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Insimbi engu-20MnTiB iyinto esetshenziswa kakhulu ngamabholidi aqinile kakhulu emabhulohweni esakhiwo sensimbi ezweni lakithi, futhi ukusebenza kwayo kubaluleke kakhulu ekusebenzeni okuphephile kwamabhuloho. Ngokusekelwe ocwaningweni lwendawo ezungezile eChongqing, lolu cwaningo lwaklama ikhambi lokugqwala elilingisa isimo sezulu esinomswakama saseChongqing, futhi lwenza ukuhlolwa kokugqwala kokucindezeleka kwamabholidi anamandla aphezulu elingisa isimo sezulu esinomswakama saseChongqing. Imiphumela yokushisa, inani le-pH kanye nokuhlushwa kwekhambi lokugqwala elilingisiwe ekuziphatheni kokugqwala kokucindezeleka kwamabholidi anamandla aphezulu angu-20MnTiB kwafundwa.
Insimbi ye-20MnTiB iyinto esetshenziswa kakhulu ngamabholidi aqinile kakhulu emabhulohweni esakhiwo sensimbi ezweni lakithi, futhi ukusebenza kwayo kubaluleke kakhulu ekusebenzeni okuphephile kwamabhuloho. ULi et al. 1 bahlole izakhiwo zensimbi ye-20MnTiB evame ukusetshenziswa kumabholidi aqinile ebanga le-10.9 ebangeni lokushisa eliphakeme elingu-20 ~ 700 ℃, futhi bathola ijika lokucindezeleka, amandla okukhiqiza, amandla okudonsa, i-modulus kaYoung, kanye ne-elongation. kanye ne-expansion coefficient. UZhang et al. 2, Hu et al. 3, njll., ngokuhlolwa kokwakheka kwamakhemikhali, ukuhlolwa kwempahla yemishini, ukuhlolwa kwe-microstructure, ukuhlaziywa kwe-macroscopic kanye ne-microscopic ebusweni bentambo, futhi imiphumela ikhombisa ukuthi isizathu esiyinhloko sokuphuka kwamabholidi anamandla aphezulu sihlobene nokukhubazeka kwentambo, kanye nokuvela kokukhubazeka kwentambo Ukugxila okukhulu kokucindezeleka, ukugxila kokucindezeleka kwe-crack tip kanye nezimo zokugqwala emoyeni ovulekile konke kuholela ekuqhekekeni kokucindezeleka.
Amabhawodi anamandla aphezulu amabhuloho ensimbi avame ukusetshenziswa isikhathi eside endaweni enomswakama. Izinto ezifana nomswakama ophezulu, izinga lokushisa eliphezulu, kanye nokuthungwa kanye nokumuncwa kwezinto eziyingozi endaweni kungabangela kalula ukugqwala kwezakhiwo zensimbi. Ukugqwala kungabangela ukulahlekelwa kwezingxenye zebhawodi enamandla aphezulu, okuholela ezifweni eziningi kanye nokuqhekeka. Futhi la maphutha kanye nokuqhekeka kuzoqhubeka nokukhula, ngaleyo ndlela kunciphisa impilo yamabhawodi anamandla aphezulu futhi kubangele nokuthi aphuke. Kuze kube manje, kunezifundo eziningi ngomphumela wokugqwala kwemvelo ekusebenzeni kokugqwala kokucindezeleka kwezinto. UCatar et al4 baphenye ukuziphatha kokugqwala kokucindezeleka kwama-alloy e-magnesium anokuqukethwe okuhlukile kwe-aluminium ezindaweni ezine-acidic, alkaline kanye ne-neutral ngokuhlolwa kwesilinganiso sokucindezeleka okuhamba kancane (SSRT). U-Abdel et al.5 bafunde ukuziphatha kokugqwala kokucindezeleka kwe-electrochemical kanye ne-stress kwe-Cu10Ni alloy kusisombululo se-NaCl esingu-3.5% lapho kukhona amazinga ahlukene ama-ion e-sulfide. U-Aghion et al.6 bahlole ukusebenza kokugqwala kwe-die-cast magnesium alloy MRI230D kusisombululo se-NaCl esingu-3.5% ngokuhlolwa kokucwiliswa, ukuhlolwa kwe-salt spray, ukuhlaziywa kwe-potentiodynamic polarization kanye I-SSRT.Zhang nabanye.7 bafunde ukuziphatha kokugqwala kokucindezeleka kwensimbi ye-martensitic engu-9Cr besebenzisa i-SSRT kanye namasu okuhlola e-electrochemical endabuko, futhi bathola umphumela wama-ion e-chloride ekuziphatheni kokugqwala okungaguquki kwensimbi ye-martensitic ekushiseni kwegumbi. UChen nabanye.8 bahlole ukuziphatha kokugqwala kokucindezeleka kanye nendlela yokuqhekeka kwensimbi ye-X70 esixazululweni sodaka lolwandle esilingisiwe esiqukethe i-SRB emazingeni okushisa ahlukene yi-SSRT. ULiu nabanye.9 basebenzise i-SSRT ukutadisha umphumela wokushisa kanye nesilinganiso sokucindezeleka kokucindezeleka ekumelaneni nokugqwala kokucindezeleka kwamanzi olwandle kwensimbi engagqwali engu-00Cr21Ni14Mn5Mo2N. Imiphumela ikhombisa ukuthi izinga lokushisa eliphakathi kuka-35~65℃ alinawo umthelela omkhulu ekuziphatheni kokugqwala kokucindezeleka kwensimbi engagqwali. ULu nabanye. 10 bahlole ukuthambekela kokuphuka okulibazisekile kwamasampula anamazinga ahlukene okuqina kokuthambekela ngokuhlolwa kokuphuka okulibazisekile komthwalo ofile kanye ne-SSRT. Kuphakanyiswa ukuthi amandla okuthambekela kwama-bolts ensimbi angu-20MnTiB kanye nama-bolts ensimbi angu-35VB kufanele alawulwe ku-1040-1190MPa. Kodwa-ke, iningi lalezi zifundo ngokuyisisekelo zisebenzisa isisombululo esilula esingu-3.5% NaCl ukulingisa indawo egqwalisayo, kuyilapho indawo yokusetshenziswa kwangempela kwama-bolts anamandla aphezulu iyinkimbinkimbi kakhulu futhi inezici eziningi ezithonya, njengenani le-pH le-bolt. U-Ananya et al. 11 bafunde umphumela wamapharamitha emvelo nezinto zokwakha endaweni egqwalisayo ekuqhekekeni kokugqwala kanye nokuqhekeka kokugqwala kwezinsimbi ezingenalutho ezimbili. USunada et al. 12 benze izivivinyo zokuqhekeka kokugqwala kokucindezeleka kokushisa kwegumbi ensimbini ye-SUS304 ezixazululweni zamanzi eziqukethe i-H2SO4 (0-5.5 kmol/m-3) kanye ne-NaCl (0-4.5 kmol/m-3). Imiphumela ye-H2SO4 kanye ne-NaCl ezinhlotsheni zokugqwala zensimbi ye-SUS304 nayo yafundwa. UMerwe et al.13 basebenzise i-SSRT ukutadisha imiphumela yokujika, izinga lokushisa, ukuhlushwa kwe-CO2/CO, ingcindezi yegesi kanye nesikhathi sokugqwala ekuthambekeni kokugqwala kokucindezeleka kwensimbi ye-A516 pressure vessel. Besebenzisa isixazululo se-NS4 njengesixazululo sokulingisa amanzi angaphansi komhlaba, u-Ibrahim et al. 14 baphenya umphumela wamapharamitha ezemvelo njengokuhlushwa kwe-bicarbonate ion (HCO), i-pH kanye nokushisa ekuqhekekeni kokugqwala kokucindezeleka kwensimbi yepayipi le-API-X100 ngemva kokukhipha i-coating. UShan et al. 15 bafunde umthetho wokwehluka kokuthambekela kokugqwala kokucindezelwa kwensimbi engagqwali ye-austenitic 00Cr18Ni10 enezinga lokushisa ngaphansi kwezimo zokushisa ezahlukene (30~250℃) ngaphansi kwesimo sendawo yamanzi amnyama esitshalweni samalahle esilingisiwe yi-SSRT. UHan et al.16 bachaze ukuthambekela kokugqwala kwe-hydrogen kwamasampula e-bolt anamandla aphezulu besebenzisa isivivinyo sokuqhekeka okulibazisekile komthwalo kanye ne-SSRT. UZhao17 bafunde imiphumela ye-pH, SO42-, Cl-1 ekuziphatheni kokugqwala kokucindezelwa kwe-GH4080A alloy yi-SSRT. Imiphumela ikhombisa ukuthi uma inani le-pH liphansi, ukumelana kokugqwala kokucindezelwa kwe-GH4080A alloy kuba kubi kakhulu. Inozwela lokugqwala kokucindezelwa okusobala ku-Cl-1, futhi ayizweli ku-SO42-ionic medium ekushiseni kwegumbi. Kodwa-ke, kunezifundo ezimbalwa ngomphumela wokugqwala kwemvelo kuma-bolts ensimbi angu-20MnTiB aphezulu.
Ukuze kutholakale izizathu zokwehluleka kwamabholthi anamandla aphezulu asetshenziswa emabhulohweni, umbhali wenze uchungechunge lwezifundo. Kukhethwe amasampula amabholthi anamandla aphezulu, futhi izizathu zokwehluleka kwala masampula zaxoxwa ngazo kusukela emibonweni yokwakheka kwamakhemikhali, isimo se-fracture microscopic, isakhiwo se-metallographic kanye nokuhlaziywa kwezakhiwo zemishini19, 20. Ngokusekelwe ophenyweni lwendawo ezungezile eChongqing eminyakeni yamuva nje, kuklanywe uhlelo lokugqwala olulingisa isimo sezulu esinomswakama saseChongqing. Ukuhlolwa kokugqwala kokucindezeleka, ukuhlolwa kokugqwala kwe-electrochemical kanye nokuhlolwa kokukhathala kokugqwala kwamabholthi anamandla aphezulu eChongqing okulingisa isimo sezulu esinomswakama kwenziwa. Kulolu cwaningo, imiphumela yokushisa, inani le-pH kanye nokuhlushwa kwesisombululo sokugqwala esilingisiwe ekuziphatheni kokugqwala kokucindezeleka kwamabholthi anamandla aphezulu angu-20MnTiB kuhlolwe ngokuhlolwa kwezakhiwo zemishini, ukuhlaziywa kwe-fracture macroscopic kanye ne-microscopic, kanye nemikhiqizo yokugqwala komhlaba.
I-Chongqing itholakala eningizimu-ntshonalanga yeShayina, indawo ephezulu yoMfula iYangtze, futhi inesimo sezulu esinomswakama semvula engaphansi kwezindawo ezishisayo. Izinga lokushisa elijwayelekile lonyaka lingu-16-18°C, isilinganiso somswakama sonyaka ikakhulukazi singama-70-80%, amahora okukhanya kwelanga ngonyaka angamahora ayi-1000-1400, kanti iphesenti lokukhanya kwelanga lingu-25-35% kuphela.
Ngokusho kwemibiko ehlobene nokukhanya kwelanga kanye nokushisa okuzungezile eChongqing kusukela ngo-2015 kuya ku-2018, izinga lokushisa elijwayelekile lansuku zonke eChongqing liphansi njengo-17°C futhi liphakeme njengo-23°C. Izinga lokushisa eliphakeme kakhulu emzimbeni webhuloho leChaotianmen Bridge eChongqing lingafinyelela ku-50°C °C21,22. Ngakho-ke, amazinga okushisa okuhlolwa kokugqwala kokucindezeleka abekwe ku-25°C kanye no-50°C.
Inani le-pH lesisombululo sokugqwala esilingisiwe linquma ngqo inani le-H+, kodwa akusho ukuthi uma inani le-pH liphansi, ukugqwala kulula kakhulu. Umphumela we-pH emiphumeleni uzohluka ezintweni ezahlukene kanye nezixazululo. Ukuze kufundwe kangcono umphumela wesisombululo sokugqwala esilingisiwe ekusebenzeni kokugqwala kokucindezeleka kwama-bolts anamandla aphezulu, amanani e-pH okuhlolwa kokugqwala kokucindezeleka abekwe ku-3.5, 5.5 kanye no-7.5 ngokuhlanganiswa nocwaningo lwezincwadi23 kanye nobubanzi be-pH bamanzi emvula waminyaka yonke eChongqing.2010 kuya ku-2018.
Uma ukuhlushwa kwesisombululo sokugqwala esilingisiwe kuphakeme, okuqukethwe kwe-ion okuningi esixazululweni sokugqwala esilingisiwe, kanye nethonya elikhulu ezimpahleni zezinto ezibonakalayo. Ukuze kufundwe umphumela wokuhlushwa kwesisombululo sokugqwala esilingisiwe ekugqwaleni kokucindezeleka kwama-bolts anamandla aphezulu, ukuhlolwa kokugqwala okusheshisiwe kwelabhorethri yokwenziwa kwaqashelwa, futhi ukuhlushwa kwesisombululo sokugqwala esilingisiwe kwasethwa ezingeni lesi-4 ngaphandle kokugqwala, okwakuyi-concentration yokuqala yesisombululo sokugqwala esilingisiwe (1×), ukuhlushwa kwesisombululo sokugqwala esilingisiwe esingu-20 × (20 ×) kanye nokuhlushwa kwesisombululo sokugqwala esilingisiwe esingu-200 × (200 ×).
Indawo enezinga lokushisa elingu-25℃, inani le-pH elingu-5.5, kanye nokuhlushwa kwesisombululo sokuqala sokugqwala esilingisiwe kuseduze kakhulu nezimo zokusetshenziswa zangempela zamabholidi anamandla aphezulu amabhuloho. Kodwa-ke, ukuze kusheshiswe inqubo yokuhlola ukugqwala, izimo zokuhlola ezinezinga lokushisa elingu-25 °C, i-pH engu-5.5 kanye nokuhlushwa kwesisombululo sokuqala sokugqwala esilingisiwe esingu-200 × kwabekwa njengeqembu lokulawula okubhekiselwe kulo. Lapho imiphumela yokushisa, ukuhlushwa noma inani le-pH yesisombululo sokugqwala esilingisiwe ekusebenzeni kokugqwala kokucindezeleka kwamabholidi anamandla aphezulu ihlolwa ngokulandelana, ezinye izici azizange zishintshe, ezasetshenziswa njengezinga lokuhlola leqembu lokulawula okubhekiselwe kulo.
Ngokusho kwesitatimende sekhwalithi yezemvelo somoya sango-2010-2018 esakhishwa yi-Chongqing Municipal Bureau of Ecology and Environment, futhi sibhekisela ezingxenyeni zemvula ezibikwe ku-Zhang24 kanye neminye imibhalo ebikwe ku-Chongqing, kwaklanywa isisombululo sokugqwala esilingisiwe esisekelwe ekwandiseni ukugcwala kwe-SO42-. Ukwakheka kwemvula endaweni enkulu yasemadolobheni yaseChongqing ngo-2017. Ukwakheka kwesisombululo sokugqwala esilingisiwe kuboniswe kuThebula 1:
Isixazululo sokugqwala esilingisiwe silungiswa ngendlela yokulinganisela ukuhlushwa kwama-ion amakhemikhali kusetshenziswa ama-reagent okuhlaziya kanye namanzi acwengekile. Inani le-pH lesisombululo sokugqwala esilingisiwe lilungiswe ngemitha ye-pH enembile, isixazululo se-nitric acid kanye nesisombululo se-sodium hydroxide.
Ukuze kulingiswe isimo sezulu esinomswakama eChongqing, umhloli wesifutho sikasawoti ushintshwe ngokukhethekile futhi waklanywa25. Njengoba kuboniswe kuMfanekiso 1, imishini yokuhlola inezinhlelo ezimbili: uhlelo lwesifutho sikasawoti kanye nohlelo lokukhanyisa. Uhlelo lwesifutho sikasawoti luwumsebenzi oyinhloko wemishini yokuhlola, equkethe ingxenye yokulawula, ingxenye yesifutho kanye nengxenye yokungenisa. Umsebenzi wengxenye yesifutho ukupompa inkungu kasawoti egumbini lokuhlola nge-compressor yomoya. Ingxenye yesifutho yakhiwe yizinto zokulinganisa izinga lokushisa, ezwa izinga lokushisa ekamelweni lokuhlola. Ingxenye yokulawula yakhiwe yi-microcomputer, exhumanisa ingxenye yesifutho kanye nengxenye yokungenisa ukulawula yonke inqubo yokuhlola. Uhlelo lokukhanyisa lufakwe ekamelweni lokuhlola lesifutho sikasawoti ukuze lilingise ukukhanya kwelanga. Uhlelo lokukhanyisa luqukethe izibani ze-infrared kanye nesilawuli sesikhathi. Ngesikhathi esifanayo, kufakwa inzwa yokushisa ekamelweni lokuhlola lesifutho sikasawoti ukuze kuqashwe izinga lokushisa elizungeze isampula ngesikhathi sangempela.
Amasampula okugqwala kokucindezeleka ngaphansi komthwalo ongaguquki acutshungulwa ngokuhambisana ne-NACETM0177-2005 (Ukuhlolwa Kwelabhorethri Kokuqhekeka Kokucindezeleka Kwe-Sulfide kanye Nokumelana Nokugqwala Kokucindezeleka Kwezinsimbi Endaweni Ye-H2S). Amasampula okugqwala kokucindezeleka aqale ahlanzwa nge-acetone kanye nokuhlanza ngomshini we-ultrasonic ukuze kususwe izinsalela zamafutha, bese kucwiliswa ngotshwala bese komiswa kuhhavini. Bese kufakwa amasampula ahlanzekile ekamelweni lokuhlola ledivayisi yokuhlola i-salt spray ukuze kulingiswe isimo sokugqwala endaweni yesimo sezulu esinomswakama saseChongqing. Ngokusho kwe-NACETM0177-2005 ejwayelekile kanye ne-salt spray test standard GB/T 10,125-2012, isikhathi sokuhlola ukugqwala kokucindezeleka komthwalo ongaguquki kulolu cwaningo sinqunywa ngokulinganayo ukuthi singamahora angu-168. Ukuhlolwa kwe-tensile kwenziwa kumasampula okugqwala ngaphansi kwezimo ezahlukene zokugqwala emshinini wokuhlola we-MTS-810 jikelele, futhi izakhiwo zawo zomshini kanye nesimo sokugqwala kokuqhekeka kwahlaziywa.
Isithombe 1 sibonisa i-macro- kanye ne-micro-morphology yokugqwala kobuso bezibonelo zokugqwala kwe-bolt stress enamandla aphezulu ngaphansi kwezimo ezahlukene zokugqwala. 2 kanye no-3 ngokulandelana.
Ukwakheka kwe-macroscopic kwamasampula okugqwala kokucindezeleka kwama-bolts anamandla aphezulu e-20MnTiB ngaphansi kwezimo ezahlukene zokugqwala ezilingisiwe: (a) akukho ukugqwala; (b) isikhathi esisodwa; (c) 20 ×; (d) 200 ×; (e) pH3.5; (f) pH 7.5; (g) 50°C.
I-Micromorphology yemikhiqizo yokugqwala yama-bolts anamandla aphezulu e-20MnTiB ezindaweni ezahlukene zokugqwala ezilingisiwe (100×): (a) isikhathi esi-1; (b) 20 ×; (c) 200 ×; (d) pH3.5; (e) pH7 .5; (f) 50°C.
Kungabonakala ku-Fig. 2a ukuthi ubuso besampula yebholithi enamandla aphezulu engagqwali bubonisa ukukhanya kwensimbi okukhanyayo ngaphandle kokugqwala okusobala. Kodwa-ke, ngaphansi kwesimo sesisombululo sokuqala sokugqwala esilingisiwe (Fig. 2b), ubuso besampula babumbozwe kancane ngemikhiqizo yokugqwala enombala onsundu nobomvu onsundu, kanti ezinye izindawo zobuso zazisabonisa ukukhanya kwensimbi okusobala, okubonisa ukuthi ezinye izindawo zobuso besampula kuphela ezazigqwalile kancane, futhi isisombululo sokugqwala esilingisiwe asizange sibe nomthelela ebusweni besampula. Izakhiwo zezinto azinawo umphumela omkhulu. Kodwa-ke, ngaphansi kwesimo sokuhlushwa kwesisombululo sokugqwala esilingisiwe esingu-20 × (Isithombe 2c), ubuso besampula yebholithi enamandla aphezulu bumbozwe ngokuphelele inani elikhulu lemikhiqizo yokugqwala enombala onsundu kanye nenani elincane lokugqwala okunsundu-obomvu. Umkhiqizo, akukho ukukhanya kwensimbi okusobala okutholiwe, futhi kwakukhona inani elincane lomkhiqizo wokugqwala onsundu-omnyama eduze kobuso be-substrate. Futhi ngaphansi kwesimo sokuhlushwa kwesisombululo sokugqwala esilingisiwe esingu-200 × (Isithombe 2d), ubuso besampula bumbozwe ngokuphelele yimikhiqizo yokugqwala ensundu, futhi imikhiqizo yokugqwala ensundu-omnyama ivela kwezinye izindawo.
Njengoba i-pH yehla yaya ku-3.5 (Isithombe 2e), imikhiqizo yokugqwala enombala onsundu yayiyiyona ebaluleke kakhulu ebusweni bamasampula, futhi eminye yemikhiqizo yokugqwala yayikhishwe amabala.
Isithombe 2g sibonisa ukuthi njengoba izinga lokushisa likhuphuka lifike ku-50 °C, okuqukethwe kwemikhiqizo yokugqwala ensundu-bomvu ebusweni besampula kwehla kakhulu, kuyilapho imikhiqizo yokugqwala ensundu ekhanyayo imboza ubuso besampula endaweni enkulu. Ingqimba yomkhiqizo wokugqwala ikhululekile, futhi eminye imikhiqizo ensundu-mnyama iyahlutshulwa.
Njengoba kuboniswe kuMfanekiso 3, ngaphansi kwezimo ezahlukene zokugqwala, imikhiqizo yokugqwala ebusweni bezibonelo zokugqwala ze-20MnTiB ezinamandla aphezulu zokucindezeleka kwebholithi ihlukaniswe ngokusobala, futhi ubukhulu besendlalelo sokugqwala buyanda ngokwanda kokuhlushwa kwesisombululo sokugqwala esilingisiwe. Ngaphansi kwesimo sesisombululo sokugqwala esilingisiwe sokuqala (Umfanekiso 3a), imikhiqizo yokugqwala ebusweni besampula ingahlukaniswa ibe yizingqimba ezimbili: isendlalelo sangaphandle semikhiqizo yokugqwala sisatshalaliswa ngokulinganayo, kodwa kuvela inani elikhulu lokuqhekeka; isendlalelo sangaphakathi siyiqoqo elikhululekile lemikhiqizo yokugqwala. Ngaphansi kwesimo sokuhlushwa kwesisombululo sokugqwala esilingisiwe esingu-20× sokuqala (Umfanekiso 3b), isendlalelo sokugqwala ebusweni besampula singahlukaniswa sibe yizingqimba ezintathu: isendlalelo sangaphandle kakhulu yimikhiqizo yokugqwala yeqembu ehlakazekile, ekhululekile futhi embozwe yizimbobo, futhi engenawo umsebenzi omuhle wokuvikela; Isendlalelo esiphakathi siyisendlalelo somkhiqizo wokugqwala esifanayo, kodwa kunezingqimba ezisobala, futhi ama-ion okugqwala angadlula ezingqimbeni futhi agugule isisekelo; ungqimba lwangaphakathi luyingqimba lomkhiqizo wokugqwala oqinile ongenazo izimfa ezisobala, olunomphumela omuhle wokuvikela ku-substrate. Ngaphansi kwesimo sokuhlushwa kwesisombululo sokugqwala esilingisiwe esingu-200× (Isithombe 3c), ungqimba lokugqwala ebusweni besampula lungahlukaniswa lube yizingqimba ezintathu: ungqimba lwangaphandle luyingqimba lomkhiqizo wokugqwala oluncane nolufanayo; ungqimba oluphakathi luyimfa ikakhulukazi efana ne-petal kanye ne-flake. Ungqimba lwangaphakathi luyingqimba lomkhiqizo wokugqwala oqinile ongenazo izimfa nezimbobo ezisobala, olunomphumela omuhle wokuvikela ku-substrate.
Kungabonakala ku-Fig. 3d ukuthi endaweni yokugqwala okulingisiwe ye-pH 3.5, kunenani elikhulu lemikhiqizo yokugqwala efana ne-flocculent noma efana nenaliti ebusweni besampula ye-bolt enamandla aphezulu ye-20MnTiB. Kucatshangwa ukuthi le mikhiqizo yokugqwala ikakhulukazi i-γ-FeOOH kanye nenani elincane le-α-FeOOH elihlanganisiwe26, futhi ungqimba lokugqwala lunemifantu esobala.
Kungabonakala ku-Fig. 3f ukuthi lapho izinga lokushisa lenyuka laya ku-50 °C, akukho ungqimba lokugqwala olucacile olutholakala esakhiweni sengqimba yokugqwala, okubonisa ukuthi kwakukhona izikhala phakathi kwezingqimba zokugqwala ku-50 °C, okwenza i-substrate ingambozwa ngokuphelele yimikhiqizo yokugqwala. Ihlinzeka ngesivikelo ekuthambekeleni kokugqwala kwe-substrate okwandisiwe.
Izakhiwo zomshini zamabholidi anamandla aphezulu ngaphansi kokugqwala kokucindezeleka komthwalo okuqhubekayo ezindaweni ezahlukene zokugqwala ziboniswe kuThebula 2:
Kungabonakala kuThebula 2 ukuthi izakhiwo zemishini zamasampula e-bolt aphezulu e-20MnTiB zisahlangabezana nezidingo ezijwayelekile ngemuva komjikelezo owomile omanzi osheshise ukuhlolwa kokugqwala ezindaweni ezahlukene zokugqwala ezilingisiwe, kodwa kukhona umonakalo othile uma kuqhathaniswa nalezo ezingagqwali. Isampula. Ekugxilweni kwesisombululo sokuqala sokugqwala esilingisiwe, izakhiwo zemishini zesampula azishintshanga kakhulu, kodwa ekugxilweni okungu-20× noma okungu-200× kwesisombululo esilingisiwe, ukunwebeka kwesampula kwehle kakhulu. Izakhiwo zemishini ziyafana ekugxilweni kwezixazululo zokugqwala zokuqala ezingama-20 × no-200 ×. Lapho inani le-pH lesisombululo sokugqwala esilingisiwe lehla laya ku-3.5, amandla okudonswa kanye nokwandiswa kwamasampula kwehle kakhulu. Lapho izinga lokushisa lenyuka laya ku-50°C, amandla okudonswa kanye nokwandiswa kwehla kakhulu, futhi izinga lokuncishiswa kwendawo liseduze kakhulu nenani elijwayelekile.
Izinhlobo zokuphuka kwezinhlobo zokubola kwe-20MnTiB high-strength bolt stress corrosion specimens ngaphansi kwezimo ezahlukene zokubola ziboniswe kuMfanekiso 4, okuyizinhlobo ezinkulu zokuphuka kwe-fracture, indawo ye-fiber enkabeni yokuphuka, i-micro-morphological lip ye-shear interface, kanye nobuso besampula.
Ukwakheka kokuqhekeka okukhulu nokuncane kakhulu kwamasampula e-bolt anamandla aphezulu e-20MnTiB ezindaweni ezahlukene zokugqwala ezilingisiwe (500×): (a) akukho ukugqwala; (b) isikhathi esisodwa; (c) 20 ×; (d) 200 ×; (e) pH3.5; (f) pH7.5; (g) 50°C.
Kungabonakala kuFig. 4 ukuthi ukuphuka kwesampula yokugqwala ye-20MnTiB enamandla amakhulu ngaphansi kwezindawo ezahlukene zokugqwala ezilingisiwe kuveza ukuphuka okuvamile kwe-cup-cone. Uma kuqhathaniswa nesampula engagqwali (Fig. 4a), indawo ephakathi nendawo ye-fiber area crack incane kakhulu. , indawo ye-shear lip inkulu. Lokhu kukhombisa ukuthi izakhiwo zemishini zezinto zonakaliswe kakhulu ngemva kokugqwala. Ngokwanda kokuhlushwa kwesisombululo sokugqwala esilingisiwe, imigodi endaweni ye-fiber maphakathi nokuqhekeka yanda, futhi kwavela izikhala zokudabuka ezisobala. Lapho ukuhlushwa kwanda izikhathi ezingama-20 kunesixazululo sokugqwala esilingisiwe sokuqala, imigodi yokugqwala esobala yavela endaweni ephakathi komphetho we-shear lip kanye nobuso besampula, futhi kwakukhona imikhiqizo eminingi yokugqwala ebusweni.
Kuvela kuMfanekiso 3d ukuthi kunemifantu esobala kungqimba lokugqwala ebusweni besampula, okungenawo umphumela omuhle wokuvikela ku-matrix. Esixazululweni sokugqwala esilingisiwe se-pH 3.5 (Isithombe 4e), ubuso besampula bugqwalile kakhulu, futhi indawo ephakathi yefayibha incane ngokusobala. , Kunenqwaba yemithungo yokudabuka engajwayelekile phakathi nendawo yefayibha. Ngokukhuphuka kwenani le-pH lesisombululo sokugqwala esilingisiwe, indawo yokudabuka endaweni yefayibha phakathi nendawo yokuqhekeka iyancipha, umgodi uyancipha kancane kancane, futhi ukujula komgodi nakho kwehla kancane kancane.
Lapho izinga lokushisa lenyuka laya ku-50 °C (Isithombe 4g), indawo yokusika izindebe lapho kwaphuka khona isampula yayiyinkulu kunazo zonke, imigodi endaweni ephakathi kwefayibha yanda kakhulu, kanti nokujula komgodi kwanda, kanti nokuxhumana phakathi komphetho wokusika izindebe kanye nobuso besampula kwanda. Imikhiqizo yokugqwala kanye nemigodi kwanda, okwaqinisekisa ukuthambekela kokujula kokugqwala kwe-substrate okuboniswe ku-Isithombe 3f.
Inani le-pH lesisombululo sokugqwala lizobangela umonakalo othile ezimpahleni zemishini zama-bolts anamandla aphezulu angu-20MnTiB, kodwa umphumela awubalulekile. Esixazululweni sokugqwala se-pH 3.5, inani elikhulu lemikhiqizo yokugqwala efana ne-flocculent noma efana nenaliti isatshalaliswa ebusweni besampula, futhi ungqimba lokugqwala lunemifantu esobala, engakwazi ukwakha isivikelo esihle se-substrate. Futhi kunemigodi yokugqwala esobala kanye nenani elikhulu lemikhiqizo yokugqwala ku-morphology encane yokuqhekeka kwesampula. Lokhu kukhombisa ukuthi ikhono lesampula lokumelana nokuguqulwa ngamandla angaphandle lincishisiwe kakhulu endaweni ene-acidic, futhi izinga lokuthambekela kokugqwala kokucindezeleka kwezinto likhushulwa kakhulu.
Isixazululo sokuqala sokugqwala esilingisiwe sasingenawo umthelela omkhulu ezimpahleni zemishini zamasampula ebholiti anamandla aphezulu, kodwa njengoba ukuhlushwa kwesisombululo sokugqwala esilingisiwe kwanda kwaze kwaba izikhathi ezingu-20 kunesixazululo sokuqala sokugqwala esilingisiwe, izakhiwo zemishini zamasampula zonakala kakhulu, futhi kwaba nokugqwala okusobala esakhiweni esincane sokuqhekeka, imigodi, imifantu yesibili kanye nemikhiqizo eminingi yokugqwala. Lapho ukuhlushwa kwesisombululo sokugqwala esilingisiwe kwanda kusuka ezikhathini ezingu-20 kuya kwezingu-200 zokuhlushwa kwesisombululo sokuqala sokugqwala esilingisiwe, umphumela wokuhlushwa kwesisombululo sokugqwala ezimpahleni zemishini zezinto wancipha.
Uma izinga lokushisa lokugqwala elilingisiwe lingu-25℃, amandla okukhiqiza kanye namandla okudonsa amasampula e-bolt aphezulu e-20MnTiB awashintshi kakhulu uma kuqhathaniswa namasampula angagqwali. Kodwa-ke, ngaphansi kwezinga lokushisa lokushisa lokugqwala elingu-50 °C, amandla okudonsa kanye nokwelulwa kwesampula kwehle kakhulu, izinga lokuncipha kwesigaba laliseduze nenani elijwayelekile, udebe lokugunda oluqhekekile lwalulukhulu kunawo wonke, futhi kwakukhona ama-dimples endaweni ephakathi yefayibha. Kwanda kakhulu, ukujula komgodi kwanda, imikhiqizo yokugqwala kanye nemigodi yokugqwala kwanda. Lokhu kubonisa ukuthi indawo yokugqwala ehambisanayo yokushisa inethonya elikhulu ezimpahleni zemishini zama-bolt anamandla aphezulu, okungabonakali ekushiseni kwegumbi, kodwa okubaluleke kakhulu lapho izinga lokushisa lifinyelela ku-50 °C.
Ngemva kokuhlolwa kokugqwala okusheshisiwe kwangaphakathi okulingisa imvelo yasemkhathini eChongqing, amandla okudonseka, amandla okukhiqiza, ukunwebeka kanye nezinye izinhlaka zamabholidi anamandla aphezulu e-20MnTiB ancishisiwe, futhi kwenzeka umonakalo osobala wokucindezeleka. Njengoba izinto zingaphansi kokucindezeleka, kuzoba nesenzakalo esibalulekile sokusheshisa ukugqwala kwendawo. Futhi ngenxa yomphumela ohlangene wokugxila kokucindezeleka kanye nemigodi yokugqwala, kulula ukubangela umonakalo osobala wepulasitiki kumabholidi anamandla aphezulu, ukunciphisa ikhono lokumelana nokuguquguquka kwamandla angaphandle, nokwandisa ukuthambekela kokugqwala kokucindezeleka.
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