Zotsatira za Alloying Elements pa Makhalidwe a Makina a Zitsulo
Zitsulo zoyera sizigwiritsidwa ntchito kawirikawiri m'mafakitale omwe amafunikira mphamvu zambiri, kukana kuvala, kapena kulimba pansi pa mikhalidwe yovuta kwambiri. Mwachitsanzo, aluminiyamu yoyera ndi yopepuka komanso yosagwira dzimbiri, koma yofewa pang'ono. Chitsulo choyera chimatha kufewa, koma mphamvu zake zimakhala zochepa. Chifukwa chake, mafakitale nthawi zambiri amagwiritsa ntchito zitsulo zosungunulira, zomwe ndi zitsulo zoyambira zosakanikirana ndi zinthu zina m'njira inayake kuti akwaniritse kuphatikiza kwabwino kwa zinthu. Zinthu zowonjezerazi zimatchedwa zinthu zosungunulira, ndipo zimakhudza mphamvu zamakina—monga mphamvu yokoka, kuuma, kusinthasintha, kulimba, kukana kutopa, ndi kukana kuvala—ndizofunika kwambiri.
Lingaliro loyambira: chifukwa chiyani zinthu zophatikiza zimasintha mawonekedwe a makina?
Kapangidwe ka zitsulo kamatsimikiziridwa ndi kapangidwe kake kakang'ono: kukula kwa tirigu, mtundu ndi kuchuluka kwa magawo, kufalikira kwa ma precipitates, ndi kupezeka kwa zolakwika za kristalo monga kusuntha. Zinthu zosakaniza zimakhudza izi kudzera mu njira zingapo zofunika:
1. Kulimbitsa njira yolimba
Ma atomu a alloying element amatha kusintha ma atomu achitsulo choyambira (kusintha) kapena kudzaza mipata pakati pa ma atomu (interstitial). Kusiyana kwa kukula kwa atomu ndi mgwirizano wa mankhwala kumapangitsa kusokonekera kwa lattice komwe kumaletsa kusuntha kwa dislocation. Izi zimapangitsa kuti mphamvu ndi kuuma ziwonjezeke, koma kuchepa kwa ductility.
2. Kuuma kwa mvula (kuuma kwa ukalamba)
Mu zinthu zina zoyeretsera, kutentha kumapanga tinthu tating'onoting'ono tomwe timakhala ndi tinthu tating'onoting'ono (monga Al-Cu kapena Al-Mg-Si). Tinthu tating'onoting'ono timeneti timagwira ntchito ngati "chotchinga" kusuntha kwa zinthu, zomwe zimawonjezera mphamvu kwambiri.
3. Kulimbitsa kudzera mu mapangidwe a magawo olimba (monga carbides, nitrides, intermetallics)
Zinthu monga Cr, V, W, ndi Mo nthawi zambiri zimapanga ma carbide olimba mu chitsulo. Magawo olimba awa amawonjezera kuuma ndi kukana kuwonongeka, koma amatha kuchepetsa kulimba ngati alipo ochulukirapo kapena osagawidwa bwino.
4. Kukonza tirigu
Zinthu zina kapena njira zachitsulo zomwe zimakhudzidwa ndi zinthu zosakaniza zimatha kupanga tirigu wosalala. Mbewu zosalala nthawi zambiri zimawonjezera mphamvu ndi kulimba kwa zokolola.
5. Kusintha kwa chithunzi cha gawo ndi momwe kutentha kungachiritsidwire
Zinthu zosakaniza zimatha kukhazikika magawo ena, kusintha kutentha kwa kusintha, ndikuwonjezera kulimba. Mwachitsanzo, mu chitsulo, kuwonjezera kwa zinthu zina kumalola martensite kupanga ngakhale kuzizira sikuli kofulumira kwambiri.
Zotsatira za alloying zinthu pa chitsulo: zitsanzo zazikulu kwambiri
Chitsulo ndiye njira yodziwika bwino ya alloy, makamaka chifukwa kusintha pang'ono kwa zinthu zomwe zili muzinthu kungapangitse kusiyana kwakukulu kwa mawonekedwe a makina.
1. Mpweya (C)
Mpweya wa kaboni ndiye chinthu chofunikira kwambiri chopangira zitsulo. Umawonjezera mphamvu ndi kuuma kudzera mu kupanga simenti (Fe₃C) komanso kuthekera kopanga martensite pambuyo pouma.
– Mphamvu ndi kuuma: kumawonjezeka ndi kuchuluka kwa C m'thupi.
– Kulimba mtima ndi kulimba: nthawi zambiri kumachepa pamene C ili pamwamba kwambiri.
– Kukana kuvala: kuwonjezeka chifukwa cha gawo lolimba kwambiri.
Chitsulo chopanda mpweya woipa chimakhala cholimba kwambiri komanso chosavuta kuchilumikiza, pomwe chitsulo chopanda mpweya woipa chimakhala cholimba koma chophwanyika mosavuta.
2. Manganese (Mn)
Manganese imawonjezera mphamvu kudzera mu yankho lolimba ndipo imathandiza kumangirira sulfure kupanga MnS (kuchepetsa kutentha pang'ono).
– Mphamvu ndi kulimba: kuwonjezeka.
– Kulimba: kumatha kuwonjezeka pamlingo wapakati, koma pamlingo wapamwamba kuwongolera kapangidwe ka zinthu kumafunika.
3. Chromium (Cr)
Chrome imadziwika kwambiri ndi chitsulo chosapanga dzimbiri, komanso imagwiritsidwa ntchito kwambiri chifukwa cha mphamvu zake komanso kukana kuwonongeka.
– Kukana kuvala ndi kuuma: kumawonjezeka chifukwa cha kupangika kwa ma carbide olimba a Cr.
– Kulimba: kuwonjezeka, zomwe zimapangitsa kuti magawo opingasa akhale olimba.
– Kukana dzimbiri: kumawonjezeka kwambiri ngati kuli kokwanira (nthawi zambiri ≥ ~ 10,5% mu chosapanga dzimbiri) chifukwa cha kupangika kwa Cr₂O₃ wosanjikiza wosanjikiza.
– Ngozi: ma carbide ochulukirapo amatha kuchepetsa kulimba.
4. Nikeli (Ni)
Nickel ndi chinthu chabwino kwambiri chowonjezera kulimba, makamaka kutentha kochepa.
– Kulimba ndi kusinthasintha: kumawonjezeka, kumathandiza kupewa kusweka kwa mafupa.
– Mphamvu: imawonjezeka pamene ikusunga kulimba bwino.
- Kugwiritsa ntchito: Chitsulo cha Ni alloy cha zombo, matanki a cryogenic ndi zida zina zomwe zimafuna kulimba kwambiri.
5. Molybdenum (Mo)
Molybdenum imagwiritsidwa ntchito kwambiri pa kutentha kwambiri komanso kukana kufewa.
– Mphamvu pa kutentha kwakukulu: kuwonjezeka (kukana kukwawa bwino).
– Kulimba: kuwonjezeka.
- Kukana kuzizira: Mo ingathandize kuchepetsa kuzizira pambuyo pa kutentha kwina.
6. Vanadium (V), Niobium (Nb), Titanium (Ti)
Zinthu zosakaniza izi zimagwira ntchito ngakhale zitakhala zochepa. Zimapanga ma carbide/nitrides abwino ndikuyeretsa tirigu.
– Mphamvu yobereka: imawonjezeka kwambiri kudzera mu kusungunuka bwino kwa nthaka ndi kukonzedwa kwa tirigu.
- Kulimba mtima: kungakhalebe bwino ngati kuwongolera njira kuli koyenera.
- Kugwiritsa ntchito: Chitsulo cha HSLA (High Strength Low Alloy) cha nyumba.
7. Silikoni (Si)
Silicon ndi deoxidizer yodziwika bwino komanso imalimbitsa mayankho olimba.
– Mphamvu: yawonjezeka.
– Kukana okosijeni: kumawonjezeka pansi pa mikhalidwe ina.
– Zindikirani: kuchuluka kwa Si kungakhudze kusinthasintha kwa kapangidwe kake ndi luso lake lopanga.
Zotsatira za kuphatikiza zinthu pa aluminiyamu
Aluminiyamu imayankha bwino kwambiri mvula ikagwa. Chifukwa chake, chinthu chachikulu chopangira alloying, Al, chimapangidwa kuti chipange ma precipitates abwino kudzera mu mankhwala ndi ukalamba.
– Mkuwa (Cu): umawonjezera mphamvu zambiri (2xxx series) kudzera mu mvula, koma kukana dzimbiri kungachepe.
– Magnesium (Mg): imawonjezera mphamvu ndi kukana dzimbiri; pamodzi ndi Si imapanga Mg₂Si (mndandanda wa 6xxx) womwe umagwirizanitsa mphamvu ndi kuthekera kokonza.
– Zinc (Zn) + Mg (ndipo nthawi zambiri Cu): imapanga ma alloys amphamvu kwambiri (7xxx series), otchuka mumlengalenga, koma zinthu zina zimakhala zosavuta kusweka ndi stress corrosion cracking (SCC) ndipo zimafuna kulamulira kutentha ndi chitetezo.
– Silicon (Si): imathandiza kuponya ndipo, ndi Mg, imathandizira mvula.
Mu aluminiyamu, mphamvu yowonjezera nthawi zambiri "imalipidwa" ndi kuchepa kwa ductility, komanso kukhudzidwa ndi dzimbiri m'zinthu zina.
Zotsatira za kuphatikiza zinthu pa mkuwa ndi titaniyamu (mwachidule)
Mu zitsulo zamkuwa, kuwonjezera kwa Zn (mkuwa) kumawonjezera mphamvu ndi kuthekera kokonza, pomwe Sn (mkuwa) kumawonjezera kukana kuwonongeka ndi kukana dzimbiri. Komabe, zinthu zambiri zophatikizana nthawi zambiri zimachepetsa mphamvu zamagetsi/kutentha—kuchepa kwakukulu kwa zigawo zamagetsi.
Mu titaniyamu, zinthu monga Al zimakhazikitsa gawo la alpha, pomwe V ndi Mo zimakhazikitsa gawo la beta. Titaniyamu ya Alpha-beta (monga Ti-6Al-4V) imapereka kuphatikiza kwa mphamvu yayikulu, kulimba, komanso kukana dzimbiri, yokhala ndi mphamvu yochepa. Kapangidwe ka titaniyamu kamadalira kwambiri magawo omwe adapangidwa komanso chithandizo cha kutentha.
Ubale pakati pa zinthu zophatikiza ndi zinthu zazikulu zamakanika
Nayi chidule cha maubwenzi omwe amakumana nawo nthawi zambiri:
– Mphamvu yokoka/kutulutsa: nthawi zambiri imawonjezeka ndi yankho lolimba, mvula, tirigu wosalala, ndi magawo olimba.
– Kulimba: kumawonjezeka ndi martensite (mu chitsulo), precipitates, ndi carbides/nitrides.
– Kulimba: nthawi zambiri kumachepa pamene mphamvu/kulimba kumawonjezeka, koma zinthu monga Ni zimatha kusunga kulimba.
- Kulimba kwa mphamvu: kutengera kukula kwa tirigu, kufalikira kwa gawo lolimba, ndi kupezeka kwa zinthu zomwe zaphatikizidwa; Ni ndi kukonzanso tirigu nthawi zambiri zimathandiza.
– Kukana kutopa: kumawonjezeka ndi kapangidwe kake kamene kali kofanana, kuphatikiza pang'ono, komanso mphamvu yowonjezereka; komabe, kuphulika kwa makoma/ming'alu yaying'ono kumatha kuipiraipira.
– Kukana kuvala: kumawonjezeka ndi ma carbide olimba, martensite komanso kuuma bwino pamwamba.
Kutseka
Zinthu zopangira aloyi ndi "zida zofunika kwambiri" muukadaulo wa zitsulo pokonza mawonekedwe a zitsulo kuti zigwirizane ndi zosowa za ntchito. Posankha mtundu ndi kuchuluka kwa zinthu, kenako kuwongolera njira monga kutentha, kuzimitsa, ndi kuwongolera kapangidwe ka zinthu, mainjiniya amatha kupanga zinthu zopepuka koma zolimba, zolimba koma zolimba, kapena zosawonongeka ndipo zimagwira ntchito kutentha kwambiri. Komabe, kusintha kulikonse kwa zinthu nthawi zambiri kumabwera ndi kusinthana: mphamvu yowonjezera ikhoza kuchepetsa kusinthasintha, kulimbitsa mvula kumatha kuwonjezera chiopsezo cha dzimbiri, ndipo magawo olimba amatha kuchepetsa kulimba ngati sikulamulidwa. Chifukwa chake, kapangidwe ka aloyi nthawi zonse kumakhala koyenera pakati pa kapangidwe, njira, ndi magwiridwe antchito amunda.
