Cov khoom siv fiber ntau ceramic feem ntau yog siv los ua cov khoom siv engineering ntawm qhov kub siab tshaj 1000 degree, thiab lawv cov creep kuj plays lub luag haujlwm tseem ceeb hauv cov txheej txheem kub kub ntawm qhov cub. Yog li ntawd, kev tshawb fawb ntawm cov ntaub ntawv tsis tshua muaj creep refractory tau txais kev saib xyuas ntxiv.
Kev ua haujlwm siab kub ntawm cov khoom siv fiber ntau refractory feem ntau yog nyob ntawm cov yam ntxwv ntawm microstructure thiab ob yam tseem ceeb: qhov ntau thiab viscosity ntawm iav matrix (iav nyhuv), nrog rau qib thiab hom kev sib cuag lossis kev sib txuas ntawm cov muaju (crystal). effect). Cov ntsiab lus qis ntawm iav theem, siab viscosity, thiab qib siab ntawm intergranular bonding tsim ib qho kev txuas txuas txuas txuas txuas ntxiv, uas yog qhov tsim nyog rau kev txhim kho cov khoom siv hluav taws xob kub.
High-temperature creep theory
Creep yog feem ntau hu ua creep deformation, uas txhais tau hais tias nyob rau hauv lub mechanical kev nyuaj siab nyob rau hauv lub yield point, cov khoom undergoes ntws thiab loj hloov mus rau lub sij hawm, thaum nws txoj kev ncaj ncees tsis puas. Qhov no deformation qhia tau hais tias cov khoom muaj peev xwm tiv taus txhua yam loads ntev. Lub creep nkhaus yog ib qho nkhaus uas tsis tu ncua hloov cov deformation ntawm cov khoom nyob rau lub sij hawm nyob rau hauv qhov kub thiab txias thiab load tsis tu ncua.
Nws tuaj yeem muab faib ua peb theem: (1) Kev hloov pauv hloov pauv tshwm sim thaum pib thauj khoom, ε Creep tus nqi yog 0 d ε / D t=ξ Txo theem (tseem hu ua deceleration lossis migration creep stage) ; (2) Steady state creep theem nrog yam tsawg kawg nkaus thiab qhov nkag mus tas li; (3) Lub creep tus nqi nce sharply mus txog rau thaum theem ntawm nce creep tus nqi ua ntej tsis ua hauj lwm (tseem hu ua lub accelerated creep theem).
Cov yam ntxwv cuam tshuam rau cov creep kuj ntawm ceramics fibers
Muaj ntau ntau yam uas cuam tshuam rau qhov kub-kub creep ntawm ceramic fibers, ntau qhov sib cuam tshuam. Lub ntsiab yam tseem ceeb cuam tshuam rau cov creep deformation ntawm ceramic fibers yog raws li nram no: lwm yam kev mob, xws li kub, load, lub sij hawm, cua (oxidation los yog txo), cov khoom zoo, nrog rau nws cov tshuaj muaj pes tsawg leeg, ntxhia muaj pes tsawg leeg (ib theem lossis multiphase), thiab microstructure. Cov tshuaj ntxhia muaj pes tsawg leeg thiab microstructure ntawm ceramic fibers txiav txim siab lawv cov creep kuj.