Siyabonga ngokuvakashela i-Nature.com.Inguqulo yesiphequluli oyisebenzisayo inokusekelwa okulinganiselwe kwe-CSS.Ukuze uthole ulwazi olungcono kakhulu, sincoma ukuthi usebenzise isiphequluli esibuyekeziwe (noma uvale imodi yokuhambisana ku-Internet Explorer).Okwamanje, ukuze siqinisekise ukwesekwa okuqhubekayo, sizobonisa isayithi ngaphandle kwezitayela ne-JavaScript.
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 ekuncibilikeni nasekucibilikeni kwezinto ezingu-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.
Ukushicilela okuningi kuphathelene nomphumela wokwelashwa kokudlidliza kwinqubo yokuqinisa ezinqubweni zokusakaza ezivamile14,15.Nokho, ukusebenzisa inkambu yangaphandle ekuncibilikeni kwenqwaba akukhiqizi i-microstructure yezinto oyifunayo.Uma umthamo wesigaba se-liquid mncane, isimo sishintsha kakhulu.Kulokhu, inkambu yangaphandle ithinta kakhulu inqubo yokuqinisa umsindo oqinile. fields16,17,18,19,20,21,22,23,24,25,26,27, arc stirring28 and oscillation29, electromagnetic effects during pulsed plasma arcs30,31 and other ways32 ziye zacatshangelwa .Namathisela ku-substrate usebenzisa i-ultrasound source high-incentity2 i-ultrasound high-intens). ukucwengisiswa kubangelwa ukukhuphuka kwendawo yokupholisa kancane ngenxa yokuncipha kwezinga lokushisa kanye nokuthuthukiswa kwe-ultrasound ukuze kukhiqizwe 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 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.
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 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) 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 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) 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. 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.Impahla ngemva nje kokuqiniswa isezingeni lokushisa eliphezulu eduze nendawo yokuncibilika futhi ine-stress yesivuno esiphansi kakhulu.Amagagasi anamandla e-ultrasonic angabangela ukugeleza kwepulasitiki ukuze kushintshe ukwakheka kokusanhlamvu kwezinto ezishisayo ezisanda kuqina.Nokho, idatha yokuhlola enokwethenjelwa ekuncikeni kwezinga lokushisa kwe-ield stress of yields{15K} iyatholakala ku-~(T15K) (bheka Umfanekiso 8) .Ngakho-ke, ukuze sihlole 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 kwendawo yokuncibilika.Ukubala ukucindezeleka kwesivuno, sasebenzisa inqubo yokuphumula yokucindezeleka ye-MD echazwe ku-1,30,7,7,7,7,7,7,7,7,7,7,7,7,7,7. izibalo, 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 wokushisa iboniswa ku-Fig. 8 kanye nedatha yokuhlola etholakalayo kanye nokunye ukuhlaziya,808,8179
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 ye-MD yezinga elikhulu kulolu cwaningo ichazwa ngokuthi \(\vartriangleleft\) yekristalu eyodwa engapheli engenasici kanye \(\vartriangleright\) yezinhlamvu ezinomkhawulo kucatshangelwa usayizi wokusanhlamvu omaphakathi nge-Hall-Petch Relation Dimensions\(d = 50~m\}\text).
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.
I-Liu, Y. et al.I-Microstructural evolution kanye nezakhiwo zokukhanda ze-in situ TiB2/AlSi10Mg izinhlanganisela nge-laser selective melting [J].J. I-Alloys.compound.853, 157287. https://doi.org/10.1016/j.jallcom.2020.157287 (2021).
Gao, S. et al.Recrystallization grain boundary engineering of laser selective melting of 316L insimbi engagqwali [J]. Ijenali ye-Alma Mater.200, 366–377.https://doi.org/10.1016/j.actamat.2020.09.015 (2020).
I-Chen, X. & Qiu, C. In situ ukuthuthukiswa kwesamishi microstructures ene-ductility ethuthukisiwe ngokushisa kabusha nge-laser ye-laser-melted titanium alloys.science.Rep. 10, 15870.https://doi.org/10.1038/s41598-020-72627-x (2020).
I-Azarniya, A. et al.Ukwenziwa okungeziwe kwezingxenye ze-Ti-6Al-4V nge-laser metal deposition (LMD): inqubo, i-microstructure kanye nezakhiwo zemishini.J. I-Alloys.compound.804, 163–191.https://doi.org/10.1016/j.jallcom.2019.04.255 (2019).
I-Kumara, C. et al.I-Microstructural modelling ye-laser metal powder eqondise ukufakwa kwamandla kwe-Alloy 718.Engeza ku-.manufacture.25, 357–364.https://doi.org/10.1016/j.addma.2018.11.024 (2019).
Busey, M. et al.Parametric Neutron Bragg Edge Imaging Study of Additively Manufactured Samples Treated by Laser Shock Peening.science.Rep. 11, 14919.https://doi.org/10.1038/s41598-021-94455-3 (2021).
I-Tan, X. et al.I-Gradient microstructure kanye nezakhiwo zemishini ye-Ti-6Al-4V ehlanganiswe ngokungeziwe ngokuncibilika kwe-electron beam.Alma Mater Journal.97, 1-16.https://doi.org/10.1016/j.actamat.2015.06.036 (2015).