Annealing da quenching da tsufa su ne asali na zafi magani nau'i na aluminum gami. Annealing magani ne mai laushi, wanda manufarsa shine sanya kayan haɗin gwal da kwanciyar hankali a cikin abun da ke ciki da tsari, kawar da taurin aiki, da mayar da filastik na gami. Quenching da tsufa magani ne mai ƙarfafa zafi, wanda manufarsa ita ce inganta ƙarfin gami, kuma ana amfani da shi musamman don kayan aikin aluminum waɗanda za a iya ƙarfafa su ta hanyar maganin zafi.
1 Annealing
Dangane da buƙatun samarwa daban-daban, annealing alloy aluminium ya kasu kashi da yawa: ingot homogenization annealing, billet annealing, matsakaici annealing da ƙãre samfurin annealing.
1.1 Ingot homogenization annealing
Karkashin yanayin daɗaɗɗa da sauri da rashin daidaituwar crystallization, ingot ɗin dole ne ya kasance da tsari da tsari mara daidaituwa, kuma yana da babban damuwa na ciki. Domin canza wannan halin da ake ciki da kuma inganta zafi aiki processability na ingot, homogenization annealing ne kullum ake bukata.
Domin inganta atomic diffusion, ya kamata a zabi mafi girma zafin jiki don homogenization annealing, amma dole ne ba wuce low narkewa batu eutectic narkewa batu na gami. Kullum, da homogenization annealing zafin jiki ne 5 ~ 40 ℃ m fiye da narkewa batu, da kuma annealing lokaci ne mafi yawa tsakanin 12 ~ 24h.
1.2 Billet annealing
Billet annealing yana nufin ɓarnawa kafin nakasar sanyi ta farko yayin sarrafa matsi. Manufar ita ce a sa billet ɗin ya sami daidaitaccen tsari kuma yana da matsakaicin ƙarfin nakasar filastik. Misali, da mirgina karshen zafin jiki na zafi-birgima aluminum gami slab ne 280 ~ 330 ℃. Bayan saurin sanyaya a dakin da zafin jiki, ba za a iya kawar da matsalar taurin aikin gaba ɗaya ba. Musamman, don ƙarfin da aka yi amfani da shi na aluminum gami da zafi mai zafi, bayan saurin sanyaya, tsarin recrystallization bai ƙare ba, kuma ba a rushe ingantaccen bayani mai ƙarfi ba, kuma wani ɓangare na aikin hardening da quenching sakamako har yanzu yana riƙe. Yana da wahala a yi sanyi mirgine kai tsaye ba tare da annashuwa ba, don haka ana buƙatar annealing billet. Don abubuwan da ba a kula da su ba da ƙarfi na aluminium, irin su LF3, zafin jiki na annealing shine 370 ~ 470 ℃, kuma ana yin sanyaya iska bayan kiyaye dumi don 1.5 ~ 2.5h. Matsakaicin zafin jiki da zafin jiki da ake amfani da shi don sarrafa bututu mai sanyi ya kamata su kasance mafi girma yadda ya kamata, kuma ana iya zaɓar mafi girman iyaka. Domin aluminum gami da za a iya ƙarfafa ta zafi magani, kamar LY11 da LY12, da billet annealing zafin jiki ne 390 ~ 450 ℃, kiyaye a wannan zafin jiki for 1 ~ 3h, sa'an nan sanyaya a cikin tanderun zuwa kasa 270 ℃ a wani kudi na ba fiye da 30 ℃ / h sa'an nan iska-sanyi fita daga cikin tanderun.
1.3 Matsakaici annealing
Tsakanin tsaka-tsaki yana nufin ɓarna tsakanin matakan nakasar sanyi, wanda manufarsa ita ce kawar da taurin aiki don sauƙaƙe ci gaba da nakasar sanyi. Gabaɗaya magana, bayan an cire kayan, zai zama da wahala a ci gaba da aikin sanyi ba tare da annashuwa na tsaka-tsaki ba bayan jurewa 45 ~ 85% nakasar sanyi.
Tsarin aiwatar da matsakaita annealing daidai yake da na cire billet. Bisa ga bukatun sanyi nakasawa digiri, matsakaici annealing za a iya raba uku iri: cikakken annealing (total nakasawa ε≈60 ~ 70%), sauki annealing (ε≤50%) da kuma kadan annealing (ε≈30 ~ 40%). Na farko biyu annealing tsarin iri daya ne da billet annealing, kuma na karshen yana mai tsanani a 320 ~ 350 ℃ for 1.5 ~ 2h sa'an nan iska sanyaya.
1.4. Ƙarshen annealing samfurin
Ƙarshen shafewar samfurin shine maganin zafi na ƙarshe wanda ke ba kayan wasu ƙayyadaddun tsari da na inji bisa ga buƙatun yanayin fasaha na samfur.
Za a iya raba shafewar da aka gama zuwa yanayin zafi mai zafi (samar da samfurori masu laushi) da ƙananan zafin jiki (samar da samfurori masu wuyar gaske a cikin jihohi daban-daban). Babban zafin jiki annealing ya kamata a tabbatar da cewa za a iya samun cikakken recrystallization tsarin da kuma mai kyau roba. A ƙarƙashin yanayin tabbatar da cewa kayan sun sami tsari mai kyau da aiki, lokacin riƙewa bai kamata ya yi tsayi da yawa ba. Don allunan aluminium waɗanda za a iya ƙarfafa su ta hanyar maganin zafi, don hana tasirin sanyayawar iska, yakamata a sarrafa ƙimar sanyaya sosai.
Ƙarƙashin zafin jiki ya haɗa da kwantar da hankali na damuwa da raguwa mai laushi, wanda aka fi amfani da shi don tsantsar aluminium da marasa zafi da aka ƙarfafa aluminum gami. Ƙirƙirar tsarin ƙaddamar da ƙananan zafin jiki aiki ne mai wuyar gaske, wanda ba kawai yana buƙatar la'akari da zafin jiki na annealing da kuma riƙe lokaci ba, amma kuma yana buƙatar la'akari da tasirin ƙazanta, digiri na alloy, nakasar sanyi, matsakaicin zafi mai zafi da zafi na nakasawa. Don tsara tsarin ƙananan zafin jiki na ƙananan zafin jiki, yana da mahimmanci don auna ma'auni na canji tsakanin zafin jiki na annealing da kayan aikin injiniya, sa'an nan kuma ƙayyade yawan zafin jiki na annealing bisa ga alamun aikin da aka ƙayyade a cikin yanayin fasaha.
2 Quenching
The quenching na aluminum gami kuma ana kiransa maganin maganin, wanda shine narkar da abubuwa masu yawa a cikin ƙarfe a matsayin kashi na biyu a cikin ingantaccen bayani kamar yadda zai yiwu ta hanyar dumama zafi mai zafi, sannan saurin sanyaya don hana hazo na kashi na biyu, ta haka samun ingantaccen bayani mai ƙarfi na aluminum na tushen α, wanda aka shirya sosai don maganin tsufa na gaba.
Dalili na samun babban bayani mai ƙarfi na α mai ƙarfi shine cewa solubility na kashi na biyu a cikin gami a cikin aluminum ya kamata ya karu sosai tare da karuwar zafin jiki, in ba haka ba, ba za a iya cimma manufar ingantaccen maganin maganin ba. Yawancin abubuwa masu haɗawa a cikin aluminium na iya ƙirƙirar zane na eutectic tare da wannan sifa. Shan Al-Cu gami a matsayin misali, da eutectic zafin jiki ne 548 ℃, da kuma dakin zafin jiki solubility na jan karfe a aluminum ne kasa da 0.1%. Lokacin da mai tsanani zuwa 548 ℃, ta solubility yana ƙaruwa zuwa 5.6%. Saboda haka, Al-Cu alloys dauke da kasa da 5.6% jan karfe shiga α guda lokaci yankin bayan dumama zafin jiki ya wuce da solvus line, wato, kashi na biyu CuAl2 ne gaba daya narkar da a cikin matrix, da kuma guda supersaturated α m bayani za a iya samu bayan quenching.
Quenching shine aiki mafi mahimmanci kuma mafi buƙatar aikin maganin zafi don kayan haɗin aluminum. Makullin shine don zaɓar zafin zafin da ya dace na kashe wutar lantarki da tabbatar da isassun yanayin sanyaya, da kuma sarrafa zafin tanderu sosai da rage nakasar kashewa.
Ka'idar zaɓin zafin jiki na quenching shine ƙara yawan zafin jiki mai zafi kamar yadda zai yiwu yayin da tabbatar da cewa aluminum gami ba ta ƙonewa ba ko hatsi suna girma da yawa, don ƙara haɓakar α m bayani da ƙarfi bayan tsufa magani. Gabaɗaya, tanderun dumama na aluminium yana buƙatar daidaiton zafin wutar lantarki ya kasance tsakanin ± 3 ℃, kuma ana tilasta iskar da ke cikin tanderu don yaduwa don tabbatar da daidaiton zafin wutar tanderun.
Konewar gami da aluminium yana faruwa ne ta hanyar narkewar sassa na ƙananan abubuwan da ke narkewa a cikin ƙarfe, kamar binary ko eutectics na abubuwa da yawa. Ƙarfafawa ba kawai yana haifar da raguwar kayan aikin injiniya ba, amma har ma yana da tasiri mai tsanani akan juriya na lalata. Don haka, da zarar abin da aka yi amfani da shi na aluminum ya ƙone, ba za a iya kawar da shi ba kuma ya kamata a soke samfurin da aka yi da shi. Ainihin yawan zafin jiki mai zafi na aluminum gami an ƙaddara shi ta hanyar abun ciki na gami da ƙazanta, kuma yana da alaƙa da yanayin sarrafa gami. Yawan zafin jiki na samfuran da aka yi aikin nakasar filastik ya fi na simintin gyaran kafa. Mafi girman sarrafa nakasar, yana da sauƙi don waɗanda ba a daidaita ƙananan abubuwan da ake narkewa ba su narke cikin matrix lokacin da aka yi zafi, don haka ainihin zafin jiki mai zafi yana ƙaruwa.
Adadin sanyaya a lokacin quenching na aluminum gami yana da tasiri mai mahimmanci akan ƙarfin ƙarfafa tsufa da juriya na lalata. A lokacin quenching tsari na LY12 da LC4, shi wajibi ne don tabbatar da cewa α m bayani ba bazu, musamman a cikin zafin jiki m yankin na 290 ~ 420 ℃, da kuma isasshe babban sanyaya kudi ake bukata. Yawancin lokaci an kayyade cewa sanyaya kudi ya zama sama da 50 ℃ / s, kuma ga LC4 gami, ya kamata kai ko wuce 170 ℃ / s.
Mafi yawan amfani da quenching matsakaici don aluminum gami shine ruwa. Ayyukan samarwa yana nuna cewa mafi girman adadin sanyaya yayin quenching, mafi girman ragowar damuwa da ragowar nakasar kayan da aka kashe ko kayan aiki. Saboda haka, ga kananan workpieces da sauki siffofi, da ruwa zafin jiki na iya zama dan kadan m, kullum 10 ~ 30 ℃, kuma kada ya wuce 40 ℃. Don workpieces tare da hadaddun siffofi da manyan bambance-bambance a cikin bango kauri, domin rage quenching nakasawa da fatattaka, da ruwa zafin jiki na iya wani lokacin za a iya ƙara zuwa 80 ℃. Duk da haka, dole ne a nuna cewa yayin da yawan zafin jiki na ruwa na tanki mai kashewa ya karu, ƙarfin da juriya na lalata na kayan yana raguwa daidai.
3. Tsufa
3.1 Canjin tsari da canje-canjen aiki yayin tsufa
Magani mai ƙarfi na α mai ƙarfi da aka samu ta hanyar quenching tsari ne mara ƙarfi. Lokacin da zafi, zai rube kuma ya zama tsarin ma'auni. Ɗaukar Al-4Cu alloy a matsayin misali, tsarin ma'auni ya kamata ya zama α+CuAl2 (θ lokaci). Lokacin da ingantaccen bayani mai ƙarfi na lokaci-ɗaya bayan quenching ya yi zafi don tsufa, idan zafin jiki ya isa sosai, lokacin θ zai haɓaka kai tsaye. In ba haka ba, za a gudanar da shi a matakai, wato, bayan wasu matakan tsaka-tsaki na tsaka-tsaki, za a iya kai ga matakin ma'auni na ƙarshe na CuAl2. Hoton da ke ƙasa yana kwatanta sifofin tsarin kristal na kowane matakin hazo yayin aikin tsufa na Al-Cu gami. Hoto a. shine tsarin lattice crystal a cikin yanayin da aka kashe. A wannan lokacin, bayani ne mai ƙarfi mai ƙarfi na α guda-ɗaya, kuma atom ɗin jan ƙarfe (dige-dige baƙar fata) ana rarraba su daidai da ka'ida a cikin aluminum (dige fari) matrix lattice. Hoto b. yana nuna tsarin lattice a farkon matakin hazo. Atom ɗin jan ƙarfe sun fara tattara hankali a wasu wurare na matrix lattice don samar da yankin Guinier-Preston, wanda ake kira yankin GP. Yankin GP yana da ƙanƙanta sosai kuma mai siffar diski, tare da diamita na kusan 5 ~ 10μm da kauri na 0.4 ~ 0.6nm. Yawan yankunan GP a cikin matrix yana da girma sosai, kuma yawan rarraba zai iya kaiwa 10¹⁷~10¹⁸cm-³ . Tsarin lu'ulu'u na yankin GP har yanzu iri ɗaya ne da na matrix, duka biyun cubic ne na fuskar fuska, kuma yana kiyaye haɗin kai tare da matrix. Duk da haka, saboda girman atom ɗin tagulla ya yi ƙasa da na atom ɗin aluminum, haɓakar atom ɗin tagulla zai haifar da raguwar lattice ɗin crystal kusa da yankin, wanda ke haifar da murdiya.
Zane-zane na tsarin kristal yana canzawa na Al-Cu gami yayin tsufa
Hoto a. Yanayin da aka kashe, bayani mai ƙarfi na lokaci-lokaci α, atom ɗin jan ƙarfe (dige baƙar fata) ana rarraba su daidai gwargwado;
Hoto b. A farkon matakin tsufa, an kafa yankin GP;
Hoto c. A cikin ƙarshen mataki na tsufa, an kafa wani lokaci na tsaka-tsakin tsaka-tsaki;
Hoto d. Babban yawan tsufa, hazo na lokacin ma'auni mara daidaituwa
Yankin GP shine samfurin farko na hazo wanda ke bayyana yayin aikin tsufa na gami da aluminium. Tsawaita lokacin tsufa, musamman ƙara yawan zafin jiki, zai kuma samar da wasu matakan tsaka-tsaki. A cikin Al-4Cu alloy, akwai matakan θ” da θ’ bayan yankin GP, kuma a ƙarshe an kai ma’aunin ma’auni CuAl2. θ” da θ’ duka matakan miƙa mulki ne na θ lokaci, kuma tsarin kristal shi ne lattice mai murabba’i, amma tsattsauran ra’ayi ya bambanta. Girman θ ya fi na yankin GP girma, har yanzu yana da siffar diski, tare da diamita na kusan 15 ~ 40nm da kauri na 0.8 ~ 2.0nm. Yana ci gaba da kiyaye haɗin haɗin gwiwa tare da matrix, amma matakin karkatar da lattice ya fi tsanani. Lokacin canzawa daga θ" zuwa θ' lokaci, girman ya girma zuwa 20 ~ 600nm, kauri shine 10 ~ 15nm, kuma haɗin haɗin haɗin gwiwar kuma an lalatar da shi a wani ɓangare, ya zama haɗin haɗin kai, kamar yadda aka nuna a cikin Hoto c. Samfurin ƙarshe na hazo mai girma shine ma'auni na lokaci θ (wanda ba shi da lokaci-lokaci kuma ba ya zama lokaci-lokaci) ya zama lokaci-lokaci ba tare da lalacewa ba. dubawa, kamar yadda aka nuna a hoto d.
Dangane da yanayin da ke sama, tsarin tsufa na Al-Cu alloy shine αs→α+GP zone →α+θ”→α+θ'→α+θ.Matakin tsarin tsufa ya dogara da ƙayyadaddun gami da ƙayyadaddun tsufa.Sau da yawa ana samun samfuran tsufa fiye da ɗaya a cikin jihar guda.
A lokacin tsarin tsufa, yankin GP da lokacin canji da aka haɗe daga matrix ƙananan girma ne, tarwatse sosai, kuma ba su da sauƙi. A lokaci guda kuma, suna haifar da ɓarna a cikin matrix kuma suna samar da filin damuwa, wanda ke da tasiri mai mahimmanci a kan motsi na raguwa, don haka ƙara juriya ga lalata filastik na gami da inganta ƙarfinsa da taurinsa. Wannan al'amari na taurin tsufa ana kiran hazo hardening. Hoton da ke ƙasa yana kwatanta canjin taurin alloy na Al-4Cu yayin quenching da maganin tsufa a cikin nau'i na lankwasa. Mataki na I a cikin adadi yana wakiltar taurin gami a cikin ainihin yanayinsa. Saboda tarihin aiki mai zafi daban-daban, taurin asalin jihar zai bambanta, gabaɗaya HV=30 ~ 80. Bayan dumama a 500 ℃ da quenching (mataki II), duk jan karfe zarra suna narkar da a cikin matrix don samar da wani lokaci-lokaci supersaturated α m bayani tare da HV = 60, wanda shi ne sau biyu da wuya kamar taurin a cikin annealed jihar (HV=30). Wannan shi ne sakamakon ƙarfafa ƙarfi mai ƙarfi. Bayan quenching, an sanya shi a dakin da zafin jiki, kuma taurin gami yana ci gaba da ƙaruwa saboda ci gaba da samuwar GP zones (mataki III). Wannan tsarin taurin tsufa a yanayin zafin jiki ana kiransa tsufa na halitta.
I—halin asali;
II - m yanayin bayani;
III-tsufa na halitta (yankin GP);
IVa-maganin farfadowa a 150 ~ 200 ℃ (sake narkar da shi a yankin GP);
IVb — tsufa na wucin gadi (θ”+θ' lokaci);
V — overaging (θ”+θ' lokaci)
A mataki na IV, ana yin zafi da gawa zuwa 150 ° C don tsufa, kuma tasirin taurin ya fi bayyane fiye da na tsufa na halitta. A wannan lokacin, samfurin hazo shine mafi yawan lokaci na θ ", wanda ke da tasiri mafi girma a cikin Al-Cu alloys. Idan yawan zafin jiki ya kara karuwa, lokacin hazo yana canzawa daga lokaci na θ" zuwa θ 'lokacin, tasirin hardening yana raunana, kuma taurin yana raguwa, shigar da mataki V. Duk wani maganin tsufa da ke buƙatar wucin gadi da IV, ana kiran wannan nau'i na wucin gadi. Idan taurin ya kai matsakaicin ƙimar taurin da gawa zai iya kaiwa bayan tsufa (watau mataki IVb), ana kiran wannan tsufa kololuwar tsufa. Idan kololuwar darajar taurin ba ta kai ba, ana kiranta rashin tsufa ko rashin cika tsufa na wucin gadi. Idan an ƙetare ƙimar kololuwar kuma taurin ya ragu, ana kiran shi fiye da tsufa. Gyaran yanayin tsufa shima yana cikin yawan tsufa. Yankin GP da aka kafa yayin tsufa na halitta ba shi da kwanciyar hankali. Lokacin zafi da sauri zuwa mafi girman zafin jiki, kamar kusan 200 ° C, kuma ana yin dumi na ɗan gajeren lokaci, yankin GP zai narke baya cikin α ƙwaƙƙwaran bayani. Idan aka yi saurin sanyi (quenched) kafin sauran matakan canji kamar θ” ko θ' hazo, za a iya dawo da alloy ɗin zuwa yanayin da ya mutu na asali.
Ƙarfafawar shekaru shine tushen haɓakar abubuwan da ake amfani da su na aluminium mai zafi, kuma ƙarfin ƙarfin shekarunsa yana da alaƙa kai tsaye da haɗin gwal da tsarin kula da zafi. Al-Si da Al-Mn na binary alloys ba su da tasiri mai taurin hazo saboda lokacin ma'auni yana haɗe kai tsaye yayin tsarin tsufa, kuma alloys na aluminium mara zafi. Ko da yake Al-Mg gami na iya samar da yankunan GP da matakan canji β', kawai suna da takamaiman iyawar hazo a cikin gami da manyan abubuwan magnesium. Al-Cu, Al-Cu-Mg, Al-Mg-Si da Al-Zn-Mg-Cu alloys suna da ƙarfin ƙarfin hazo mai ƙarfi a cikin yankunan GP ɗin su da matakan miƙa mulki, kuma a halin yanzu sune manyan tsarin gami waɗanda za a iya magance zafi da ƙarfafawa.
3.2 Tsufa ta Halitta
Gabaɗaya, allunan aluminum waɗanda za a iya ƙarfafa su ta hanyar maganin zafi suna da tasirin tsufa na halitta bayan quenching. Ƙarfafa tsufa na halitta yana haifar da yankin GP. Ana amfani da tsufa na halitta ko'ina a cikin Al-Cu da Al-Cu-Mg gami. Tsufa na al'ada na Al-Zn-Mg-Cu alloys yana daɗe da yawa, kuma sau da yawa yana ɗaukar watanni da yawa don isa matakin kwanciyar hankali, don haka ba a amfani da tsarin tsufa na halitta.
Idan aka kwatanta da tsufa na wucin gadi, bayan tsufa na dabi'a, ƙarfin yawan amfanin ƙasa yana da ƙasa, amma filastik da taurin sun fi kyau, kuma juriya na lalata ya fi girma. Halin super-hard aluminum na tsarin Al-Zn-Mg-C ya ɗan bambanta. Juriya na lalata bayan tsufa na wucin gadi ya fi kyau fiye da haka bayan tsufa na halitta.
3.3 tsufa na wucin gadi
Bayan maganin tsufa na wucin gadi, allunan aluminium sau da yawa na iya samun ƙarfin yawan amfanin ƙasa (yawanci ƙarfafa lokaci mai ƙarfi) da ingantaccen kwanciyar hankali na ƙungiya. Super-hard aluminum, jabun aluminium da simintin aluminium galibi tsufa ne na wucin gadi. Yawan zafin jiki na tsufa da lokacin tsufa suna da tasiri mai mahimmanci akan abubuwan gami. Yawan zafin jiki na tsufa yana tsakanin 120 ~ 190 ℃, kuma lokacin tsufa baya wuce 24h.
Baya ga tsufa na wucin gadi-ɗaki-daki, gami da aluminium na iya ɗaukar tsarin tsufa na wucin gadi. Wato ana yin dumama sau biyu ko fiye a yanayin zafi daban-daban. Alal misali, LC4 gami za a iya shekaru a 115 ~ 125 ℃ for 2 ~ 4h, sa'an nan a 160 ~ 170 ℃ for 3 ~ 5h. Gradual tsufa iya ba kawai muhimmanci gajarta lokaci, amma kuma inganta microstructure na Al-Zn-Mg da Al-Zn-Mg-Cu gami, da kuma muhimmanci inganta danniya lalata juriya, gajiya ƙarfi da karaya tauri ba tare da m rage na inji Properties.
Lokacin aikawa: Maris-06-2025
