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Indlela entsha esekelwe kwi-laser ekhethiweyo yokunyibilika ukulawula i-microstructure yeemveliso kwinkqubo yokuvelisa iphakanyisiwe.Umatshini uxhomekeke kwisizukulwana samaza aphezulu e-ultrasonic kwi-pool etyhidiweyo yi-complex intensity-modulated laser irradiation.Izifundo zovavanyo kunye nokulinganisa kwamanani kubonisa ukuba le ndlela yokulawula inokwenzeka ngokobugcisa kwaye inokusebenza ngokufanelekileyo kwi-laser yoyilo loyilo.
Imveliso eyongeziweyo (AM) yeendawo ezinokwakheka okuntsokothileyo iye yanda kakhulu kumashumi eminyaka akutshanje. Nangona kunjalo, nangona kukho iintlobo ngeentlobo zeenkqubo zokuvelisa ezongezelelweyo, kubandakanywa ukunyibilika kwe-laser ekhethiweyo (SLM) 1,2,3, i-laser ethe ngqo ye-metal deposition4,5,6, i-electron beam melting7,8 kunye nabanye9,10, aMacandelo anokuba nesiphene. amaxabiso, kunye nobunzima bomjikelezo wokufudumeza ekunyibilikeni kunye nokunyibilika kwezinto eziphathekayo 11, okukhokelela ekukhuleni kwengqolowa ye-epitaxial kunye ne-porosity ebalulekileyo.I-12,13 ibonise ukuba kuyimfuneko ukulawula i-gradients ye-thermal, amazinga okupholisa, kunye nokubunjwa kwe-alloy, okanye ukusebenzisa ukutshatyalaliswa komzimba okongeziweyo ngamasimi angaphandle eepropati ezahlukeneyo, ezifana ne-ultrasound, ukufezekisa izakhiwo zengqolowa ezilinganayo.
Upapasho oluninzi lujongene nefuthe lonyango lwe-vibration kwinkqubo yokuqinisa kwiinkqubo eziqhelekileyo zokuphosa14,15.Nangona kunjalo, ukusebenzisa intsimi yangaphandle kwi-bulk melt ayivelisi i-microstructure yezinto ezifunwayo.Ukuba umthamo wesigaba solwelo sincinci, imeko iyatshintsha kakhulu.Kule meko, intsimi yangaphandle ichaphazela kakhulu inkqubo yokuqinisa. ,25,26,27, arc stirring28 kunye ne-oscillation29, iziphumo ze-electromagnetic ngexesha le-pulsed plasma arcs30,31 kunye nezinye iindlela32 ziye zaqwalaselwa .Namathisela kwi-substrate usebenzisa umthombo wangaphandle ophezulu we-ultrasound we-ultrasound (nge-20 kHz) .I-ultrasound-induced ultrasound-induced arcs i-constitution to constitutement eyongeziweyo ye-grain ephuculweyo kwi-constitutement eyongeziweyo ye-grain ephuculweyo kwi-constitutement eyongeziweyo ye-grain ephuculweyo. ukuvelisa iikristale ezintsha nge-cavitation.
Kulo msebenzi, siye saphanda ukuba kunokwenzeka ukuguqula ukwakheka kweenkozo ze-austenitic stainless steels ngokufaka i-sonicating pool etyhidiweyo kunye namaza omsindo avela kwi-melting laser ngokwayo.I-intensity modulation yesiganeko se-laser radiation kwi-light-absorbing medium iziphumo ekuvelweni kwamaza e-ultrasonic, aguqula i-microstructure ye-microstructure ye-radiation ye-sLMD ekhoyo ngokulula. s kulo msebenzi zenziwa kwiipleyiti zentsimbi ezingenasici eziye zavezwa kwimitha ye-laser ene-intensity-modulated. Ngoko ke, ngobuchwephesha, unyango lomphezulu we-laser lwenziwa. Nangona kunjalo, ukuba unyango lwe-laser olunjalo lwenziwa kumphezulu womaleko ngamnye, ngexesha lokwakhiwa kwe-laser-by-layer, iziphumo kuwo wonke umthamo okanye kwiindawo ezikhethiweyo zomthamo ziyafezekiswa.Ngamanye amazwi, ukuba inxalenye ye-laser yonyango lwe-laser yenziwa kumphezulu we-laser.
Nangona kwi-ultrasonic uphondo olusekelwe kunyango lwe-ultrasonic, amandla e-ultrasonic yomsindo wesandi omileyo ahanjiswa kulo lonke icandelo, ngelixa i-laser-induced intensity ye-ultrasonic igxininiswe kakhulu kufuphi nendawo apho i-laser radiation ibanjwe khona. Uxinzelelo lwe-coustic lusondele kwi-zero kwaye i-particle velocity inomlinganiselo ophezulu we-amplitude phezu kwendawo yonke ephezulu yecala. Uxinzelelo lwesandi ngaphakathi kwi-pool yonke etyhidiweyo ayikwazi ukudlula i-0.1% yoxinzelelo oluphezulu oluveliswa yintloko ye-welding, kuba i-wavelength yamaza e-ultrasonic kunye ne-frequency ye-20 kHz kwi-stainless steel stainless is \ (~\ sim) ngokuqhelekileyo i-(~\ sim 0). \umbhalo {mm}\) Ngoko ke, umphumo we-ultrasound kwi-cavitation unokuba yincinci.
Kufuneka kuqatshelwe ukuba ukusetyenziswa kwemitha ye-laser ene-intensity-modulated intestination laser metal deposition yindawo esebenzayo yophando35,36,37,38.
Iziphumo thermal isiganeko laser radiation kwi medium sisiseko phantse zonke izixhobo laser processing izinto 39, 40, ezifana nokusika 41, welding, ukuqina, ukomba 42, ukucocwa umphezulu, ingxubevange umphezulu, ukugudisa umphezulu 43, etc.materials processing technology kunye neziphumo preliminary isishwankathelo ezininzi reviews kunye monographs 5, 44, 46, 46.
Kufuneka kuqatshelwe ukuba nasiphi na isenzo esingenasigxina kwi-medium, kubandakanywa isenzo se-lasing kwi-absorbe medium, kubangela ukuvuswa kwamaza e-acoustic kuyo ngokusebenza okungaphezulu okanye ngaphantsi.Ekuqaleni, eyona nto yayigxininisekile kwi-laser excitation yamaza kulwelo kunye neendlela ezahlukeneyo zokukhupha i-thermal yesandi (ukwandiswa kwe-thermal, u-evaporation, ukuguqulwa kwevolumu, i-contract4 ye-monorous, i-monograph4, njl. I-s50, 51, 52 ibonelela ngocazululo lwethiyori yale nkqubo kunye nokusetyenziswa kwayo okunokwenzeka.
Le micimbi yaxoxwa emva koko kwiinkomfa ezahlukeneyo, kwaye i-laser excitation ye-ultrasound inezicelo kuzo zombini izicelo zoshishino lwe-laser technology53 kunye neyeza54.Ngoko ke, kunokuqwalaselwa ukuba ingcamango eyisiseko yenkqubo apho i-pulsed laser light acts on an absorbing medium iye yasekwa.Ukuhlolwa kwe-Laser ultrasonic kusetyenziselwa ukufumanisa i-defect ye-SLM-eyenziwe,55 iisampuli5.
Umphumo wamaza othusayo owenziwe ngelaser kwizinto sisiseko somothuko welaser peening57,58,59, ekwasetyenziselwa unyango olungaphezulu lweengxenye ezenziwe ezongezelelweyo60.Nangona kunjalo, ukomeleza ukothusa kwelaser kusebenza kakhulu kwiipulses laser nanosecond kunye neendawo ezilayishwe ngoomatshini (umz., kunye nomaleko wolwelo)59 kuba ukulayishwa koomatshini kwandisa incopho yoxinzelelo.
Iimvavanyo zenziwe ukuphanda imiphumo enokubakho yemimandla eyahlukeneyo ebonakalayo kwi-microstructure yezinto eziqinisiweyo.Umzobo osebenzayo wokuseta uvavanyo uboniswe kuMzobo 1.I-pulsed Nd: YAG i-solid-state laser esebenza kwimo esebenza ngokukhululekileyo (ubude be-pulse \ (\ tau _L \ sim 150 ~ \ upmu \ i-pulse engathathi hlangothi) isetyenzisiwe kunye ne-laser engathathi hlangothi isetyenzisiweyo. Inkqubo yepleyiti ye-splitter. Ngokuxhomekeke kwindibaniselwano yezihluzo zoxinaniso ezingathathi hlangothi, amandla e-pulse ekujoliswe kuwo ayahluka ukusuka kwi-(E_L \ sim 20 ~\text {mJ}\) ukuya \(E_L \ sim 100 ~\text {mJ}\) .I-laser beam ebonakaliswe kwi-beam splitter ifakwe kwi-photodiodi yedatha ye-photositane kunye ne-photodiodi yedatha ende kunye ne-photodiodi yedatha edlulileyo kunye nexesha elide le-calodiodi yempendulo kunye nedatha ye-photodiodi egqithisiweyo. ing \(1~\text {ms}\)) zisetyenziselwa ukugqiba isiganeko ukuya kwaye ibonakaliswe kwithagethi, kunye neemitha zamandla amabini (photodiodes kunye namaxesha amafutshane okuphendula \ (<10~\text {ns}\)) ukumisela isiganeko kunye nokubonakalisa amandla okukhanya.Iikhalorimitha kunye neemitha zamandla zilinganiswe ukunika amaxabiso kwiiyunithi ezipheleleyo zisebenzisa i-30 i-diselectric ye-XLP-2-D i-XLP-Elec ye-3 kunye ne-XLP-D detector ye-XLP-2-H. isibuko sifakwe kwindawo yesampula.Gxininisa umqadi kwithagethi usebenzisa i-lens (i-Antireflection coating kwi \ (1.06 \ upmu \ text {m}\), ubude befocal \ (160 ~\text {mm}\)) kunye nesinqe se-beam kwindawo ekujoliswe kuyo 60– \ (100 ~\upmu\text {m}\).
Umzobo weskimu esisebenzayo sokusekwa kovavanyo: 1-laser;2-i-laser beam;3-ifiltha yoxinaniso engathathi hlangothi;4-i-synchronized photodiode;5-umhlukanisi we-beam;6-diaphragm;I-7-calorimeter ye-beam yesiganeko;I-8 - i-calorimeter ye-beam ebonakalisiweyo;I-9 - imitha yamandla yombane yesiganeko;I-10 - imitha yamandla e-beam ebonakalisiweyo;I-11 - i-lens yokugxila;I-12 - isipili;I-13 - isampuli;I-14 - i-broadband piezoelectric transducer;15 – 2D converter;I-16 - i-microcontroller yokubeka;I-17 - iyunithi yongqamaniso;I-18 - inkqubo yokufumana idijithali ye-multi-channel enemilinganiselo eyahlukeneyo yesampuli;I-19 - ikhompyuter yakho.
Unyango lwe-Ultrasonic lwenziwa ngolu hlobo lulandelayo.I-laser isebenza kwimodi yokukhulula;ke ngoko ixesha le-laser pulse yi \(\tau _L \ sim 150~\upmu \text {s}\), ebandakanya ubuninzi bexesha elimalunga ne-(1.5~\upmu \ text {s} \) nganye.Imilo yethutyana ye-laser pulse kunye ne-spectrum yayo ibandakanya i-low-frequency ye-frequency kunye ne-high-frequency ye-envelope kunye ne-envelope ephantsi umbhalo {MHz} \), njengoko kubonisiwe kuMfanekiso 2.- Imvulophu yefrikhwensi ibonelela ngokufudumeza kunye nokunyibilika okulandelayo kunye nokunyuka kwezinto eziphathekayo, ngelixa icandelo eliphezulu le-frequency libonelela ngee-vibrations ze-ultrasonic ngenxa yempembelelo ye-photoacoustic.I-waveform ye-pulse ye-ultrasonic eyenziwa yi-laser igxininisekile ngokukodwa ngokubunjwa kwexesha le-laser pulse intensity.Isuka \(7~\text {kHz}\) ukuya \ (2~\text {MHz}\), kwaye i-frequency center is \(~ 0.7~\text {MHz}\) eqhelekileyo ye-laser yemowudi esebenza simahla.
Ukuhanjiswa kwexeshana kwe-laser pulse intensity (a) kunye nesantya sesandi (b) kumphezulu ongemva wesampulu, i-spectra (igophe elibhlowu) ye-laser pulse enye (c) kunye ne-ultrasound pulse (d) ephakathi kwama-300 laser pulses (igophe elibomvu) .
Siyakwazi ukuhlukanisa ngokucacileyo i-low-frequency kunye ne-high-frequency components yonyango lwe-acoustic ehambelana nemvulophu ye-low-frequency ye-laser pulse kunye ne-high-frequency modulation, ngokulandelanayo.Ubude be-acoustic wave wave wavely by laser pulse envelope idlula \(40 ~\text {cm});ngoko ke, umphumo ophambili we-broadband high-frequency components of the acoustic signal kwi-microstructure kulindeleke.
Iinkqubo eziphathekayo kwi-SLM ziyinkimbinkimbi kwaye zenzeke ngexesha elifanayo kwimilinganiselo eyahlukeneyo yendawo kunye neyexeshana.Ngoko ke, iindlela ezininzi ze-multi-scale zifaneleke kakhulu kuhlalutyo lwethiyori ye-SLM.Iimodeli zemathematika kufuneka ziqale zibe yi-multi-physical.I-mechanics kunye ne-thermophysics ye-multiphase medium "i-solid-liquid melt" isebenzisana kunye ne-belt loading esebenzayo kwi-smommal i-smodium echazwe emva koko i-speciation ye-inert iyakwazi ukulandela i-gas esebenzayo.
Amazinga okufudumeza kunye nokupholisa ukuya kuthi ga \(10^6~\text {K}/\text {s}\) /\text{ ngenxa yokukhanya kwelaser yendawo kunye noxinzelelo lwamandla ukuya kuthi ga \(10^{13}~\text {W} cm}^2\).
Umjikelo we-melting-solidification uhlala phakathi kwe-1 kunye \(10~\text {ms}\), enegalelo ekuqiniseni ngokukhawuleza kwendawo yokunyibilika ngexesha lokupholisa.
Ukufudumeza ngokukhawuleza kwesampulu yesampula kubangela ukubunjwa koxinzelelo oluphezulu lwe-thermoelastic kwi-surface layer.Ukwaneleyo (ukuya kwi-20%) inxalenye ye-powder layer i-evaporated kakhulu63, ephumela kumthwalo woxinzelelo olongezelelweyo phezu komhlaba ekuphenduleni ukukhutshwa kwe-laser. amaza amaza asasaza ukusuka kumphezulu ukuya kwi-substrate.Ukuze ufumane idatha echanekileyo yobungakanani boxinzelelo lwendawo kunye nokusabalalisa ukuxhatshazwa, ukulinganisa i-mesoscopic yengxaki ye-elastic deformation edityaniswe nobushushu kunye nokudluliselwa kobuninzi kuyenziwa.
Iequation ezilawulayo zemodeli zibandakanya (1) i-equations yokudlulisa ubushushu engazinzanga apho ukuhanjiswa kwe-thermal kuxhomekeke kwimo yesigaba (umgubo, ukunyibilika, i-polycrystalline) kunye nobushushu, (2) ukuguquguquka kwe-elastic deformation emva kokukhutshwa okuqhubekayo kunye ne-equation yokwandisa i-thermoelastic. x.I-mass flux ichazwa ngokusekelwe ekubalweni koxinzelelo lomphunga ogcweleyo wezinto eziphumayo.I-elastoplastic stress-strain relationship isetyenziswa apho i-thermoelastic stress is proportional to the temperature difference.Kumandla aqhelekileyo \(300~\text {W}\), frequency \(10^5~\text {Hz~e&0}, intermit {0} kunye ne-0) i-diameter ye-beam esebenzayo.
Umzobo wesi-3 ubonisa iziphumo zokulinganisa kwamanani ommandla otyhidiweyo kusetyenziswa imodeli yemathematika enkulu. Ububanzi bommandla wodibaniso yi \(200~\upmu \text {m}\) (\(100~\upmu \text { m}\) radius) kunye \(40~\upmu \text{m}~) ibonisa ubunzulu bexesha (0) njengobunzulu bexesha le-K kunye nomlinganiso we-K wendawo (0) \) ngenxa yenqanaba eliphezulu eliphakathi lokumodareyitha kwepulse.Izinga lokufudumeza \(V_h\) kunye nokupholisa \(V_c\) zingolandelelwano lwe-\(10^7\) kunye \(10^6~\text {K}/\text {s}\), ngokulandelelanayo.La maxabiso ahambelana kakuhle nohlahlelo lwethu lwangaphambili lwe-mag(V_) kunye nohlalutyo lwe-mag(V) lwangaphambili lwe-mag (V_) ukugqithiswa ngokukhawuleza komgangatho ongaphezulu, apho ukuqhutyelwa kwe-thermal kwi-substrate akwanelanga ukususa ubushushu.Ngoko ke, kwi-(t=26 ~\upmu \text {s}\) iqondo lokushisa elingaphezulu liphezulu njenge \(4800 ~\text {K}\) .Ukunyuka okunamandla kwezinto kunokubangela ukuba umgangatho wesampuli uthotyelwe phantsi koxinzelelo olugqithisileyo kunye ne-peel off.
Iziphumo zokulinganisa iinombolo zommandla wokunyibilika we-laser enye yepulse annealing kwi-316L yesampuli yeplate. Ixesha ukusuka ekuqaleni kwe-pulse ukuya kubunzulu be-pool etyhidiweyo ukufikelela kwixabiso eliphezulu \ (180 ~ \ upmu \ text {s} \) .I-isotherm \ (T = T_L = 1723 ~.) imele i-liquid boundary (i-solid boundary) (i-solid boundary) imele i-solid boundary. ihambelana noxinzelelo lwesivuno olubalwe njengomsebenzi weqondo lokushisa kwicandelo elilandelayo.Ngoko ke, kwi-domain phakathi kwe-isolines ezimbini (i-isotherms \ (T = T_L \) kunye ne-isobars \ (\ sigma =\ sigma _V (T) \)), isigaba esiqinileyo sixhomekeke kwimithwalo eqinile yomatshini , enokuthi ibangele utshintsho kwi-microstructure.
Esi siphumo sichazwa ngakumbi kwi-Figure 4a, apho inqanaba loxinzelelo kwindawo etyhidiweyo icwangciswe njengomsebenzi wexesha kunye nomgama ukusuka phezulu.Okokuqala, ukuziphatha koxinzelelo kuhambelana nokumodareyithwa kwe-laser pulse intensity echazwe kwi-Figure 2 ngasentla.Uxinzelelo oluphezulu \umbhalo{s}\) malunga ne-(10 ~\ text {MPa}~ d, c, i-fluid yasekhaya, ibonwe kwindawo ye-2. Uxinzelelo kwindawo yokulawula ineempawu ze-oscillation ezifanayo njenge-frequency \ (500 ~\ text {kHz} \) .Oku kuthetha ukuba amaza oxinzelelo lwe-ultrasonic aveliswa phezulu aze asasaze kwi-substrate.
Iimpawu ezibaliweyo zommandla we-deformation kufuphi ne-melting zone ziboniswa kwi-Fig. ukuya kuxinzelelo lwangaphezulu.Olu xinzelelo lwenzeka ngenxa yokuchithwa kwe-laser, kwaye akukho xinzelelo lwe-thermoelastic lubonwa kwiindawo zokulawula ngenxa yokuba indawo yokuqala echaphazelekayo ukushisa yayincinci kakhulu.Xa ubushushu buchithwa kwi-substrate, indawo yokulawula ivelisa uxinzelelo oluphezulu lwe-thermoelastic ngasentla \(40 ~\text {MPa}\).
Amanqanaba oxinzelelo afunyenweyo anefuthe elibalulekileyo kwi-interface eqinile-emanzi kwaye inokuba yindlela yokulawula elawula indlela yokuqinisa.Ubungakanani bendawo yokuguqula i-2 ukuya ku-3 amaxesha amakhulu kunommandla we-melting.Njengoko kuboniswe kwi-Figure 3, indawo ye-isotherm encibilikayo kunye nenqanaba loxinzelelo olulingana noxinzelelo lwemveliso olusebenzayo kunye nomthwalo osebenzayo wendawo i-laser i-diameter esebenzayo inika i-laser i-diameter ephezulu ifaniswe. 300 kunye \(800~\upmu \okubhaliweyo {m}\) ngokuxhomekeke kwixesha elingoko nangoko.
Ngako oko, ukumodareyitha okuyinkimbinkimbi kwe-pulsed laser annealing kukhokelela kwisiphumo se-ultrasonic.Indlela yokukhethwa kwe-microstructure iyahluka xa ithelekiswa ne-SLM ngaphandle kokulayisha i-ultrasonic.Imimandla engazinzanga ephosakeleyo ikhokelela kwimijikelezo ye-periodic yokunyanzeliswa kunye nokwelula kwisigaba esiqinileyo.Ngoko ke, ukubunjwa kwemida emitsha yeenkozo kunye nemida ye-subgrain iyahluka xa kuthelekiswa ne-SLM ngaphandle kokulayisha i-ultrasonic. ukuyila i-pulse modulation-induced ultrasound-driven SLM prototype.Kule meko, i-piezoelectric inductor 26 esetyenziswe kwenye indawo ingabandakanywa.
(a) Uxinzelelo njengomsebenzi wexesha, olubalwe kumgama owahlukileyo ukusuka kumphezulu 0, 20 kunye \(40~\upmu \okubhaliweyo {m}\) ecaleni kwe-axis ye-symmetry.(b) Uxinzelelo lwexesha likaVon Mises oluxhomekeke kwimatrix eqinileyo kwimigama 70, 120 kunye \(170~\upmu \\ upmu) okubhaliweyo
Iimvavanyo zenziwa kwi-AISI 321H iipleyiti zensimbi ezingenasici ezinemilinganiselo \ ( 20 \ amaxesha 20 \ amaxesha 5 ~ \ umbhalo {mm} \) .Emva kwe-laser pulse nganye, i-plate ihamba \ (50 ~\upmu \ text {m}\), kunye nesinqe se-laser kwindawo ekujoliswe kuyo malunga ne-(100 ~pm ukuya kwi-sub-upmu). bangela ukuxutywa kwezinto ezicutshungulwayo zokucoca ukutya okuziinkozo.Kuzo zonke iimeko, indawo edibeneyo yayiyi-sonicated, kuxhomekeke kwi-oscillatory component ye-laser radiation.Oku kuphumela ekunciphiseni okungaphezulu kwe-5-fold in average area grain.Umfanekiso 5 ubonisa indlela i-microstructure yengingqi ye-laser-melted iguquka kunye nenani lemijikelezo yokuphinda iphinde iphinde iphinde iphinde iphinde iphinde iphinde iphinde ibuyele.
Iziqendu (a,d,g,j) kunye (b,e,h,k) – microstructure of laser melted regions, subplots (c,f,i,l) - ukuhanjiswa kwendawo yeenkozo ezinemibala.I-Shading imele amasuntswana asetyenziselwa ukubala i-histogram.Imibala ihambelana nemimandla yeenkozo (jonga ibha yombala phezulu kwi-histogram. I-Subplots (ac) ihambelana nentsimbi engaxutywanga, kunye ne-subplots (df), (gi), (jl) ihambelana ne-1, 3 kunye ne-5 remelts.
Ekubeni i-laser pulse energy ayitshintshi phakathi kokudlula okulandelayo, ubunzulu bommandla otyhidiweyo bufana.Ngoko ke, umjelo olandelayo "ugubungela" ngokupheleleyo into yangaphambili.Nangona kunjalo, i-histogram ibonisa ukuba i-medium and median grain area iyancipha ngokunyuka kwenani lokupasa.Oku kungabonisa ukuba i-laser isebenza kwi-substrate kunokuba inyibilike.
Ukucocwa okuziinkozo kunokubangelwa kukupholisa ngokukhawuleza kwechibi elinyibilikisiweyo65.Enye iseti yemifuniselo yenziwa apho imiphezulu yeepleyiti zensimbi engenasici (321H kunye ne-316L) zaboniswa kwimitha yelaser eqhubekayo emoyeni (Fig. 6) kunye ne-vacuum (Fig. 7) I-Nd: i-laser ye-YAG kwimodi yokugijima yamahhala. Nangona kunjalo, isakhiwo esiqhelekileyo sekholomu sabonwa.
I-Microstructure ye-laser-melted region ye-laser wave wave (300 W amandla angapheliyo, i-200 mm / s scan speed, i-AISI 321H insimbi engenasici).
(a) I-Microstructure kunye (b) ne-electron backscatter diffraction image of the laser melting zone of vacuum i-wave wave laser (amandla ahlala e-100 W, isivinini sokuskena i-200 mm / s, i-AISI 316L insimbi engenasici) \ (\ sim 2 ~\ text {mbar} \).
Ngoko ke, kuboniswa ngokucacileyo ukuba i-modulation eyinkimbinkimbi ye-laser pulse intensity inefuthe elibalulekileyo kwi-microstructure. I-ultrasound ye-ultrasound kwizinto ezahlukeneyo ezibandakanya i-Ti-6Al-4V i-alloy 26 kunye nensimbi engenasici 34 isiphumo.Isixhobo esinokwenzeka sicingelwa ngolu hlobo lulandelayo.I-ultrasound enamandla ingabangela i-acoustic cavitation, njengoko kuboniswe kwi-ultrafast in situ synchrotron imaging ye-X-ray. Ukuwa kwe-cavitation yezinto eziphathekayo malunga ne-1 MP ifike kwi-bubbles, i-0 ifikelele kwi-bubbles yoxinzelelo malunga ne-0. }\) 69.Amaza othusayo anjalo anokuba namandla ngokwaneleyo ukukhuthaza ukubunjwa kwe-nuclei yesigaba esibalulekileyo sobungakanani obuqinileyo kulwelo oluninzi, ukuphazamisa ulwakhiwo oluqhelekileyo lwekholamu yenkozo yokwenziwa komaleko-ngamaleko okongezayo.
Apha, siphakamisa enye indlela ejongene nokuguqulwa kwesakhiwo nge-sonication enzulu. Izinto eziphathekayo emva nje kokuqiniswa kubushushu obuphezulu kufuphi nendawo yokunyibilikisa kwaye inoxinzelelo oluphantsi kakhulu lwesivuno. Amaza amakhulu e-ultrasonic angabangela ukuhamba kweplastiki ukuguqula isakhiwo senkozo yezinto ezishushu ezisanda kuqina.Nangona kunjalo, idatha yovavanyo ethembekileyo kwiqondo lokushisa lokuxhomekeka kwesivuno \ ~ (umbhalo we-150K ziyafumaneka kwi-" 8) .Ngoko ke, ukuvavanya i-hypothesis, senze i-molecular dynamics (MD) ukulinganisa ukwakheka kwe-Fe-Cr-Ni efana ne-AISI 316 L yentsimbi ukwenzela ukuvavanya ukuziphatha koxinzelelo lwesivuno kufuphi nendawo yokunyibilika.Ukubala uxinzelelo lwesivuno, sasebenzisa ubuchule be-MD shear stress relaxation echazwe kwi-70, 71, i-interculation ye-71, i-2, i-interculation, i-2, i-2, i-interculations, i-2, i-2. Umzekelo we-tomic (EAM) ukusuka kwi-74.MD ukulinganisa kwenziwa ngokusebenzisa iikhowudi ze-LAMMPS 75,76.Iinkcukacha zokulinganisa i-MD ziya kupapashwa kwenye indawo.Iziphumo zokubala ze-MD zoxinzelelo lwesivuno njengomsebenzi weqondo lokushisa ziboniswa kwi-Fig. 8 kunye nedatha yovavanyo ekhoyo kunye nolunye uvandlakanyo77,78,79,828.
Uxinzelelo lwesivuno kwibakala le-AISI grade 316 i-austenitic stainless steel kunye nokwakheka kwemodeli ngokuchasene nobushushu bokulinganisa kwe-MD. Imilinganiselo yovavanyo evela kwiimbekiselo: (a) 77, (b) 78, (c) 79, (d) 80, (e) 81. bhekisa kwi. .Iziphumo ezinkulu ze-MD zokulinganisa kolu phando zichazwe njenge \ (\ vatriangleleft \) kwikristale engenasiphene engenasiphelo kunye \ (\ vatriangleright \) yeenkozo ezinqamlekileyo zithathela ingqalelo ubungakanani bengqolowa obuyi-avareji ngokusebenzisa i-Holo-Petch relation Dimensions\(d = 50~\upmu \text {m}\).
Kungabonwa ukuba \ (T> 1500 ~ \ umbhalo {K} \) isivuno soxinzelelo lwehla ngezantsi \ (40 ~ \ umbhalo {MPa} \) . Ngakolunye uhlangothi, uqikelelo luqikelele ukuba i-laser-generated ultrasonic amplitude idlula \ (40 ~ \ text {MPa} \) (jonga umzobo 4b), owaneleyo ukuhamba kwezinto eziqinileyo kwiplastiki eshushu.
Ukwakhiwa kwe-microstructure ye-12Cr18Ni10Ti (AISI 321H) i-austenitic stainless steel ngexesha le-SLM yaphandwa ngovavanyo kusetyenziswa umthombo we-laser we-pulsed intensity-modulated.
Ukunciphisa ubungakanani beenkozo kwindawo yokunyibilika kwe-laser kufunyenwe ngenxa ye-laser remelting eqhubekayo emva kokudlula kwe-1, i-3 okanye i-5.
Imodeli yeMacroscopic ibonisa ukuba ubungakanani obuqikelelweyo bommandla apho i-ultrasonic deformation inokuchaphazela ngokuqinisekileyo i-frontification front ifikelela kwi-(1~\text {mm}\).
Imodeli ye-MD ye-microscopic ibonisa ukuba amandla okuvelisa i-AISI 316 i-austenitic stainless steel iyancipha kakhulu kwi-(40 ~\ text {MPa} \) kufuphi ne-melting point.
Iziphumo ezifunyenweyo zicebisa indlela yokulawula i-microstructure yezixhobo usebenzisa i-modulated laser processing kwaye inokusebenza njengesiseko sokudala utshintsho olutsha lwe-pulsed SLM ubuchule.
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