawm cov iav cua sov rau hauv yaj kuj maj mam.