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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 kanye nezinye9,10, Izingxenye zingase zibe nesici.Lokhu kubangelwa ikakhulukazi ukuncibilika kwe-molten ephezulu okuhambisana nenqubo ye-molten ephezulu ama-gradients, amazinga okupholisa aphezulu, kanye nobunzima bomjikelezo wokushisa ezintweni ezincibilikayo nezincibilikisayo11, okuholela ekukhuleni kokusanhlamvu kwe-epitaxial kanye ne-porosity12,13 ebalulekile. 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.
Ukushicilelwa okuningi kuphathelene nomthelela wokwelashwa kokudlidliza kunqubo yokuqinisa ezinqubweni zokusakaza ezivamile14,15.Nokho, ukusebenzisa inkambu yangaphandle ekuncibilikeni kwenqwaba akukhiqizi i-microstructure yezinto efiselekayo.Uma umthamo wesigaba se-liquid ulincane, isimo sishintsha kakhulu.Kulokhu, inkambu yangaphandle ithinta kakhulu inqubo yokuqinisa.I-electromagnetic effect ibhekwe njengemiphumela ye-electromagnetic in the effect. amasimu16,17,18,19,20,21,22,23,24,25,26,27, arc stirring28 and oscillation29, pulsed plasma arcs30,31 nezinye izindlela32 .Namathisela ku-substrate usebenzisa i-high-intensity ultrasound source yangaphandle (at ultrasound refried source) i-subcooling zone eyandisiwe ngenxa yokuncipha kwezinga lokushisa kanye nokuthuthukiswa kwe-ultrasound ukuze kukhiqizwe amakristalu amasha nge-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 ebamba ukukhanya kuphumela ekukhiqizeni amagagasi e-ultrasonic, ashintsha i-microstructure ye-microstructure ye-radiation ye-SLM ehlanganisiwe ye-sLM ekhona kalula. Ukuhlola kulo msebenzi kwenziwa ezingcwecweni zensimbi engagqwali okuvele kwazo kuvezwe emisebeni ye-laser eshintshiwe ngamandla.Ngakho-ke, ngokobuchwepheshe, ukwelashwa kwe-laser kuyenziwa.Kodwa-ke, uma ukwelapha okunjalo nge-laser kwenziwa phezu kwesendlalelo ngasinye, ngesikhathi sokwakhiwa kwesendlalelo ngesendlalelo, imiphumela kuyo yonke ivolumu noma ezingxenyeni ezikhethiwe zevolumu ziyafinyelelwa.Ngamanye amazwi, ungqimba olwakhiwe nge-laser lwenziwa ungqimba ngalunye lwe-laser lwenziwa phezu kwesendlalelo ngasinye, ngesikhathi sokwakhiwa kwe-layer-by-layer, imiphumela kuyo yonke ivolumu noma ezingxenyeni ezikhethiwe zevolumu iyafinyelelwa. "Ukwelashwa kwevolumu ye-laser".
Nakuba ku-ultrasonic uphondo olusekelwe ku-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. ingxenye.Ngakho-ke, ukucindezeleka kwe-acoustic kuseduze ne-zero futhi isivinini sezinhlayiyana sine-amplitude enkulu phezu kwayo yonke indawo ephezulu yengxenye.Ukucindezela komsindo ngaphakathi kwechibi elincibilikisiwe lonke awukwazi ukudlula u-0.1% wokucindezela okukhulu okukhiqizwa ikhanda lokushisela, ngenxa yokuthi ubude be-wavenge bamagagasi e-ultrasonic ne-frequency ye-20 kHz ku-20 kHz ku-stainless steel {0m}~m kanye nombhalo we-stainless 0m (~m). ngaphansi kuka-\(\sim 0.3~\text {mm}\).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, ukuhlanza indawo engaphezulu, ingxubevange, ukucwebezeliswa kwendawo43, njll. ama-monographs44,45,46.
Kufanele kuqashelwe ukuthi noma isiphi isenzo esingamile endaweni ephakathi, okuhlanganisa isenzo sokubambelela endaweni emuncayo, siphumela ekuvusweni kwamagagasi e-acoustic kuwo ngokusebenza kahle okungaphezulu noma okuncane.Ekuqaleni, ukugxila okuyinhloko kwakusekuvusweni kwe-laser kwamagagasi oketshezi kanye nezindlela ezihlukahlukene zokuvusa ukushisa okushisayo komsindo (ukunwetshwa kokushisa, ukuhwamuka, ukuguqulwa kwevolumu, ukushintshwa kwevolumu ye-4, njll. 49.Ama-monographs amaningi50, 51, 52 ahlinzeka ngohlaziyo lwethiyori lwale 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.
Ukuhlola kwenziwe 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 kumodi egijima mahhala (ubude be-pulse \(\tau _L \sim 150~\upmu \uchungechunge lwe-neutral lusetshenziswe nge-laser edlulisiwe) isetshenziswe uchungechunge lwe-laser edlulisiwe {s}) izihlungi kanye nesistimu yepuleti le-beam splitter.Ngokuya ngenhlanganisela yezihlungi zokuminyana ezimaphakathi, amandla okushaya kwenhliziyo kokuqondisiwe ayahluka ukusuka kokuthi \(E_L \sim 20~\text {mJ}\) ukuya \(E_L \sim 100~\text {mJ}\) .I-laser beam evela kusihlukanisi se-beam inikezwa idatha ye-caloric ye-simuriquisi eyodwa yedatha yesithombe esifana nesesilinganisi se-calories ephakelwa i-simuriquisimeter yesithombe esisodwa. (ama-photodiodes anesikhathi eside sokuphendula esidlula \(1~\text {ms}\)) asetshenziselwa ukunquma isigameko esiya futhi sibonakale kusukela ekuqondisweni, kanye namamitha kagesi amabili (ama-photodiodes anezikhathi ezimfushane zokuphendula\(<10~\text {ns}\)) ukuze kunqunywe isigameko namandla okubona abonisiwe.Ama-calories namamitha kagesi alinganiswa ukuze anikeze amanani kusetshenziswa i-unitmoteor detector I-XLP12-3S-H2-D0 nesibuko se-dielectric esifakwe endaweni yesampula. Gxilisa i-beam kukho okuqondiwe usebenzisa ilensi (I-Antireflection coating kokuthi \(1.06 \upmu \umbhalo {m}\), ubude befocal \(160~\text {mm}\)) kanye nokhalo lwe-beam endaweni eqondiwe engu-1\\up \\ up 60m\\\ up).
Umdwebo wohlelo olusebenzayo lokusethwa kokuhlola: 1-laser; 2 - i-laser; 3-i-neutral density filter; 4—i-photodiode evumelanisiwe; 5 - isihlukanisi se-beam; 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 cishe cishe \(1.5~\upmu \text {s } \) ngayinye.Ukuma kwesikhashana kwe-laser pulse kanye ne-spectrum yayo kuhlanganisa i-low-frequency ye-moduquency nemvilophu ye-high-frequency \(0.7~\text {MHz}\), njengoba kuboniswe kuMfanekiso 2.- Imvilophu yefrikhwensi ihlinzeka ngokushisisa nokuncibilika okulandelayo kanye nokuhwamuka kwempahla, kuyilapho ingxenye yefrikhwensi ephezulu ihlinzeka ngokudlidliza kwe-ultrasonic ngenxa yomphumela we-photoacoustic.I-waveform ye-ultrasonic pulse ekhiqizwa i-laser inqunywa ngokuyinhloko umumo wesikhathi we-laser pulse inten. Isuka kokuthi \(7~\text {kHz}\) kuya ku-\ (2~\text {MHz}\), futhi imvamisa emaphakathi ithi \(~ 0.7~\text {MHz}\).Ama-Acoustic pulses ngenxa yomphumela we-photoacoustic aqoshwe kusetshenziswa ama-transducer e-broadband piezoelectric enziwe ngamafilimu e-polyvinylidene fluoride.I-waveform erekhodiwe kufanele iboniswe ukuthi i-waveform ye-Fispectre kufanele ibe yi-Fispectrum eqoshiwe. i-laser pulses ijwayelekile ye-laser yemodi egijima 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 adlula \(40~\text {cm}\); 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 ezibalo kufanele ekuqaleni abe yi-multi-physical.I-mechanics kanye ne-thermophysics ye-multiphase medium "i-solid-liquid melt" isebenzisana nezici ze-inert yomthwalo wegesi esebenzayo echazwe njengegesi ye-inert echazwe ngendlela esebenzayo yokulayisha igesi ye-SM. uyalandela.
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%) yongqimba lwempushana ihwamuka kakhulu63, okuphumela kumthwalo owengeziwe wengcindezi ebusweni ekuphenduleni ukukhishwa kwe-laser.Ngenxa yalokho, ukucindezeleka okubangelwayo kuhlanekezela ngokuphawulekayo ingxenye yejometri, ikakhulukazi eduze nezisekelo ze-laser ezisezingeni eliphezulu kanye nemiphumela emincane ye-laser yokushisa. Ukukhiqizwa kwamagagasi obunzima be-ultrasonic asakaza ukusuka phezulu kuya ku-substrate.Ukuze uthole idatha enembile yobuningi ekucindezelekeni kwendawo kanye nokusabalalisa kobunzima, ukumbumbuluzwa kwe-mesoscopic yenkinga yokuguqulwa kwe-elastic ehlanganiswe nokushisa nokudluliswa kwenqwaba kwenziwa.
Izibalo ezibusayo zemodeli zihlanganisa (1) izilinganiso zokudlulisa ukushisa okungazinzile lapho ukuqhutshwa kwe-thermal kuncike esimweni sesigaba (impushana, incibilika, i-polycrystalline) nezinga lokushisa, (2) ukuguquka kokushintshashintsha kokunwebeka ngemva kokukhishwa kwe-continuous ablation kanye ne-thermoelastic expansion equation.Inkinga yenani lomngcele inqunywa yizimo zokuhlola. kanye ne-evaporative flux.I-mass flux ichazwa ngokusekelwe ekubalweni kokucindezela komhwamuko ogcwele wento ehwamukayo.Ubudlelwane obusebenzayo be-elastoplastic stress-strain busetshenziswa lapho ingcindezi ye-thermoelastic ilingana nomehluko wezinga lokushisa.Ngamandla okuzisholo \(300~\text {W}\), imvamisa \(10^5~\text) 10^5~\text {0}futhi intermit {0} \(200~\upmu \umbhalo {m}\ ) wobubanzi obusebenzayo begxolo.
Umfanekiso 3 ubonisa imiphumela yokulingisa kwezinombolo yendawo encibilikisiwe kusetshenziswa imodeli yezibalo enkulukazi. Ububanzi bendawo yokuhlanganisa \(200~\upmu \text {m}\) (\(100~\upmu \text { m}\) irediyasi) kanye \(40~\upmu \umbhalo \umbhalo {m}\) ubonisa ukujula kobude besikhathi obubonisa ukuthi izinga lokushisa elilinganayo {m}\) libonisa ukujula kwasendaweni. \(100~\text {K}\) ngenxa yesici esiphezulu esikhawulayo sokushintshwa kwenhliziyo. Izilinganiso zokushisisa \(V_h\) nokupholisa \(V_c\) ziku-oda \(10^7\) kanye \(10^6~\text {K}/\text {s}\), ngokulandelanayo.Lawa manani ahambisana nomehluko omkhulu ngokwedlulele ngokwendlela yethu yangaphambilini. \(V_h\) kanye \(V_c\) kuholela ekushiseni okushesha kakhulu kwesendlalelo esingaphezulu, lapho ukushintshwa okushisayo kuya ku-substrate kunganele ukususa ukushisa. Ngakho-ke, \(t=26~\upmu \text {s}\) izinga lokushisa liphezulu kakhulu \(4800~\text {K}\).
Imiphumela yokulingisa yezinombolo yendawo encibilikayo ye-laser eyodwa yepulse annealing kupuleti lesampula elingu-316L. Isikhathi kusukela ekuqaleni kokushaya kwenhliziyo kuye ekujuleni kwechibi elincibilikisiwe kufinyelela inani eliphakeme ngu-\(180~\upmu\text {s}\).I-isotherm\(T = T_L = 1723~.imelela uketshezi oluphakathi kwesigaba) nombhalo oqinile {K} (imigqa ephuzi) ihambisana 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 ku-Figure 4a, lapho izinga lokucindezela endaweni encibilikisiwe lihlelwe njengomsebenzi wesikhathi nebanga ukusuka endaweni.Okokuqala, ukuziphatha kwengcindezi kuhlobene nokuguquguquka kwe-laser pulse intensity echazwe kuMfanekiso 2 ngenhla.Ingcindezi enkulu \umbhalo{s}\) cishe \(10~\\text {MPa}~6,\) ibonwe {MPa}~6,\) = ibonwe). ukuguquguquka kokucindezela kwendawo endaweni yokulawula kunezici ezifanayo ze-oscillation njengemvamisa ye-\(500~\text {kHz}\).Lokhu kusho ukuthi amagagasi okucindezela kwe-ultrasonic akhiqizwa phezulu abese esakaza ku-substrate.
Izici ezibaliwe zendawo yokuguqulwa eduze kwendawo 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. Phakathi nesigaba sokuqala \ (t <40~\upmu \ MPs stress {s}\}), umbhalo we-MP (8\}) ukuguqulwa okufana nokucindezela kwendawo.Lokhu kucindezeleka kwenzeka ngenxa ye-laser ablation, futhi akukho ukucindezeleka kwe-thermoelastic okubonwe ezindaweni zokulawula ngoba indawo yokuqala ethinteke ukushisa yayincane kakhulu.Lapho ukushisa kukhishwa ku-substrate, indawo yokulawula ikhiqiza ukucindezeleka okuphezulu kwe-thermoelastic ngenhla \(40~\text {MPa}\).
Amazinga okucindezeleka ashintshiwe atholiwe anomthelela obalulekile kusixhumi esibonakalayo esiqinile-oketshezi futhi angase abe indlela yokulawula elawula indlela yokuqinisa.Ubukhulu bendawo yokuguqula bukhulu ngokuphindwe izikhathi ezingu-2 kuya kwezingu-3 kunaleyo yendawo yokuncibilika.Njengoba kuboniswe kuMfanekiso 3, indawo ye-isotherm encibilikayo kanye nezinga lokucindezeleka elilingana nokucindezeleka kwesivuno ezindaweni ezinomthwalo we-pulse ophakeme uhlinzeka nge-laser yomshini wendawo lapho kuqhathaniswa khona. ububanzi obusebenzayo phakathi kuka-300 kanye no-\(800~\upmu \text {m}\) 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 yesikhathi sokucindezela nokwelula esigabeni esiqinile.Ngakho-ke, ukwakheka kwemingcele emisha yokusanhlamvu kanye nemingcele ye-subgrain etholakalayo ingashintshwa njenge-microstrucally. iziphetho zinikeza ithuba lokuklama 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 eqondiwe cishe \(100~pm five to beam paque are about \(100~pm five to beam paque are). ngokuhambisana nethrekhi efanayo ukuze kubangele ukuncibilika kwezinto ezicutshungulwayo ukuze kulungiswe okusanhlamvu.Kuzo zonke izimo, indawo encibilikisiwe yayiyi-sonicated, kuye ngokuthi ingxenye ye-oscillatory ye-radiation ye-laser.Lokhu kuphumela ekunciphiseni okungaphezu kwama-5 endaweni yesilinganiso sokusanhlamvu.Umfanekiso we-5 ubonisa ukuthi i-microstructure yesifunda esincibilikisiwe se-laser sishintsha kanjani ngenombolo ye-remelting elandelayo (i-pamelting).
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, 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 ne-molten pool ukujula) ngokulinganayo sivala ukujula kwe-laser (3000 W) imiphumela yokuhlola ye-laser ye-Nd:YAG kumodi esebenza mahhala.Nokho, isakhiwo sekholomu esijwayelekile sabonwa.
I-Microstructure yesifunda esincibilikisiwe nge-laser ye-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. ukuhlinzeka nge-high-intensity ultrasound ezintweni ezihlukahlukene ezihlanganisa i-Ti-6Al-4V ingxubevange engu-26 nensimbi engagqwali 34 umphumela.Indlela engenzeka icatshangwa kanje.I-ultrasound enamandla ingabangela i-acoustic cavitation, njengoba kuboniswe ku-ultrafast in situ synchrotron X-ray imaging.Ukuwohloka kwe-cavitation yezinto ezicindezelwayo zenza i-bubble yangaphambili ibangele ukushaqeka kwe-bubble. \(100~\text {MPa}\)69.Amaza okuthuka anjalo angase abe namandla ngokwanele ukuze akhuthaze ukwakheka kwe-nuclei yesigaba esiqinile esinosayizi obalulekile kuketshezi oluyinqwaba, aphazamise ukwakheka kwekholomu okusanhlamvu okujwayelekile kokukhiqiza okungeziwe kwesendlalelo ngesendlalelo.
Lapha, siphakamisa enye indlela ebhekele ukuguqulwa kwesakhiwo nge-sonication ejulile. Ngokushesha ngemva kokuqina, impahla isezingeni eliphezulu lokushisa eduze nendawo yokuncibilika futhi ine-stress yesivuno esiphansi kakhulu. Amagagasi amakhulu e-ultrasonic angabangela ukugeleza kwepulasitiki ukuguqula isakhiwo sokusanhlamvu sezinto ezishisayo, eziqinile nje. 1150 ~\text {K}\) (bheka Umfanekiso 8).Ngakho-ke, ukuze sihlole le nkolelo-mbono, senze ukulingisa kwe-molecular dynamics (MD) yokwakheka kwe-Fe-Cr-Ni efana nensimbi ye-AISI 316 L ukuze sihlole ukuziphatha kokucindezeleka kwesivuno eduze kwendawo yokuncibilika.Ukubala ukucindezeleka kwesivuno, sasebenzisa ukucindezeleka 17, sisebenzisa i-MD 7, i-stress 17, i-MD, i-7, i-7. 73.Ekubalweni kokusebenzisana kwe-interatomic, sisebenzise i-Embedded Atomic 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 ndawonye nenye idatha yokuhlola etholakalayo 8 kanye nenye idatha yokuhlola etholakalayo. izilinganiso77,78,79,80,81,82.
Ukucindezelwa kwesivuno se-AISI grade 316 insimbi engagqwali ye-austenitic kanye nokwakheka kwemodeli ngokumelene nezinga lokushisa lokulingiswa kwe-MD. Izilinganiso zokuhlola ezivela kumareferensi: (a) 77, (b) 78, (c) 79, (d) 80, (e) 81.bhekisela. ukukhiqizwa okungeziwe okusizwa nge-laser.Imiphumela yokulingisa kwe-MD yezinga elikhulu kulolu cwaningo ichazwa njengokuthi \(\vartriangleleft\) yekristalu eyodwa engapheli engenasici kanye \(\vatriangleright\) yezinhlamvu ezinomkhawulo kucatshangelwa usayizi wokusanhlamvu omaphakathi ngokuhlobana kwe-Hall-Petch Dimensions\(d\umbhalo \(d\up 50m).
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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