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Intsimbi ye-20MnTiB yeyona nto isetyenziswa kakhulu ibholithi ephezulu yokuqina kwebhulorho yesakhiwo sentsimbi kwilizwe lam, kwaye ukusebenza kwayo kubaluleke kakhulu ekusebenzeni okukhuselekileyo kweebhulorho.Ngokusekwe kuphando lwemekobume yomoya eChongqing, olu phononongo lwenze isisombululo somhlwa esilinganisa imozulu efumileyo yeChongqing, kwaye iqhube uvavanyo lwemozulu efumileyo ye-Chongqing ye-chongqing yemozulu. iziphumo zeqondo lokushisa, ixabiso le-pH kunye nokugxininiswa kwesisombululo se-corrosion kwi-corrosion yokuziphatha koxinzelelo lwe-20MnTiB i-bolts high-power bolts yafundwa.
I-20MnTiB yensimbi iyona nto isetyenziswa kakhulu i-bolt high-sight-bolt material for steel structure bridges kwilizwe lam, kwaye ukusebenza kwayo kubaluleke kakhulu ekusebenzeni okukhuselekileyo kweebhulorho.Li et al.I-1 ivavanye iipropathi zentsimbi ye-20MnTiB eqhele ukusetyenziswa kwibakala le-10.9 iibholiti zokuqina okuphezulu kwinqanaba lobushushu obuphezulu be-20 ~ 700 ℃, kwaye yafumana i-curve yoxinzelelo-strain, amandla esivuno, amandla okuqina, imodyuli yoMncinci, kunye nobude.kunye ne-coefficient yokwandisa.Zhang et al.2, Hu et al.I-3, njl., ngovavanyo lokubunjwa kweekhemikhali, uvavanyo lwepropathi yomatshini, uvavanyo lwe-microstructure, uhlalutyo lwe-macroscopic kunye ne-microscopic ye-thread surface, kunye neziphumo zibonisa ukuba esona sizathu sibalulekileyo sokuqhekeka kweebholiti zamandla aphezulu zihambelana neziphene zentambo, kunye nokuvela kweziphene zentambo Ukugxininiswa okukhulu koxinzelelo, ukugxininiswa kwe-crack tip kunye ne-open-air corrosion corrosion.
Iibholiti eziphezulu zentsimbi yeebhulorho zentsimbi zidla ngokusetyenziswa ixesha elide kwindawo efumileyo.Izinto ezifana nokufuma okuphezulu, ubushushu obuphezulu, kunye nentlenga kunye nokufunxwa kwezinto eziyingozi kwimo engqongileyo kunokubangela ukuba kube lula ukubola kwezakhiwo zentsimbi.I-Corrosion inokubangela ilahleko ephezulu yamandla e-bolt, okukhokelela ekuqhekekeni kunye nokuqhekeka okuninzi, kwaye ezi zinto ziya kukhula kwaye ziqhubele phambili ukuqhekeka. -i-bolts zamandla kwaye zibangele ukuba ziphuke.Okwangoku, kukho izifundo ezininzi malunga nefuthe le-corrosion yendalo kwintsebenzo yoxinzelelo lwe-corrosion yezinto eziphathekayo.I-Catar et al4 iphande ngokuziphatha koxinzelelo lwe-corrosion ye-magnesium alloys kunye nemixholo eyahlukeneyo ye-aluminium kwi-acidic, i-alkaline kunye neendawo ezingathathi hlangothi ngokucotha kovavanyo lwesantya soxinzelelo (SSRT.5) I-Abdel corrosion yokuziphatha kwe-stressing ye-stressing i-AlNicorosion ye-AlNicorsion ye-Abdel 5 i-AlNicorsion ye-Stressing I-AlNicorsion ye-Abdel. I-3.5% isisombululo se-NaCl phambi koxinzelelo oluhlukeneyo lwee-ion ze-sulfide. U-Aghion et al.6 uvavanye ukusebenza kwe-corrosion ye-die-cast magnesium alloy MRI230D kwi-3.5% isisombululo se-NaCl ngovavanyo lokucwiliswa, uvavanyo lokutshiza ityuwa, uhlalutyo lwe-polarization olunamandla kunye ne-SSRT.Zhangnsite yokuziphatha kwe-stressCrrtic ye-stressic et al-9. ubuchule bokuvavanya, kwaye ifumene isiphumo se-ion chloride kwi-static corrosion behavior ye-martensitic steel at room temperature.Chen et al.8 iphande ngokuziphatha koxinzelelo lwe-corrosion kunye ne-crack mechanism ye-X70 yentsimbi kwisisombululo esifanisiweyo sodaka oluqulethe i-SRB kumaqondo obushushu ahlukeneyo yi-SSRT.Liu et al.9 isebenzise i-SSRT kwizinga lobushushu le-000 yoxinzelelo lwe-stressertrain ye-treasurestrain ye-stress0 amanzi I-1Ni14Mn5Mo2N i-austenitic stainless steel stainless.Iziphumo zibonisa ukuba ubushushu kuluhlu lwe-35 ~ 65 ℃ alunampembelelo ebalulekileyo ekuziphatheni koxinzelelo lwe-corrosion yensimbi engenasici.Lu et al.I-10 ivavanye ukulibaziseka kokuphuka kweesampulu ezinamabakala ahlukeneyo okuqina kwamandla ngomthwalo ofileyo ukulibaziseka kovavanyo lwe-fracture kunye ne-SSRT.Kucetyiswa ukuba amandla okuqina kwe-20MnTiB yentsimbi kunye ne-35VB yentsimbi ephezulu yokuqina kufuneka ilawulwe kwi-1040-1190MPa. okusingqongileyo, ngelixa indawo yokusetyenziswa yokwenene yeebholiti eziphezulu zokuqina ziyinkimbinkimbi kwaye inezinto ezininzi ezichaphazelayo, ezifana nexabiso le-pH ye-bolt.Ananya et al.I-11 ifunde umphumo weeparameters zokusingqongileyo kunye nezinto eziphathekayo kwindawo ephazamisayo kwi-corrosion kunye noxinzelelo lwe-corrosion cracking ye-duplex stainless steels.Sunada et al.I-12 iqhube iimvavanyo zokuqhekeka kweqondo lokushisa kwegumbi kwi-SUS304 intsimbi kwizisombululo ezinamanzi eziqulathe i-H2SO4 (0-5.5 kmol/m-3) kunye ne-NaCl (0-4.5 kmol/m-3) s uxinzelelo kunye nexesha lokubola kwi-corrosion susceptibility yoxinzelelo lwe-A516 isitya soxinzelelo lwentsimbi. Ukusebenzisa isisombululo se-NS4 njengesisombululo sokulinganisa amanzi aphantsi komhlaba, u-Ibrahim et al.I-14 iphande isiphumo seeparamitha zokusingqongileyo ezifana ne-bicarbonate ion (HCO) yoxinaniso, i-pH kunye nobushushu kwi-stress corrosion cracking ye-API-X100 yentsimbi yombhobho emva kokuxobula i-coating.Shan et al.I-15 ifunde umthetho wenguqu yoxinzelelo lwe-corrosion cracking susceptibility ye-austenitic stainless steel 00Cr18Ni10 kunye nobushushu phantsi kweemeko ezahlukeneyo zobushushu (30 ~ 250 ℃) phantsi kwemeko yamanzi amnyama aphakathi kwisityalo esifanisiweyo samalahle ukuya kwi-hydrogen nge-SSRT. kunye ne-SSRT.Zhao17 ifunde imiphumo ye-pH, i-SO42-, i-Cl-1 kukuziphatha koxinzelelo lwe-GH4080A i-alloy nge-SSRT. impembelelo ye-corrosion yendalo kwi-20MnTiB yentsimbi ye-bolts high-power bolts.
Ukuze ufumane izizathu zokungaphumeleli kweebholiti eziphezulu ezisetyenziswa kwiibhulorho, umbhali uye wenza uthotho lwezifundo.Iisampulu zebholithi zamandla aphezulu zakhethwa, kwaye izizathu zokungaphumeleli kwezi sampuli zaxoxwa ngemibono yokwakheka kweekhemikhali, i-morphology ye-fracture microscopic, i-metallographic structure kunye ne-mechanical properties analysis19, i-20 phenyng ye-angqing yophando kwiminyaka yakutshanje kwi-ngqingxing ye-angqing. Isikimu esilinganisa imozulu efumileyo yaseChongqing siyilwe. Uvavanyo lokutya koxinzelelo, imifuniselo ye-electrochemical corrosion kunye nokudinwa kokudinwa kweebholiti zamandla aphezulu eChongqing efanisiweyo yemozulu efumileyo yenziwa. Kolu phononongo, iziphumo zobushushu, ixabiso le-pH kunye nokuxinana kwesisombululo esifanisiweyo somhlwa kuxinzelelo lwe-corrosion yokuziphatha, utyalo-mali loxinzelelo lwe-corrosion ye-20M yepropathi egrunjiweyo ye-20M yepropathi yotyalo-mali. uhlalutyo olukhulu kunye ne-microscopic, kunye neemveliso zokubola komphezulu.
IChongqing ikumzantsi-ntshona weChina, iindawo eziphezulu zoMlambo iYangtze, kwaye inemozulu efumileyo yemonsoon.Iqondo lobushushu lonyaka yi-16-18°C, umyinge wonyaka wokufuma kwesalamane ubukhulu becala yi-70-80%, iiyure zonyaka zokukhanya kwelanga ziiyure eziyi-1000-1400, kunye nepesenteji yelanga-35 kuphela.
Ngokweengxelo ezinxulumene nokukhanya kwelanga kunye nobushushu be-ambient e-Chongqing ukusuka ngo-2015 ukuya ku-2018, i-avareji yobushushu bemihla ngemihla e-Chongqing isezantsi nge-17°C kwaye iphezulu ukuya kuma-23°C.Elona qondo lobushushu liphezulu kumzimba webhulorho ye-Chaotianmen Bridge e-Chongqing linokufikelela kwi-50 ° C °C21,22. Ngoko ke, amanqanaba obushushu ovavanyo lwe-corrosion yoxinzelelo abekwe kwi-25 ° C kunye ne-50 ° C.
Ixabiso le-pH yesisombululo esilinganisiweyo somhlwa sichaza ngokuthe ngqo ubungakanani be-H +, kodwa oko akuthethi ukuba iphantsi ixabiso le-pH, ukuhlwa kulula kwenzeka.Impembelelo ye-pH kwiziphumo iya kuhluka kwizinto ezahlukeneyo kunye nezisombululo. Ukuze ufunde kakuhle impembelelo yesisombululo esilinganisiweyo somhlwa kuxinzelelo lwentsebenzo ye-corrosion ye-high-power bolts, i-pH ye-5 corrosion kunye ne-5 yovavanyo. ngokudibanisa nophando loncwadi23 kunye noluhlu lwe-pH lwamanzi emvula ngonyaka eChongqing.2010 ukuya ku-2018.
Ukuphakama koxinzelelo lwesisombululo esifanisiweyo somhlwa, kokukhona umxholo we-ion kwisisombululo somhlwa esifanisiweyo, kunye nempembelelo enkulu kwizinto eziphathekayo. Ukuze kufundwe isiphumo sokuxinana kwesisombululo esifanisiweyo somhlwa kwi-corrosion yoxinzelelo lweebholiti zamandla aphezulu, ilabhoretri eyenziwe yakhawulezisa uvavanyo lokurhweba lwaye lwenziwa, kunye nesisombululo esifanisiweyo se-corrosion samiselwa, kunye nesisombululo esifanisiweyo. i-rosion solution concentration (1 ×), i-20 × i-original simulated corrosion solution concentration (20 ×) kunye ne-200 × i-original simulated corrosion solution concentration (200 ×).
Imo engqongileyo kunye nobushushu be-25 ℃, ixabiso le-pH le-5.5, kunye nokugxininiswa kwesisombululo se-corrosion yasekuqaleni esondeleyo kwiimeko ezichanekileyo zokusetyenziswa kweebholiti zamandla aphezulu kwiibhulorho.Nangona kunjalo, ukuze kukhawuleziswe inkqubo yovavanyo lwe-corrosion, iimeko zovavanyo kunye nobushushu be-25 °C, i-pH ye-5.20 ye-corrosion kunye ne-corrosion ye-5.5 × i-corrosion ye-concentration ye-original iseti. imiphumo yeqondo lokushisa, i-concentration okanye ixabiso le-pH yesisombululo esifanisiweyo sokutshatyalaliswa kwintsebenzo yoxinzelelo lwe-corrosion ye-bolts ephezulu yaphandwa ngokulandelanayo, ezinye izinto zahlala zingatshintshi, ezisetyenziswe njengenqanaba lokulinga leqela lokulawula ireferensi.
Ngokwengxelo yomgangatho wemo engqongileyo ka-2010-2018 ekhutshwe yiChongqing Municipal Bureau of Ecology and Environment, kwaye ibhekisa kumacandelo emvula exelwe kwiZhang24 kunye nolunye uncwadi oluxelwe eChongqing, isisombululo somhlwa esisekwe ekonyuseni koxinzelelo lwe-SO42- sayilwa. Ukwakheka kwengqimba eyi-1 yengqimba yengqimba ye-2 yengqimba yengqimba ye-2 yengqimba yengqimba ye-2 yengqimba yengqimba yengqimba ye-2. isisombululo serosion siboniswe kwiThebhile 1:
Isisombululo se-corrosion esilinganisiweyo silungiswa nge-chemical ion concentration balance method usebenzisa i-reagents analytical kunye ne-distilled water.Ixabiso le-pH yesisombululo esilinganisiweyo somhlwa salungiswa nge-pH meter echanekileyo, isisombululo se-nitric acid kunye nesisombululo se-sodium hydroxide.
Ukuze ukulinganisa isimo sezulu esinomswakama eChongqing, umhloli wetyuwa wetyuwa uguqulwe ngokukodwa kwaye uyilwe 25. Njengoko kuboniswe kuMzobo 1, izixhobo zokulinga zineenkqubo ezimbini: inkqubo yokutshiza ityuwa kunye nenkqubo yokukhanyisa. Inkqubo yokutshiza ityuwa ngumsebenzi oyintloko wezixhobo zokulinga, ezibandakanya inxalenye yokulawula, inxalenye yokutshiza kunye nenxalenye ye-induction. yezinto zokulinganisa ubushushu, eziqonda ubushushu kwigumbi lovavanyo.Icandelo lolawulo liqulunqwe yi-microcomputer, edibanisa inxalenye yokutshiza kunye nenxalenye yokungeniswa ukulawula yonke inkqubo yovavanyo.Inkqubo yokukhanyisa ifakwe kwigumbi lokuvavanya ityuwa yokutshiza ukulinganisa ukukhanya kwelanga.Inkqubo yokukhanyisa iqulethe izibane ze-infrared kunye nomlawuli wexesha.Ngexesha elifanayo, ukubeka iliso kwisampulu yokuvavanya kwiqondo lokushisa lokwenene kwindawo yokuvavanya ityuwa.
Iisampuli ze-Stress corrosion phantsi komthwalo oqhubekayo zicutshungulwa ngokuhambelana ne-NACE TM0177-2005 (Uvavanyo lweLabhoratri ye-Sulfide Stress Cracking kunye ne-Stress Corrosion Cracking Resistance of Metals kwi-H2S Environmental) .Iisampuli ze-corrosion ze-Stress zihlanjululwe kuqala nge-acetone kunye ne-ultrasonic mechanical cleaned kunye ne-ultrasonic mechanical cleans kunye ne-alcohol ecocekileyo ibeka i-alcohol ecocekileyo kunye ne-oyile ecocekileyo ecocekileyo kunye ne-alcohol de i-hydrated ecocekileyo. igumbi lokuvavanya isixhobo sovavanyo lokutshiza ityuwa ukulinganisa imeko ye-corrosion kwimeko yemozulu efumileyo ye-Chongqing.Ngokutsho kwe-NACETM0177-2005 eqhelekileyo kunye nomgangatho wokuvavanya ityuwa yokutshiza umgangatho we-GB/T 10,125-2012, ixesha lovavanyo loxinzelelo lwe-corrosion rhoqo kolu phononongo lumiselwe ngokufanayo ukuba lube yi-168 isampula ye-corrosion kwi-corrosion test phantsi kwe-corrosion ye-10. I-TS-810 umatshini wokuvavanya i-universal tensile, kunye neempawu zabo zoomatshini kunye ne-fracture corrosion morphology yahlalutywa.
Umzobo we-1 ubonisa i-macro- kunye ne-micro-morphology ye-surface corrosion ye-high-strength-bolt stress stress corrosion specimens phantsi kweemeko ezahlukeneyo zokubola.2 kunye ne-3 ngokulandelanayo.
I-Macroscopic morphology ye-stress corrosion specimens ze-20MnTiB iibholiti zamandla aphezulu phantsi kweemeko-bume zomhlwa ezifanisiweyo ezahlukeneyo: (a) akukho mhlwa;(b) ixesha eli-1;(c) 20 ×;(d) 200 ×;(e) pH3.5;(f) pH 7.5;(g) 50°C.
I-Micromorphology yeemveliso ze-corrosion ye-20MnTiB i-bolts yamandla aphezulu kwiindawo ezahlukeneyo zokubola okufanisiweyo (100 ×): (a) ixesha le-1;(b) 20 ×;(c) 200 ×;(d) pH3.5;(e) pH7 .5;(f) 50°C.
Inokubonwa ukusuka Fig. 2a ukuba umphezulu uncorroded high-amandla bolt umfuziselo ubonisa ukukhazimla metallic eqaqambileyo ngaphandle corrosion.Noko ke, phantsi kwemeko yesisombululo yoqobo eyenziwe umhlwa (Fig. 2b), umphezulu isampulu ngokuyinxenye egutyungelwe tan kunye nomdaka-red-red imveliso umhlwa, kwaye ezinye iindawo ezicacileyo umphezulu imveliso yentsimbi kuphela, kwaye ezinye iindawo ezicacileyo umphezulu luster luster, kwaye ezinye iindawo ezicacileyo zomphezulu we-metal corrosion, kwaye ezinye iindawo ezicacileyo zomphezulu we-metal corrosion, kwaye ezinye iindawo ezicacileyo zomphezulu we-metal corrosion, kwaye ezinye iindawo ezicacileyo zomphezulu we-metal corrosion. , kunye nesisombululo se-corrosion esifanisiweyo sasingenayo impembelelo kumphezulu wesampuli.Iimpawu zezinto eziphathekayo zinempembelelo encinane.Nangona kunjalo, phantsi kwemeko ye-20 × yoqobo yoxinaniso lwesisombululo somhlwa (umzobo 2c), umphezulu womfanekiso webholithi wamandla aphezulu ugutyungelwe ngokupheleleyo sisixa esikhulu semveliso ye-tan corrosion kunye nesixa esincinci se-brown-red corrosion.product, akukho luster ecacileyo yesinyithi yafunyanwa, kwaye kukho imveliso emdaka phantsi komgangatho omncinci womgangatho omdaka. I-200 × yoqobo yoxinaniso lwesisombululo se-corrosion esifanisiweyo (Umfanekiso we-2d), umphezulu wesampuli ugutyungelwe ngokupheleleyo yimveliso ye-corrosion emdaka, kunye neemveliso ze-brown-black corrosion zibonakala kwezinye iindawo.
Njengoko i-pH yehla ukuya kwi-3.5 (umzobo 2e), iimveliso ze-corrosion ezinemibala ye-tan yayiyeyona nto iphezulu phezu kweesampuli, kwaye ezinye zeemveliso ze-corrosion ziye zakhutshwa.
Umfanekiso we-2g ubonisa ukuba njengoko ubushushu bukhula ukuya kuma-50 ° C, umxholo weemveliso ezimdaka-ebomvu kumphezulu wesampuli uyancipha ngokukhawuleza, ngelixa iimveliso ze-corrosion ezikhanyayo zigubungela umphezulu wesampuli kwindawo enkulu.Imveliso yemveliso ye-corrosion ikhululekile, kwaye ezinye iimveliso ezimdaka-ezimnyama zixotshiwe.
Njengoko kubonisiwe kwiSazobe sesi-3, phantsi kweemeko ezahlukeneyo zomhlwa, iimveliso zomhlwa kumphezulu we-20MnTiB amandla aphezulu e-bolt stress i-corrosion specimens ngokucacileyo zihlanjululwe, kwaye ubukhulu be-corrosion layer inyuka ngokunyuka koxinzelelo lwesisombululo esifanisiweyo. zibe ngamacandelo amabini: uluhlu lwangaphandle lweemveliso ze-corrosion lusasazwa ngokulinganayo, kodwa inani elikhulu lokuqhekeka livela;umaleko wangaphakathi yiqela elikhululekileyo leemveliso zomhlwa.Ngaphantsi kwemeko ye-20 × yoqobo yoxinaniso lwesisombululo se-corrosion (Umfanekiso we-3b), umaleko we-corrosion kumphezulu wesampulu unokwahlulwa ube ngamacandelo amathathu: umaleko ongaphandle uhlakazekile ngokuyintloko iimveliso ze-corrosion yeqela, ezikhululekileyo nezikhuselayo, kwaye azinamsebenzi olungileyo;Uluhlu oluphakathi luluhlu lwemveliso ye-corrosion efanayo, kodwa kukho ukuqhekeka okucacileyo, kwaye i-ion ye-corrosion ingadlula kwiindawo eziqhekezayo kwaye ichithe i-substrate;umaleko wangaphakathi ngumaleko oshinyeneyo wemveliso ngaphandle kokuqhekeka okucacileyo, onesiphumo esihle sokukhusela kwi-substrate.Phantsi kwemeko ye-200 × yoqobo yoxinaniso lwesisombululo somhlwa (umzobo 3c), umaleko wokutya kumphezulu wesampulu unokwahlulwa ube ngamacandelo amathathu: umaleko ongaphandle ngumaleko obhityileyo kunye nofanayo;umaleko ophakathi ubukhulu becala i-petal-shaped and flake-shaped corrosion Umaleko wangaphakathi ngumaleko oshinyeneyo wemveliso ngaphandle kokuqhekeka okucacileyo kunye nemingxuma, enefuthe elihle lokukhusela kwi-substrate.
Ingabonwa kwi-Fig. 3d ukuba kwindawo efaniswayo ye-corrosion ye-pH 3.5, kukho inani elikhulu leemveliso ze-flocculent okanye njengenaliti ezifana ne-corrosion kwi-surface ye-20MnTiB yomfanekiso we-bolt high-strength. iintanda.
Inokubonwa kumfanekiso we-3f ukuba xa ubushushu bonyuka ukuya kuma-50 °C, akukho maleko exineneyo yangaphakathi efunyenweyo kwisakhiwo somaleko we-corrosion, ebonisa ukuba kukho izikhewu phakathi kwamaleko e-corrosion kwi-50 °C, nto leyo eyenza ukuba i-substrate ingagqunywanga ngokupheleleyo yimveliso ye-corrosion.Ibonelela ngokhuseleko ekwandeni kokutya komhlwa kwi-substrate.
Iipropathi zoomatshini zeebholithi zokuqina okuphezulu phantsi koxinzelelo loxinzelelo loxinzelelo oluqhubekayo kwiindawo ezahlukeneyo ezinomhlwa zibonisiwe kwiTheyibhile 2:
Inokubonwa kwiThebhile yesi-2 ukuba iipropathi zoomatshini ze-20MnTiB zesampulu zamandla aphezulu ebholiti zisahlangabezana neemfuno ezisemgangathweni emva kokuba umjikelo owomileyo-manzi ukhawulezise uvavanyo lwe-corrosion kwiindawo ezahlukeneyo ezifaniswayo ze-corrosion, kodwa kukho umonakalo othile xa kuthelekiswa ne-uncorroded ones.sample.K I-00 × i-concentration yesisombululo esifanisiweyo, i-elongation yesampuli iyancipha kakhulu.Iimpawu zomatshini zifana nokugxininiswa kwe-20 × kunye ne-200 × izisombululo ze-corrosion zangaphambili ezifaniswayo.Xa ixabiso le-pH yesisombululo esilinganisiweyo se-corrosion yehla ukuya kwi-3.5, amandla okuqina kunye nokuphakama kweesampuli zehla kakhulu. kufutshane kakhulu kwixabiso eliqhelekileyo.
I-morphology ye-fracture ye-20MnTiB i-bolt high-strength-bolt stress corrosion specimens phantsi kweendawo ezahlukeneyo zokubola ziboniswa kwi-Figure 4, eyi-macro-morphology ye-fracture, i-fiber zone embindini we-fracture, i-micro-morphological lip ye-shear interface, kunye nomphezulu wesampuli.
I-Macroscopic kunye ne-microscopic fracture morphologies ye-20MnTiB imizekelo yebholithi yamandla aphezulu kwiindawo ezahlukeneyo ezifaniswayo ze-corrosion (500×): (a) akukho mhlwa;(b) ixesha eli-1;(c) 20 ×;(d) 200 ×;(e) pH3.5;(f) pH7.5;(g) 50°C.
Inokubonwa kwi-Fig. 4 ukuba ukwaphuka kwe-20MnTiB high-strength bolt bolt stress corrosion specimen phantsi kweendawo ezahlukeneyo ezifaniswayo ze-corrosion zibonakalisa i-cup-cone fracture eqhelekileyo.Xa kuthelekiswa ne-specimen engabonakaliyo (Umfanekiso we-4a), indawo ephakathi kwendawo yefiber crack incinci., indawo yomlomo we-shear inkulu.Oku kubonisa ukuba iimpawu zoomatshini zezixhobo zonakaliswe kakhulu emva kokugqwala.Ngokunyuka koxinzelelo lwesisombululo esifanisiweyo, imingxuma kwindawo ye-fiber kwindawo yokwaphuka yanda, kwaye i-seams yokukrazula ecacileyo yavela. zazininzi iimveliso zomhlwa kumphezulu.isampulu.
Kucatshulwa kwi-Figure 3d ukuba kukho ukuqhekeka okucacileyo kwi-corrosion layer kwi-surface yesampuli, engenalo impembelelo efanelekileyo yokukhusela kwi-matrix.Kwisisombululo se-corrosion esifanisiweyo se-pH 3.5 (Umfanekiso we-4e), umphezulu wesampuli ugxininiswe kakhulu, kwaye indawo yefiber ephakathi ngokucacileyo incinci., Kukho inani elikhulu leengqungquthela ezingaqhelekanga zokukrazula kumbindi wendawo yefiber.Ngokonyuka kwexabiso le-pH yesisombululo sokutya esifanisiweyo, indawo yokukrazula kwindawo yefiber ephakathi kweqhekeza iyancipha, umgodi uyancipha ngokuthe ngcembe, kwaye ubunzulu bomgodi buyancipha ngokuthe ngcembe.
Xa ubushushu bonyuka ukuya kuma-50 ° C (umzobo 4g), indawo yomlomo wokucheba yokwaphuka kwesampulu yayiyeyona inkulu, imingxuma kwindawo yefiber esembindini yanda kakhulu, kwaye ubunzulu bomngxuma banda, kwaye ujongano phakathi komphetho womlomo wokucheba kunye nomphezulu wesampulu yanda.Iimveliso ze-Corrosion kunye nemingxuma ziye zanda, nto leyo eqinisekisa indlela enzulu ye-corrosion ye-substrate eboniswe kwi-Fig. 3f.
Ixabiso le-pH yesisombululo se-corrosion liya kubangela umonakalo kwiipropati zomatshini we-20MnTiB iibholiti zamandla aphezulu, kodwa umphumo awubalulekanga.Kwisisombululo se-corrosion ye-pH 3.5, inani elikhulu lemveliso ye-flocculent okanye yeenaliti ezinjenge-corrosion zisasazwa kumphezulu wesampuli, kunye ne-corrosion, i-corrosion ye-corrosion ye-substrate ecacileyo ayinakukhuselwa kwaye i-corrosion ifake i-substrate ebonakalayo. inani elikhulu leemveliso ze-corrosion kwi-microscopic morphology ye-sample fracture.Oku kubonisa ukuba ukukwazi kwesampulu ukuxhathisa ukuguqulwa kwamandla angaphandle kuncitshiswe kakhulu kwindawo ene-acidic, kwaye iqondo loxinzelelo lwe-corrosion tyency of the material yanda kakhulu.
Isisombululo somhlwa sokuqala esifanisiweyo sasinempembelelo encinci kwiimpawu zoomatshini zeesampulu eziphezulu zamandla, kodwa njengoko uxinaniso lwesisombululo esilinganisiweyo se-corrosion sanda saya kumaxesha angama-20 eso sisombululo somhlwa owenziweyo, iimpawu zomatshini zeesampulu zonakaliswe kakhulu, kwaye kwakukho ukubola okucacileyo kwi-fracture microstructure.imingxunya, iintanda zesibini kunye neemveliso ezininzi zokuhlwa.Xa i-corrosion solution efanisiweyo yoxinaniso yanda ukusuka kumaxesha angama-20 ukuya kumaxesha angama-200 oxinaniso lwesisombululo se-corrosion yasekuqaleni, umphumo wesisombululo se-corrosion concentration kwiipropati ze-mechanical of the material was weak.
Xa ubushushu obulinganisiweyo bomhlwa bungama-25℃, amandla esivuno kunye namandla okuqina e20MnTiB imizekelo yebholithi yamandla aphezulu ayitshintshi kakhulu xa ithelekiswa nesampulu engagqwaliyo. Nangona kunjalo, phantsi kobume obulinganisiweyo bomhlwa obuyi-50 °C, amandla okuqina kunye nokwandiswa komgangatho wesampulu yehla kakhulu, inqanaba lesampulu liye lancipha kakhulu, umgangatho wesampulu wawucuthe kakhulu. , kwaye kwakukho i-dimples kwindawo ye-fiber ephakathi.Kunyuswe ngokuphawulekayo, ubunzulu bomgodi bunyukile, iimveliso zomhlwa kunye nemigodi ye-corrosion yanda.Oku kubonisa ukuba ubushushu be-synergistic corrosion bume bunempembelelo enkulu kwiimpawu zoomatshini ze-bolts zamandla aphezulu, ezingabonakali kwiqondo lokushisa, kodwa kubaluleke ngakumbi xa ubushushu bufikelela kwi-50 °C.
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