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Kuhlongozwa indlela entsha esekelwe ekuncibilikeni kwe-laser okukhethiwe ukuze kulawulwe i-microstructure yemikhiqizo enqubweni yokukhiqiza.Umshini uncike ekusungulweni kwamagagasi e-ultrasonic anamandla kakhulu echibini elincibilikisiwe nge-laser irradiation eyinkimbinkimbi.Izifundo zokuhlola kanye nokulingiswa kwezinombolo kubonisa ukuthi le mishini yokulawula ingenzeka ngokobuchwepheshe futhi ingancibilika ngempumelelo emshinini wokukhetha i-laser.
Ukukhiqiza okungeziwe (AM) kwezingxenye eziyinkimbinkimbi ezimise okwezimo eziyinkimbinkimbi kuye kwakhula kakhulu emashumini eminyaka amuva nje. Nokho, naphezu kwezinqubo ezihlukahlukene zokukhiqiza izithasiselo, okuhlanganisa ukukhetha kwe-laser melting (SLM)1,2,3, i-laser metal deposition eqondile4,5,6, i-electron beam melting7,8 nezinye9,10, Izingxenye zingase zibe nesici. rates, kanye yinkimbinkimbi yokushisa imijikelezo ekuncibilikeni nasekubuyiseleni izinto ezibonakalayo 11, okuholela ekukhuleni okusanhlamvu kwe-epitaxial kanye ne-porosity ebalulekile.I-12,13 ibonise ukuthi kuyadingeka ukulawula ama-gradients ashisayo, amazinga okupholisa, nokwakheka kwe-alloy, noma ukusebenzisa ukushaqeka okungeziwe ngokomzimba ngezinkambu zangaphandle zezakhiwo ezihlukahlukene, njenge-ultrasound, ukuze kuzuzwe izakhiwo zokusanhlamvu ezilinganayo.
Izincwadi eziningi ziphathelene nomphumela wokwelashwa kokudlidliza enqubweni yokuqiniswa ezinqubweni zokusakaza ezivamile14,15.Nokho, ukusebenzisa inkambu yangaphandle ekuncibilikeni kwenqwaba akukhiqizi i-microstructure yezinto oyifunayo.Uma umthamo wesigaba se-liquid uncane, isimo sishintsha kakhulu.Kulokhu, inkambu yangaphandle ithinta kakhulu inqubo yokuqinisa.Intense,19,26,21,21 ,25,26,27, i-arc stirring28 kanye ne-oscillation29, imiphumela kagesi ngesikhathi se-pulsed plasma arcs30,31 nezinye izindlela32 ziye zacatshangelwa .Namathisela ku-substrate usebenzisa umthombo wangaphandle we-ultrasound we-high-intensity ultrasound (ku-20 kHz).I-ultrasound-induced ultrasound-induced plasma arcs30,31 kanye nezinye izindlela32 ziye zacatshangelwa .Namathisela ku-substrate usebenzisa umthombo wangaphandle we-ultrasound wamandla aphezulu (ku-20 kHz). ukukhiqiza amakristalu amasha ngokusebenzisa i-cavitation.
Kulo msebenzi, siphenye ukuthi kungenzeka yini ukuguqula ukwakheka kwezinhlamvu ze-austenitic stainless steels ngokwenza i-sonicating pool encibilikisiwe namagagasi omsindo akhiqizwe i-laser encibilikayo ngokwayo.Ukuguquguquka kokuqina kwesigameko semisebe ye-laser endaweni emunca ukukhanya kuphumela ekukhiqizeni amaza e-ultrasonic, ashintsha i-microstructure ye-microstructure ye-radiation ye-SLMD ehlanganisiwe kalula. s kulo msebenzi zenziwa ezingcwecweni zensimbi engagqwali okuvele kwazo kudalulwe emisebeni ye-laser eshintshiwe ngamandla. Ngakho-ke, ngobuchwepheshe, ukwelashwa kwe-laser surface kwenziwa. Nokho, uma ukwelapha okunjalo nge-laser kwenziwa phezu kwesendlalelo ngasinye, ngesikhathi sokwakhiwa kwe-lay-by-layer, imiphumela kuyo yonke ivolumu noma ezingxenyeni ezikhethiwe zevolumu ziyafinyelelwa. Ngamanye amazwi, uma ingxenye ye-laser yokwelapha i-laser yakhiwe ungqimba ngalunye lwelaser lwakhiwe.
Nakuba ku-ultrasonic horn-based ultrasonic therapy, amandla e-ultrasonic wegagasi lomsindo omile asatshalaliswa kuyo yonke ingxenye, kuyilapho amandla e-laser-induced ultrasonic agxile kakhulu eduze nendawo lapho imisebe ye-laser idonswa khona. ukucindezeleka kwe-coustic kuseduze ne-zero futhi isivinini sezinhlayiyana sine-amplitude enkulu phezu kwayo yonke indawo ephezulu yengxenye.Ingcindezi yomsindo ngaphakathi kwechibi elincibilikisiwe lonke ayikwazi ukudlula u-0.1% wengcindezi enkulu ekhiqizwa ikhanda lokushisela, ngenxa yokuthi ubude be-wavelength bamagagasi e-ultrasonic ne-frequency ye-20 kHz kunsimbi engagqwali yi-\(~\sim), ukujula okungaphansi kuka-0.(~\sim) ukujula kuka-0. \umbhalo {mm}\).Ngakho-ke, umphumela we-ultrasound ku-cavitation ungase ube mncane.
Kufanele kuqashelwe ukuthi ukusetshenziswa kwemisebe ye-laser eguquliwe ngamandla endaweni eqondile yensimbi ye-laser kuyindawo esebenzayo yocwaningo35,36,37,38.
Imiphumela eshisayo yesigameko semisebe ye-laser phakathi nendawo iyisisekelo sazo zonke izindlela zokucubungula izinto ezibonakalayo ze-laser 39, 40, njengokusika 41, ukushisela, ukuqina, ukubhoboza 42, ukuhlanzwa kwendawo, i-alloying ebusweni, ukupholisha ubuso 43, njll.ubuchwepheshe bokucubungula izinto kanye nemiphumela yokuqala efingqiwe ekubuyekezweni okuningi nama-monographs 5, 44, 46, 46.
Kufanele kuqashelwe ukuthi noma isiphi isenzo esingamile esiphakathi nendawo, okuhlanganisa isenzo sokuhlala endaweni emuncayo, siphumela ekuvusweni kwamagagasi e-acoustic kuwo ngokusebenza kahle okungaphezulu noma okuncane.Ekuqaleni, ukugxilwa okuyinhloko kwakuwukuvuswa kwe-laser kwamagagasi oketshezi kanye nezindlela ezihlukahlukene zokuvusa ukushisa okushisayo komsindo (ukunwetshwa okushisayo, ukuhwamuka, ukuguqulwa kwevolumu, ukushintshwa kwevolumu ye-4 monographi4, njll. s50, 51, 52 ihlinzeka ngokuhlaziywa kwethiyori yale nqubo kanye nokusetshenziswa kwayo okunokwenzeka.
Lezi zinkinga zaxoxwa kamuva ezingqungqutheleni ezihlukahlukene, futhi ukuvuthwa kwe-laser kwe-ultrasound kunezicelo kuzo zombili izinhlelo zokusebenza zezimboni ze-laser technology53 kanye nemithi54.Ngakho-ke, kungacatshangwa ukuthi umqondo oyisisekelo wenqubo lapho ukukhanya kwe-laser pulsed kusebenza endaweni emuncayo kuye kwasungulwa.Ukuhlolwa kwe-Laser ultrasonic kusetshenziselwa ukutholakala kokukhubazeka kwe-SLM-eyenziwe, amasampuli ama-56 akhiwe.
Umthelela wamagagasi okwethuka akhiqizwe nge-laser ezintweni ezisetshenziswayo uyisisekelo se-laser shock peening57,58,59, ephinde isetshenziselwe ukwelashwa okungaphezulu kwezingxenye ezikhiqizwa ngokwengeza60.Kodwa-ke, ukuqinisa ukushaqeka kwe-laser kusebenza kakhulu kumapulse we-nanosecond laser nasezindaweni ezilayishwe ngomshini (isb, ngongqimba loketshezi)59 ngoba ukulayisha ngomshini kwandisa inani eliphakeme kakhulu.
Ukuhlolwa kwenziwa ukuze kuphenywe imiphumela engaba khona yezinkambu ezibonakalayo ku-microstructure yezinto eziqinile.Umdwebo osebenzayo wokusethwa kokuhlola uboniswa kuMfanekiso 1.I-pulsed Nd:YAG solid-state laser esebenza ngemodi egijima mahhala (ubude be-pulse \(\tau _L \sim 150~\upmu \uchungechunge lusetshenzisiwe) bese kusetshenziswe isihlungi se-bensi pulse ngokusebenzisa i-bensi de lelaser {s}) I-am splitter plate system.Ngokuya ngenhlanganisela yezihlungi ze-neutral density, amandla okushaya kwenhliziyo kokuqondisiwe ayahluka ukusuka ku-\(E_L \sim 20~\text {mJ}\) ukuya ku-\(E_L \sim 100~\text {mJ}\) .I-laser beam evezwa kusihlukanisi se-beam inikezwa kudatha eyisifaniso, i-photodiodiquides yedlula i-photodiodi yesikhathi eside idlula i-photodiodiquide yesikhathi eside idlule ing \(1~\text {ms}\)) isetshenziselwa ukunquma isigameko ukuya nokuboniswa kusukela ekuqondisweni, kanye namamitha wamandla amabili (ama-photodiodes anezikhathi ezimfushane zokuphendula\(<10~\text {ns}\)) ukuze kunqunywe isigameko namandla okubona abonisiwe.Ama-caloriemeter namamitha wamandla kwalinganiswa ukuze kunikezwe amanani kumayunithi aphelele kusetshenziswa i-30-D-Spirit ye-D-Elec 3 i-XLP-D i-Thermo-D i-Thermo-D i-Thermos isibuko esifakwe endaweni yesampula.Gxilisa uhlaka phezu kwethagethi usebenzisa ilensi (I-antireflection coating kokuthi \(1.06 \upmu \text {m}\), ubude befocal \(160~\text {mm}\)) kanye nokhalo lwebhilidi endaweni eqondiwe 60– \(100~\upmu\text {m}\).
Umdwebo we-schematic osebenzayo wokusethwa kokuhlola: 1-laser;2 - ugongolo lwe-laser;3-i-neutral density filter;4—i-photodiode evumelanisiwe;5 - isihlukanisi sensimbi;6—i-diaphragm;I-7-calorimeter ye-beam yesigameko;8 - ikhalorimitha ye-beam ebonisiwe;I-9 - imitha yamandla we-beam yesigameko;I-10 - imitha yamandla e-beam ebonisiwe;I-11 - i-lens yokugxila;12 - isibuko;13 - isampula;14 - i-broadband piezoelectric transducer;15 – 2D converter;16 - ukubeka i-microcontroller;17 – iyunithi yokuvumelanisa;18 – uhlelo lokutholwa kwedijithali lweziteshi eziningi ezinamanani amasampula ahlukahlukene;19 - ikhompuyutha yomuntu siqu.
Ukwelashwa kwe-Ultrasonic kwenziwa kanje.I-laser isebenza kumodi esebenza mahhala;ngakho-ke ubude be-laser pulse ngu-\(\tau _L \sim 150~\upmu \text {s}\), ehlanganisa ubude besikhathi obungaba ngu-\(1.5~\upmu \text {s } \) ngakunye.Umumo wesikhashana we-laser pulse kanye ne-spectrum yawo iqukethe i-low-frequency of high-frequency,~7 umbhalo {MHz}\), njengoba kuboniswe kuMfanekiso 2.- Imvilophu yefrikhwensi ihlinzeka ngokushisisa nokuncibilika okulandelayo kanye nokuhwamuka kwezinto, kuyilapho ingxenye yemvamisa ephezulu ihlinzeka ngokudlidliza kwe-ultrasonic ngenxa yomphumela we-photoacoustic.I-waveform ye-ultrasonic pulse ekhiqizwa i-laser inqunywa ngokuyinhloko ukuma kwesikhathi kokuqina kwe-laser pulse.Isuka ku-\(7~\text {kHz}\) kuya ku-\ (2~\text {MHz}\), futhi imvamisa emaphakathi ithi \(~ 0.7~\text {MHz}\).Ama-Acoustic pulses ngenxa yomphumela we-photoacoustic aqoshwa kusetshenziswa ama-transducer e-broadband piezoelectric enziwe ngamafilimu e-polyvinylidene fluoride.Ama-waveform arekhodiwe abonisa ukuthi i-waveform ye-Fispectrum kufanele ibe yi-Fispectrum pulses. ejwayelekile ye-laser yemodi esebenza mahhala.
Ukusatshalaliswa kwesikhashana kwe-laser pulse intensity (a) kanye nesivinini somsindo (b) endaweni engemuva yesampula, i-spectra (ijika eliluhlaza okwesibhakabhaka) le-laser pulse eyodwa (c) kanye ne-ultrasound pulse (d) okulinganiselwa ngaphezu kwama-laser pulses angu-300 (ijika elibomvu) .
Singakwazi ukuhlukanisa ngokucacile izingxenye ze-low-frequency kanye ne-high-frequency yokwelashwa kwe-acoustic ehambisana nemvilophu ye-low-frequency ye-laser pulse kanye ne-high-frequency modulation, ngokulandelanayo.Ubude be-wavenge wamaza e-acoustic akhiqizwa imvilophu ye-laser pulse idlula \(40~\text {cm}\);ngakho-ke, umphumela oyinhloko wezingxenye ze-broadband high-frequency yesiginali ye-acoustic ku-microstructure kulindeleke.
Izinqubo zomzimba ku-SLM ziyinkimbinkimbi futhi zenzeka ngesikhathi esisodwa ezilinganisweni ezahlukene zendawo nezesikhashana.Ngakho-ke, izindlela ze-multi-scale zifaneleka kakhulu ukuhlaziywa kwethiyori ye-SLM.Amamodeli wezibalo kufanele ekuqaleni abe yi-multi-physical.I-mechanics kanye ne-thermophysics ye-multiphase medium "i-solid-liquid melt" isebenzisana nezici ze-inert yokulayisha igesi esebenzayo echazwe yi-smortable ye-inert yomthwalo wegesi.
Amazinga okushisisa nokupholisa afika \(10^6~\text {K}/\text {s}\) /\text{ ngenxa yokukhanya kwelaser okwenziwe kwasendaweni okunamandla afinyelela ku-\(10^{13}~\text {W} cm}^2\).
Umjikelezo wokuncibilika kokuncibilika uhlala phakathi kuka-1 kanye \(10~\text {ms}\), onikela ekuqiniseni ngokushesha indawo yokuncibilika phakathi nokupholisa.
Ukushisa okusheshayo kwendawo yesampula kubangela ukwakheka kokucindezeleka okuphezulu kwe-thermoelastic kungqimba olungaphezulu.Ingxenye eyanele (kufika ku-20%) ye-powder layer i-evaporated kakhulu63, okuholela kumthwalo owengeziwe wengcindezi ebusweni ekuphenduleni ukukhishwa kwe-laser.Ngenxa yalokho, ukucindezeleka okwenziwe kuhlanekezela ngokuphawulekayo ingxenye yejometri, ikakhulukazi eduze nezisekelo ze-laser ezikhiqizwayo ezisezingeni eliphezulu kanye nemiphumela ephansi ye-laser ekhiqizwayo. amagagasi obunzima asakaza ukusuka phezulu kuya ku-substrate.Ukuze kutholwe idatha yobuningi obunembile ekucindezelekeni kwendawo kanye nokusabalalisa kobunzima, ukulingiswa kwe-mesoscopic kwenkinga yokuguqulwa kwe-elastic okuhlanganiswe nokushisa nokudluliswa kwesisindo kwenziwa.
Izibalo ezilawulayo zemodeli zihlanganisa (1) izilinganiso zokudlulisa ukushisa okungazinzile lapho ukuqhutshwa kwe-thermal kuncike esimweni sesigaba (impuphu, incibilika, i-polycrystalline) nezinga lokushisa, (2) ukushintshashintsha kokushintshashintsha kokunwebeka ngemva kokukhishwa kwe-continuous ablation kanye ne-thermoelastic expansion equation.Inkinga yenani lomngcele inqunywa yizimo zokuhlola. x.I-mass flux ichazwa ngokusekelwe ekubalweni kokucindezela komhwamuko ogcwele wento ehwamukayo.Ubudlelwane be-elastoplastic stress-strain busetshenziswa lapho ingcindezi ye-thermoelastic ilingana nomehluko wezinga lokushisa.Ngamandla okuzisholo \(300~\text {W}\), imvamisa \(10^5~\\text {Hz~e-0}\(2) ikhefu {Hz} kanye ne-0} ububanzi be-beam obusebenzayo.
Umfanekiso 3 ubonisa imiphumela yokulingisa kwezinombolo yendawo encibilikisiwe kusetshenziswa imodeli yezibalo enkulukazi. Ububanzi bezoni yokuhlanganisa \(200~\upmu \text {m}\) (\(100~\upmu \text { m}\) irediyasi) kanye \(40~\upmu \umbhalo \umbhalo wemiphumela ebonisa ukujula okungu-1 K{0} okufana nombhalo wesikhathi ongu-1 {0}\) ngokujulile {0} ngombhalo wendawo. \) ngenxa yesici esiphezulu se-intermittent factor of the pulse module.Izilinganiso zokushisisa \(V_h\) nokupholisa \(V_c\) ziku-oda \(10^7\) kanye \(10^6~\text {K}/\text {s}\), ngokulandelana. Lawa manani avumelana kahle nomehluko wethu wangaphambilini we-mag(V__) we-mag(V_) nokuhlaziywa kwe-mag (V_) ye-mag(V_) ukushisisa ngokushesha kwesendlalelo esingaphezulu, lapho ukushintshwa okushisayo kwe-substrate kunganele ukususa ukushisa.Ngakho-ke, kokuthi \(t=26~\upmu \text {s}\) izinga lokushisa liphezulu lifinyelela phezulu \(4800~\text {K}\).Ukuhwamuka okunamandla kwento kungabangela ukuba indawo yesampula ibe ngaphansi kwengcindezi eyeqile futhi ixetshulwe.
Imiphumela yokulingisa yezinombolo yendawo encibilikayo ye-laser eyodwa yepulse annealing kupuleti lesampula elingu-316L. Isikhathi kusukela ekuqaleni kokushaya kwenhliziyo ukuya ekujuleni kwechibi elincibilikisiwe kufinyelela inani eliphakeme ngu-\(180~\upmu\text {s}\).I-isotherm\(T = T_L = 1723~.imelela uketshezi oluphakathi kwesigaba se-iso) ne-isotherm (i-isotherm) (i-isotherm) kanye ne-solid (K}) kuhambisana nokucindezeleka kwesivuno esibalwa njengomsebenzi wokushisa esigabeni esilandelayo.Ngakho-ke, esizindeni phakathi kwama-isolines amabili (i-isotherms\(T=T_L\) nama-isobars\(\sigma =\sigma _V(T)\)), isigaba esiqinile singaphansi kwemithwalo enamandla yemishini , okungase kuholele ekushintsheni kwe-microstructure.
Lo mphumela uchazwa ngokuqhubekayo kuMfanekiso 4a, lapho izinga lokucindezela endaweni encibilikisiwe lihlelwa njengomsebenzi wesikhathi nebanga ukusuka endaweni.Okokuqala, ukuziphatha kokucindezela kuhlobene nokuguqulwa kwe-laser pulse intensity echazwe kuMfanekiso 2 ngenhla.Ingcindezi enkulu \umbhalo{s}\) cishe \(10~\\text {MPa}~6d,c\) yabonwa indawo {MPa}cond\)=indawo eyabonwayo {MPa}cond\) = i-fluid yasendaweni ibonwe). ukucindezela endaweni yokulawula kunezici ezifanayo ze-oscillation njengemvamisa ye-\(500~\text {kHz}\).Lokhu kusho ukuthi amagagasi okucindezela kwe-ultrasonic akhiqizwa phezulu bese asakaza ku-substrate.
Izici ezibaliwe ze-deformation zone eduze nendawo yokuncibilika ziboniswa ku-Fig. 4b. Ukukhishwa kwe-laser nokucindezeleka kwe-thermoelastic kukhiqiza amagagasi okuguquguquka okunwebekayo asakazeka ku-substrate.Njengoba kungabonwa emfanekisweni, kunezigaba ezimbili zokukhiqiza ukucindezeleka.Ngesikhathi sokuqala kwesigaba \(t <40~\upmu \MP{ssss)\umbhalo we-MP (8) ukukhuphuka okufana nombhalo {s}\}, ukukhuphuka kombhalo we-MP (8) kuya ekucindezelweni okungaphezulu.Lokhu kucindezeleka kwenzeka ngenxa yokukhishwa kwe-laser, futhi akukho ukucindezeleka kwe-thermoelastic okubonwa ezindaweni zokulawula ngenxa yokuthi indawo yokuqala ethinteke ukushisa yayincane kakhulu.Lapho ukushisa kukhishwa ku-substrate, indawo yokulawula ikhiqiza ukucindezeleka okuphezulu kwe-thermoelastic ngaphezulu \(40~\text {MPa}\).
Amazinga okucindezeleka ashintshiwe atholiwe anomthelela obalulekile kusixhumi esibonakalayo esiqinile-oketshezi futhi angase abe indlela yokulawula elawula indlela yokuqinisa.Usayizi wendawo yokuguquguquka bukhulu ngokuphindwe izikhathi ezingu-2 kuya kwezingu-3 kunaleyo yendawo yokuncibilika.Njengoba kuboniswe kuMfanekiso 3, indawo ye-isotherm encibilikayo kanye nezinga lokucindezeleka elilingana ne-stressed i-stressed ezindaweni ezine-dierrased ye-high kunikeza i-laser yomthwalo we-mechanical ephumelelayo uma kuqhathaniswa ne-laser ye-mechanical. 300 kanye nokuthi \(800~\upmu \text {m}\) kuye ngesikhathi esisheshayo.
Ngakho-ke, ukuguqulwa okuyinkimbinkimbi kwe-pulsed laser annealing kuholela kumphumela we-ultrasonic.Indlela yokukhetha i-microstructure ihlukile uma iqhathaniswa ne-SLM ngaphandle kokulayisha kwe-ultrasonic.Izifunda eziguquguqukayo eziguquguqukayo ziholela emijikelezweni yezikhathi zokucindezela nokwelula esigabeni esiqinile.Ngakho-ke, ukwakheka kwemingcele emisha yokusanhlamvu kanye nemingcele ye-subgrain etholakalayo ingakwazi ukuhlinzeka ngendlela engenzeka ngayo, ngakho-ke izakhiwo ezitholakala ngezansi zingakwazi ukuhlinzeka. klama i-pulse modulation-induced ultrasound-driven SLM prototype.Kulokhu, i-piezoelectric inductor 26 esetshenziswa kwenye indawo ingafakwa ngaphandle.
(a) Ingcindezi njengomsebenzi wesikhathi, obalwa kumabanga ahlukene ukusuka endaweni engu-0, 20 kanye \(40~\upmu \text {m}\) eduze kwe-eksisi yokulinganisa.(b) Ingcindezi ka-Von Mises encike esikhathini ebalwa nge-matrix eqinile ebangeni elingu-70, 120 kanye \(170~\\) nombhalo wesampula {m}
Ukuhlolwa kwenziwa ezingcwecweni zensimbi engagqwali ye-AISI 321H ezinobukhulu \(20\times 20\times 5~\text {mm}\).Ngemuva kwe-laser pulse ngayinye, ipuleti liyanyakaza \(50~\upmu \text {m}\), futhi ukhalo lwe-laser endaweni okuqondiswe kuyo lucishe lube \(100~pm ukuya ku-track} efanayo). bangela ukuguqulwa kwezinto ezicutshungulwayo ukuze kulungiswe okusanhlamvu.Kuzo zonke izimo, indawo encibilikisiwe yayiyi-sonicated, kuye ngokuthi ingxenye ye-oscillatory yemisebe ye-laser.Lokhu kuphumela ekunciphiseni okungaphezu kwama-5 endaweni yokusanhlamvu okulinganiselwe.Umfanekiso we-5 ubonisa ukuthi i-microstructure yesifunda esincibilikisiwe se-laser sishintsha kanjani ngenani lemijikelezo yokuphindaphinda elandelayo (i-remelting cycle).
Izingxenye ezingezansi (a,d,g,j) kanye no-(b,e,h,k) – i-microstructure yezifunda ezincibilikisiwe nge-laser, iziqeshana (c,f,i,l) – ukusatshalaliswa kwendawo okusanhlamvu okunemibala.Ukufiphaza kumelela izinhlayiya ezisetshenziselwa ukubala i-histogram.Imibala ihambisana nezifunda zokusanhlamvu (bona ibha yombala phezulu kwe-histogram. Izingxenye ezingezansi (ac) zihambisana nensimbi engagqwali engalashwanga, nama-subplots (df), (gi), (jl) ahambisana no-1, 3 kanye no-5 remelts.
Njengoba i-laser pulse energy ingashintshi phakathi kokudlula okulandelayo, ukujula kwendawo encibilikisiwe kuyafana.Ngakho-ke, isiteshi esilandelayo "sihlanganisa" ngokuphelele esedlule.Nokho, i-histogram ibonisa ukuthi indawo yokusanhlamvu ephakathi nendawo iyancipha ngenani elikhulayo lokudlula.Lokhu kungase kubonise ukuthi i-laser isebenza ku-substrate esikhundleni sokuncibilika.
Ukucolisiswa okusanhlamvu kungase kubangelwe ukupholisa ngokushesha kwechibi elincibilikisiwe65.Enye isethi yokuhlola yenziwa lapho okungaphezulu kwamapuleti ensimbi engagqwali (321H kanye no-316L) kuvezwe emisebeni ye-laser yamaza eqhubekayo emkhathini (Fig. 6) kanye ne-vacuum (Fig. 7).Isilinganiso samandla e-laser (3000 W) kanye nemiphumela yokuhlola evala ngokulinganayo ukujula kwe-laser (3000 W kanye nokujula kwe-molten) ukujula ngokulinganayo I-Nd: I-LAG ye-LAG kumodi esebenza mahhala.Nokho, isakhiwo esijwayelekile sekholomu sabonwa.
Isakhiwo esincane sesifunda esincibilikisiwe nge-laser se-laser yegagasi eqhubekayo (amandla angashintshi angu-300 W, isivinini sokuskena esingu-200 mm/s, i-AISI 321H yensimbi engagqwali).
(a) I-Microstructure kanye (b) nesithombe se-electron backscatter diffraction sendawo yokuncibilika kwe-laser ye-vacuum wave eqhubekayo (amandla aqhubekayo angu-100 W, isivinini sokuskena esingu-200 mm/s, AISI 316L insimbi engagqwali) \ (\ sim 2~\text {mbar }\).
Ngakho-ke, kuboniswa ngokucacile ukuthi ukuguquguquka okuyinkimbinkimbi kwe-laser pulse intensity kunomthelela omkhulu ku-microstructure. i-ultrasound ezintweni ezihlukahlukene ezihlanganisa i-Ti-6Al-4V ingxubevange 26 kanye nensimbi engagqwali 34 umphumela.Indlela engenzeka icatshangwa kanje.I-ultrasound enamandla ingabangela i-acoustic cavitation, njengoba kuboniswe ku-ultrafast in situ synchrotron imaging ye-X-ray.Ukuwohloka kwe-cavitation yamabhamuza ~0, okuthi i-MP ifinyelele ama-bubbles angaphambili ngokushintshana kwawo{0] }\)69.Amagagasi anjalo athusayo angase abe namandla ngokwanele ukuze akhuthaze ukwakheka kwe-nuclei yesigaba esiqinile esinosayizi obalulekile oketshezini oluyinqwaba, aphazamise ukwakheka kwekholomu okusanhlamvu okujwayelekile kokukhiqiza okungeziwe kwesendlalelo nesendlalelo.
Lapha, siphakamisa enye indlela ebhekele ukuguqulwa kwesakhiwo nge-sonication ejulile.Impahla ngemva nje kokuqiniswa isezingeni eliphezulu lokushisa eduze nendawo yokuncibilika futhi ine-stress yesivuno esiphansi kakhulu.Amagagasi amakhulu e-ultrasonic angabangela ukugeleza kwepulasitiki ukuze kushintshe ukwakheka kokusanhlamvu kwezinto ezishisayo ezisanda kuqiniswa.Nokho, idatha yokuhlola enokwethenjelwa ekuncikeni kwezinga lokushisa kwe-ieldstresses of yield {~(T 1 Figureg) iyatholakala ku-(T 1 Figureg). 8) .Ngakho-ke, ukuhlola i-hypothesis, senza ukulingisa kwe-molecular dynamics (MD) yokwakheka kwe-Fe-Cr-Ni efana ne-AISI 316 L yensimbi ukuze sihlole ukuziphatha kokucindezeleka kwesivuno eduze nendawo yokuncibilika.Ukubala ukucindezeleka kwesivuno, sasebenzisa inqubo yokuphumula yokucindezeleka ye-MD echazwe ku-70, 71, i-interculations ye-71, i-71, i-Ambe37 ye-interculations. I-tomic Model (EAM) kusukela ekufanisweni kwe-74.MD kwenziwa kusetshenziswa amakhodi e-LAMMPS 75,76.Imininingwane yokulingisa kwe-MD izoshicilelwa kwenye indawo.Imiphumela yokubala ye-MD yokucindezeleka kwesivuno njengomsebenzi wezinga lokushisa iboniswa ku-Fig. 8 kanye nedatha yokuhlola etholakalayo nokunye ukuhlola77,78,79,818,8.
Ukucindezeleka kwesivuno se-AISI grade 316 insimbi engagqwali ye-austenitic kanye nokwakheka kwemodeli ngokumelene nezinga lokushisa lokulingiswa kwe-MD. Izilinganiso zokuhlola ezivela ezithenjwa: (a) 77, (b) 78, (c) 79, (d) 80, (e) 81.bhekisela. .Imiphumela yokulingisa ye-MD yezinga elikhulu kulolu cwaningo ichazwa ngokuthi \(\vartriangleleft\) yekristalu eyodwa engenamkhawulo engenasici kanye \(\vartriangleright\) yezinhlamvu ezinomkhawulo kucatshangelwa usayizi wokusanhlamvu omaphakathi nge-Hall-Petch relation Dimensions\(d = 50~\upmu \text {m}\).
Kungabonakala ukuthi \(T>1500~\text {K}\) ukucindezeleka kwesivuno kwehla ngezansi \(40~\text {MPa}\). Ngakolunye uhlangothi, izilinganiso zibikezela ukuthi i-laser-generated ultrasonic amplitude idlula \(40~\text {MPa}\) (bona Fig. 4b), eyanele ukugeleza okuqinile kupulasitiki oshisayo.
Ukwakhiwa kwe-microstructure ye-12Cr18Ni10Ti (AISI 321H) i-austenitic stainless steel phakathi ne-SLM kwaphenywa ngokuhlolwa kusetshenziswa umthombo we-laser we-pulsed intensity-modulated.
Ukwehliswa kosayizi wokusanhlamvu endaweni yokuncibilika kwe-laser kutholwe ngenxa yokuncibilika kwe-laser okuqhubekayo ngemva kokudlula oku-1, 3 noma oku-5.
Ukumodela kwe-Macroscopic kubonisa ukuthi usayizi olinganiselwe wesifunda lapho ukuwohloka kwe-ultrasonic kungase kuthinte kahle ingaphambili lokuqinisa kufika \(1~\text {mm}\).
Imodeli ye-MD ye-microscopic ibonisa ukuthi amandla okukhiqiza e-AISI 316 austenitic stainless steel ancipha kakhulu ukuze abe \(40~\text {MPa}\) eduze nendawo yokuncibilika.
Imiphumela etholiwe iphakamisa indlela yokulawula i-microstructure yezinto kusetshenziswa ukucutshungulwa kwe-laser okuyinkimbinkimbi futhi ingase isebenze njengesisekelo sokudala ukuguqulwa okusha kwenqubo ye-SLM eshayekile.
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