Theem tsom xam cov txheej txheem pwm densification
Raws li lub ntsiab cai ntawm cov hmoov hlau metallurgy, qhov kub nias thiab sintering txheej txheem ntawm cov pob zeb diamond yog ib qho txheej txheem nrog rau kev diffusion, nchuav thiab lub cev thiab tshuaj lom neeg lub cev nyob rau hauv siab ceev ntawm kev kub.
Cov txheej txheem ntawm densification ntawm cov khoom (fetus) yuav muab faib ua peb theem:
1) theem ntawm kev ceev nrawm.Nyob rau hauv pwm, hmoov cov ntaub ntawv yeej yog nyob rau hauv lub xeev ntawm xoob loading. Nyob rau theem pib ntawm kub nias, qhov zis zis kuj, so thiab tawg deformation, thiab cov nqi qis yog siab. Nyob rau theem no, qhov kub siab pressing plays lub luag haujlwm tseem ceeb.
2) densification deceleration stage.Rau qhov kub nce siab, dej thiab lwm yam khoom tsis haum rau absorbed los ntawm cov pwm thiab hmoov ua tsis taus, thiab muaj coob tus cov phom sij uas maj mam tshwm rau ntawm cov hmoov av. Qhov ua kom siv rau hauv lub ntiaj teb ib qho me me ais txo, xws li npaj sintering cov tshuaj tiv thaiv no.Thaum qhov kub nce siab hauv qab tej lub ntsuas kub ntawm qhov nruab nrab ntawm qhov ua tiav theem, lub sij hawm tuav.
Ntawm qhov one hand, qhov tsis zoo ntawm kev kub ntxhov nyob hauv txhua qhov chaw ntawm lub pwm tuaj yeem ua kom haum, thiab qhov ntsuas kub tsis tshua muaj kub tsis muaj peev xwm tshem tau cov kev ntxhov siab hauv lub log tsheb.Thaum lwm sab tes, coob coob xws li kev tsis txaus siab, kev tsis tuaj yeem, kev nyuab siab, kev sib ntxub, thiab kev ua haujlwm sab nrauv hauv cov hmoov tawg yog tso tawm kom ua tiav rau kev sintering ntxiv. Nyob rau tib lub sij hawm, lub sij hawm ua kua ntau ntau ntawm cov hlau uas muaj kev sib txuas ntawm qhov chaw uas tsis tshua muaj melting yog tswj kom me ntsis nkag mus rau hauv lub xeev ua ntej tso.
3) ncav cuag qhov kawg qhov ceev theem nrog qhov kawg siab nce dua mus rau sintering kub, kua ntim ntau zog, hmoov lub cev nyob rau hauv qhov kev txiav txim ntawm kua deg nro txav mus rau permutation thiab ua ke nrog, vim los ntawm kev siv atomic vibration amplitude nce, diffusion , muaj ntau qhov atoms nyob rau hauv cov uas muaj atomic force rau hauv cov ntxhuav lis ciam kom tsawg grain interface, thiab nrog cov expansion ntawm grain interface, sintering siv tsub kom.