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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. amanani, kanye nobunzima bomjikelezo wokushisa ezintweni ezincibilikayo nezincibilikisayo11, okuholela ekukhuleni kokusanhlamvu kwe-epitaxial kanye ne-porosity ephawulekayo12,13.Imiphumela ibonisa ukuthi , kuyadingeka ukulawula ama-gradients ashisayo, amazinga okupholisa, kanye nokwakheka kwe-alloy, noma ukusebenzisa ukushaqeka okungeziwe ngokomzimba ngezinkambu zangaphandle zezakhiwo ezihlukahlukene (isb, i-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 efiselekayo.Uma umthamo wesigaba soketshezi uncane, isimo sishintsha kakhulu.Kulokhu, inkambu yangaphandle ithinta kakhulu inqubo yokuqinisa. 0,21,22,23,24,25,26,27, arc stirring28 kanye ne-oscillation29, pulsed plasma arcs30,31 nezinye izindlela32 .Namathisela ku-substrate usebenzisa umthombo wangaphandle we-ultrasound we-high-intensity ultrasound (ku-20 kHz).I-ultrasound-induced composition is i-ultrasound-induced the-tribution to the-recented the-reach to-rexed totribuient to-substrate ukuthuthukiswa kwe-ultrasound 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.
Umthelela oshisayo wesigameko semisebe ye-laser phakathi nendawo uyisisekelo cishe sawo wonke amasu e-laser 39, 40 okucubungula impahla, njengokusika41, ukushisela, ukuqina, ukubhoboza42, ukuhlanzwa kwendawo, ingxubevange, ukucwebezelisa komhlaba43, njll.
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 endaweni engemuva yesampula (b), i-spectra ye-laser pulse (c) kanye ne-ultrasonic pulse (d) okulinganiselwa ngaphezu kwama-laser pulse angu-300 (ijika elibomvu) le-laser eyodwa (ijika eliluhlaza okwesibhakabhaka) .
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) nezithombe ze-electron backscatter diffraction zesifunda esincibilikisiwe nge-laser endaweni engenalutho enelaser yegagasi eqhubekayo (amandla angashintshi angu-100 W, isivinini sokuskena esingu-200 mm/s, i-AISI 316L yensimbi 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 enamandla.Ngokushesha nje ngemva kokuqina, impahla isezingeni lokushisa eliphezulu eduze nendawo yokuncibilika futhi inengcindezi yesivuno ephansi kakhulu.Amaza anamandla e-ultrasonic angabangela ukugeleza kwepulasitiki ukuguqula ukwakheka kokusanhlamvu kwezinto ezishisayo, eziqinile nje.Kodwa-ke, idatha yokuhlola enokwethenjelwa ekuncikeni kwe-stress 1 iyatholakala ku-stresse1\~K iyatholakala (i-T 1. ) (bheka Umfanekiso 8) .Ngakho-ke, ukuze sihlole le nkolelo-mbono, senza ukulingisa kwe-molecular dynamics (MD) yokwakheka kwe-Fe-Cr-Ni efana nensimbi ye-AISI 316 L ukuze sihlole ukuziphatha kokucindezeleka kwesivuno eduze nendawo yokuncibilika.Ukuze ubale ukucindezeleka kwesivuno, sasebenzisa inqubo yokuphumula yokucindezeleka ye-MD shear eningiliziwe ku-7,30,7,30, 7,30, 7. wasebenzisa i-Embedded Atomic Model (EAM) kusukela ku-74.MD ukulingisa kwenziwa kusetshenziswa amakhodi e-LAMMPS 75,76.Imininingwane yokufanisa kwe-MD izoshicilelwa kwenye indawo.Imiphumela yokubala ye-MD yokucindezeleka kwesivuno njengomsebenzi wokushisa iboniswa ku-Fig. 8 kanye nedatha yokuhlola etholakalayo nokunye ukuhlola17,828,828.
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 kwe-MD yezinga elikhulu kulolu cwaningo ichazwa njengokuthi \(\vartriangleleft\) yecrystal eyodwa engapheli engenasici kanye \(\vatriangleright\) yezinhlamvu ezinomkhawulo kucatshangelwa usayizi wokusanhlamvu omaphakathi nge-Hall-Petch Relation Dimensions\(d = 50~\upmu \umbhalo {m}\).
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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