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Njira yatsopano yochokera pa kusungunuka kwa laser yosankha kulamulira microstructure ya mankhwala popanga ndondomeko ikupangidwa.Makinawa amadalira kubadwa kwa mafunde amphamvu kwambiri akupanga mu dziwe losungunuka ndi zovuta zowonjezereka-modulated laser irradiation.Kafukufuku woyesera ndi kuyerekezera manambala amasonyeza kuti makina olamulirawa ndi otheka mwaukadaulo ndipo akhoza kukhala osakanikirana bwino ndi makina osankhidwa a laser.
Kupanga zowonjezera (AM) za ziwalo zooneka ngati zovuta zakula kwambiri m'zaka makumi angapo zapitazi. Komabe, ngakhale kuti pali njira zambiri zopangira zowonjezera, kuphatikizapo kusankha laser kusungunuka (SLM) 1,2,3, kuyika kwachitsulo cha laser4,5,6, electron melting7,8 ndi ena9,10, Zigawozi zikhoza kukhala zolakwika. mitengo, ndi zovuta za kutenthetsa kuzungulira mu kusungunula ndi kusungunula zinthu 11, zomwe zimabweretsa kukula kwa mbewu za epitaxial ndi porosity yaikulu.12,13 anasonyeza kuti m'pofunika kulamulira matenthedwe gradients, kuzirala mitengo, ndi aloyi zikuchokera, kapena ntchito zina mantha thupi ndi kunja minda zosiyanasiyana katundu, monga ultrasound, kukwaniritsa zabwino equiaxed njere nyumba.
Zofalitsa zambiri zimakhudzidwa ndi zotsatira za chithandizo cha kugwedezeka pa ndondomeko ya solidification mu njira zowonongeka14,15.Komabe, kugwiritsa ntchito kumunda kwakunja kwa kusungunula kochuluka sikumapanga zinthu zomwe zimafunidwa microstructure.Ngati kuchuluka kwa gawo lamadzimadzi ndi kochepa, zinthu zimasintha kwambiri. ,25,26,27, arc stirring28 ndi oscillation29, electromagnetic zotsatira pa pulsed plasma arcs30,31 ndi njira zina32 zaganiziridwa .Gwiritsani gawo lapansi pogwiritsa ntchito gwero lakunja lapamwamba kwambiri la ultrasound (pa 20 kHz) . kupanga crystallites latsopano kudzera cavitation.
Mu ntchito iyi, ife anafufuza kuthekera kwa kusintha njere dongosolo austenitic zosapanga dzimbiri zitsulo ndi sonicating dziwe losungunuka ndi mafunde phokoso kwaiye ndi kusungunuka laser itself.The mphamvu kusinthasintha kwa chochitika laser poizoniyu pa kuwala absorbing sing'anga zotsatira m'badwo wa akupanga mafunde, amene kusintha microstructure mu cheza chosindikizira alipo SLMD kuyesera mosavuta. Ntchitoyi inkachitidwa pa mbale zachitsulo zosapanga dzimbiri zomwe mawonekedwe ake adawonetsedwa ndi kuwala kosinthika kwa laser radiation.Choncho, mwaukadaulo, chithandizo cha laser padziko lapansi chimachitidwa.
Pamene akupanga nyanga yochokera akupanga mankhwala, ndi akupanga mphamvu ya kuyimirira phokoso yoweyula amagawidwa mu chigawo chimodzi, pamene laser-induced akupanga mwamphamvu kwambiri anaikira pafupi ndi pamene laser poizoniyu amatengeka.Kugwiritsa sonotrode mu SLM ufa bedi maphatikizidwe makina ndi zovuta chifukwa pamwamba pamwamba pa bedi ufa pali ponseponse poyera. Kupanikizika kwa coustic kuli pafupi ndi zero ndipo kuthamanga kwa tinthu kumakhala ndi matalikidwe apamwamba pamwamba pa pamwamba pa gawo lonselo. Kuthamanga kwa phokoso mkati mwa dziwe lonse losungunuka silingathe kupitirira 0.1% ya kuthamanga kwakukulu komwe kumapangidwa ndi mutu wowotcherera, chifukwa kutalika kwa mafunde a ultrasonic ndi mafupipafupi a 20 kHz muzitsulo zosapanga dzimbiri ndi \ (~\ sim) nthawi zambiri ndi \ (\ 3 \ sim) kuposa 0 . \zolemba {mm}\).Choncho, zotsatira za ultrasound pa cavitation zingakhale zazing'ono.
Tikumbukenso kuti ntchito kwambiri-modulated laser cheza pa mwachindunji laser mafunsidwe zitsulo ndi malo yogwira kafukufuku35,36,37,38.
The matenthedwe zotsatira laser poizoniyu chochitika pa sing'anga ndi maziko pafupifupi zonse processing zipangizo laser njira 39, 40, monga kudula 41, kuwotcherera, kuumitsa, kubowola 42, kuyeretsa pamwamba, alloying pamwamba, pamwamba kupukuta 43, etc.materials processing luso ndi mwachidule zotsatira zoyambirira mu ndemanga zambiri ndi monographs 5, 44, 46 .
Tikumbukenso kuti chilichonse sanali stationary kanthu pa sing'anga, kuphatikizapo lasing kanthu pa choyamwitsa sing'anga, kumabweretsa chisangalalo cha mafunde lamayimbidwe mmenemo ndi mochuluka kapena pang'ono Efficient.Poyamba, cholinga chachikulu chinali pa laser excitation wa mafunde zamadzimadzi ndi njira zosiyanasiyana matenthedwe excitation wa phokoso (matenthedwe kufutukuka, evaporation, voliyumu kusintha, 4 monograph, transiction 4, 8 etc.) s50, 51, 52 imapereka kusanthula kwamalingaliro kwa njirayi ndi momwe mungagwiritsire ntchito.
Nkhanizi zinakambidwa pamisonkhano yosiyanasiyana, ndipo kutengeka kwa laser kwa ultrasound kumagwiritsidwa ntchito m'mafakitale onse a laser technology53 ndi medicine54.Chifukwa chake, tingaganize kuti mfundo yaikulu ya ndondomeko yomwe pulsed laser kuwala imachita pa sing'anga yoyamwitsa yakhazikitsidwa.Kuyendera kwa laser ultrasonic kumagwiritsidwa ntchito pozindikira chilema cha SLM-chopangidwa,56 zitsanzo5.
Zotsatira za mafunde opangidwa ndi laser pazida ndi maziko a laser shock peening57,58,59, yomwe imagwiritsidwanso ntchito pochiza pamwamba pa magawo opangidwa mowonjezera60.
Kuyesera kunachitika kuti afufuze zotsatira zomwe zingatheke za madera osiyanasiyana a thupi pa microstructure ya zinthu zolimba. Chithunzi chogwira ntchito cha kukhazikitsidwa koyesera chikuwonetsedwa mu Chithunzi 1.A pulsed Nd:YAG solid-state laser yomwe ikugwira ntchito mumayendedwe omasuka (nthawi ya pulse \ (\ tau _L \ sim 150 ~ \ upmu \ text) inagwiritsidwa ntchito ndi fyuluta yopita kupyola muyeso wa laser. Kutengera kuphatikizika kwa zosefera zosalowerera ndale, mphamvu ya pulse pa chandamale imasiyanasiyana kuchokera \(E_L \ sim 20~\text {mJ}\) mpaka \(E_L \ sim 100~\text {mJ}\) .Mtsinje wa laser womwe ukuwonekera kuchokera ku splitter yamtengo umaperekedwa ku chithunzithunzi, mafotolo amtundu wa data ndi ma calorie ofananira nthawi yayitali (chithunzi chamtundu wa data ndi ma calorie otalikirapo) ing \(1~\text {ms}\)) amagwiritsidwa ntchito kuti adziwe zomwe zachitika ndikuwonetseredwa kuchokera ku chandamale, ndi mamita awiri amagetsi (photodiodes okhala ndi nthawi yochepa yoyankha \(<10~\text {ns}\)) kuti adziwe zomwe zinachitika ndikuwonetsa mphamvu ya kuwala.Ma Calorimeters ndi mamita amphamvu adayesedwa kuti apereke zikhalidwe mu mayunitsi absolute pogwiritsa ntchito detector X0-D-Selectric 3 Gen-S1c 2-D detector XL-2-D detector X1c artec electric XL-2-D detector X-1c artemot {ns} galasi loyikidwa pa malo chitsanzo. Yang'anani mtengo pa chandamale pogwiritsa ntchito lens (Antireflection zokutira pa \(1.06 \upmu \ text {m}\), focal kutalika \(160~\text {mm}\)) ndi m'chiuno chandamale pamwamba chandamale 60– \(100~\upmu\text {m}\).
Chojambula chogwira ntchito chokonzekera kuyesa: 1-laser;2 - laser mtengo;3-sefa yosalowerera ndale;4 - synchronized photodiode;5 - chowotcha matabwa;6—chizungulire;7 - calorimeter ya mtengo wa zochitika;8 - calorimeter ya mtengo wonyezimira;9 - mita yamagetsi yamagetsi;10 - kuwonetsa mita yamagetsi;11 - kuyang'ana mandala;12 - galasi;13 - chitsanzo;14 - burodibandi piezoelectric transducer;15 - 2D chosinthira;16 - kuika microcontroller;17 - gawo lolumikizana;18 - njira yopezera digito zamakina ambiri okhala ndi zitsanzo zosiyanasiyana;19 - kompyuta yanu.
Akupanga mankhwala ikuchitika motere.Laser imagwira ntchito mwaufulu-kuthamanga mode;choncho nthawi ya laser pulse ndi \(\tau _L \sim 150~\upmu \text {s}\), yomwe imakhala ndi nthawi zingapo pafupifupi \ (1.5~\upmu \text {s } \) iliyonse. Maonekedwe osakhalitsa a laser pulse ndi sipekitiramu yake imakhala ndi kutsika kwafupipafupi kwafupipafupi, ~ 7 pafupipafupi ndi ma envelopu afupipafupi. malemba {MHz}\), monga momwe tawonetsera pa Chithunzi 2.- Envulopu yafupipafupi imapereka kutentha ndi kusungunuka kotsatira ndi kutuluka kwa zinthu, pamene gawo lalikulu lafupipafupi limapereka kugwedezeka kwa ultrasonic chifukwa cha photoacoustic effect.The waveform ya ultrasonic pulse yopangidwa ndi laser makamaka imatsimikiziridwa ndi mawonekedwe a nthawi ya mphamvu ya laser pulse.Amachokera ku \(7~\text {kHz}\) kupita ku \ (2~\text {MHz}\), ndipo mafupipafupi apakati ndi \(~ 0.7~\text {MHz}\) .Acoustic pulses chifukwa cha photoacoustic effect anajambulidwa pogwiritsa ntchito ma transducers a burodiband piezoelectric opangidwa ndi mafilimu a polyvinylidene fluoride.Mawonekedwe ojambulidwa ndi mawonekedwe a pulse 2 ndi mawonekedwe a pulse laser ayenera kukhala mawonekedwe a Fispectrum. mawonekedwe amtundu wa laser wopanda ntchito.
Kugawa kwakanthawi kwa laser pulse intensity (a) ndi kuthamanga kwa mawu (b) kumbuyo kwachitsanzo, mawonekedwe (mapindikira abuluu) amtundu umodzi wa laser pulse (c) ndi kugunda kwa ultrasound (d) kupitilira 300 laser pulses (njira yofiyira).
Titha kusiyanitsa momveka bwino zigawo zotsika kwambiri komanso zamtundu wapamwamba wa chithandizo chamankhwala chofanana ndi envelopu yotsika kwambiri ya laser pulse ndi kusinthasintha kwapamwamba kwambiri, motero.Kutalikirana kwa mafunde omveka opangidwa ndi envelopu ya laser pulse kupitirira \(40 ~\text {cm}\);Choncho, zotsatira zazikulu za burodibandi mkulu-pafupipafupi zigawo za amayimbidwe chizindikiro pa microstructure chikuyembekezeka.
Zochita zakuthupi mu SLM ndizovuta ndipo zimachitika nthawi imodzi pazigawo zosiyana za malo ndi zanthawi.Choncho, njira zambiri zimakhala zoyenera kwambiri pakuwunika kwamalingaliro a SLM.Mafanizo a masamu ayenera poyamba kukhala amitundu yambiri.The mechanics ndi thermophysics ya multiphase medium "solid-liquid melt" yogwirizana ndi makhalidwe a inert katundu mu mpweya wokwanira wa SLM.
Kutentha ndi kuziziritsa mpaka \(10^6~\text {K}/\text {s}\) /\text{ chifukwa chakuwalitsa kwa laser komwe kumakhala ndi mphamvu zochulukirapo mpaka \(10^{13}~\text {W} cm}^2\).
Mzunguliro wosungunuka wosungunuka umakhala pakati pa 1 ndi \(10~\text {ms}\), zomwe zimathandizira kulimba kofulumira kwa malo osungunuka panthawi yozizirira.
Kutentha kofulumira kwa chitsanzo pamwamba kumapangitsa kuti mapangidwe apamwamba a thermoelastic apangidwe pamtunda wosanjikiza. Zokwanira (mpaka 20%) gawo la ufa wosanjikiza ndi evaporated63, zomwe zimapangitsa kuti pakhale mphamvu yowonjezera pamtunda chifukwa cha laser ablation. Kuti mupeze deta yolondola yokhudzana ndi kupsinjika kwa m'deralo ndi kugawa kwapang'onopang'ono, kuyerekezera kwa mesoscopic kwa vuto la elastic deformation lomwe limagwirizanitsidwa ndi kutentha ndi kusamutsidwa kwakukulu kumachitika.
Ma equation olamulira amtunduwu amaphatikizanso (1) kusakhazikika kwa kutentha komwe kumadalira momwe matenthedwe amayendera (ufa, kusungunuka, polycrystalline) ndi kutentha, (2) kusinthasintha kwa kusintha kwa zotanuka pambuyo potulutsa kopitilira muyeso ndi equation yowonjezera ya thermoelastic. x.Kuthamanga kwa misa kumatanthauzidwa kutengera kuwerengera kwa mphamvu ya nthunzi yochuluka ya zinthu zomwe zimatuluka nthunzi.Ubale wa elastoplastic stress-strain umagwiritsidwa ntchito pamene kupanikizika kwa thermoelastic kumayenderana ndi kusiyana kwa kutentha.Kwa mphamvu yadzina \(300~\text {W}\), mafupipafupi \(10^5~\\text \Hz~ com \ (0} intermit {0} ndi \ 0} intermit {0} ndi \ 0} intermit {0} \ (0} \ 0) mphamvu yamtengo wapakati.
Chithunzi cha 3 chikuwonetsa zotsatira za kayeseleledwe ka manambala a chigawo chosungunula pogwiritsa ntchito masamu a macroscopic. Kuzama kwa malo osakanikirana ndi \(200~\upmu \text {m}\) (\(100~\upmu \text {m}\) radius) ndi \(40~\upmu \mawu olembedwa {m}~) amawonetsa kuya kwa nthawi {0} ndi kusiyanasiyana kwanthawi {0}\) komwe kumawonetsa kuzama kwa {0} {0}\}. \) chifukwa cha kuchuluka kwapakatikati kwa kusinthasintha kwa kugunda kwa mtima.Kutentha \(V_h\) ndi kuziziritsa \(V_c\) kuli pa dongosolo la \(10^7\) ndi \(10^6~\text {K}/\text {s}\), motsatana.Zizindikirozi zikugwirizana bwino ndi kusanthula kwathu kwam'mbuyo kwa mag(V_)kusiyana kwa mag(V_) ndi \(V)\64\64. kutenthedwa kwambiri kwapamwamba kwapamwamba, kumene kutenthetsa kwa kutentha kwa gawo lapansi sikukwanira kuchotsa kutentha.Chifukwa chake, pa \(t=26~\upmu \text {s}\) kutentha kwapamwamba kumakwera kwambiri \(4800 ~\text {K}\)) Kutuluka kwamphamvu kwa zinthu kungapangitse kuti sampuli ikhale yoponderezedwa kwambiri.
Nambala kayeseleledwe zotsatira za melting zone wa single laser pulse annealing pa 316L chitsanzo mbale.Nthawi yochokera kuchiyambi cha kugunda kwa kuya kwa dziwe losungunuka kufika pa mtengo wapamwamba ndi \(180~\upmu\text {s}\).Isotherm\(T = T_L = 1723~.. Lellows the solid of the solid & isosotherm)'s the solid boundary (K}). zimagwirizana ndi kupsinjika kwa zokolola zomwe zimawerengedwa ngati ntchito ya kutentha mu gawo lotsatira.Chifukwa chake, mu domain pakati pa isolines awiri (T = T_L \) ndi isobars \ (\ sigma =\ sigma _V (T) \)), gawo lolimba limakhala ndi katundu wamphamvu wamakina , zomwe zingayambitse kusintha kwa microstructure.
Chotsatirachi chikufotokozedwanso mu Chithunzi 4a, kumene kupanikizika kwapakati pa malo osungunuka kumapangidwira ngati ntchito ya nthawi ndi mtunda kuchokera pamwamba.Choyamba, khalidwe la kupanikizika likugwirizana ndi kusinthasintha kwa mphamvu ya laser pulse yomwe ikufotokozedwa mu Chithunzi 2 pamwambapa.Kuthamanga kwakukulu \ malemba{s}\) pafupifupi \ (10 ​​~\ text {MPa} ~ 6 d, c (c) m'dera lomwe linkawonedwa {MPa} ~ 6, c (c) = m'dera lomwe linkawonedwa {MPa}cond\) kuthamanga pa ulamuliro malo ali chimodzimodzi oscillation makhalidwe monga pafupipafupi \ (500 ~ \ malemba {kHz} \) .Izi zikutanthauza kuti akupanga kuthamanga mafunde kwaiye pamwamba ndiyeno kufalitsa mu gawo lapansi.
Makhalidwe owerengedwera a malo ozungulira pafupi ndi malo osungunuka akuwonetsedwa mu Chithunzi 4b. Laser ablation ndi thermoelastic stress imapanga mafunde osinthika osakanikirana omwe amafalikira mu gawo lapansi.Monga momwe zikuwonekera kuchokera ku chithunzichi, pali magawo awiri a kupsinjika maganizo. Pakati pa gawo loyamba la \ (t <40 ~\upmu \ MP a [8] kupanikizika \" , kukweza kwa MP \ text {s } } } } } } } } } } , , , ,,,,,,,,,,,,,,,,,,,,,,,,,, trakita,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,. kupsinjika kwapamwamba.Kupsinjika kumeneku kumachitika chifukwa cha kutulutsa kwa laser, ndipo palibe kupsinjika kwa thermoelastic komwe kunawonedwa m'malo owongolera chifukwa gawo loyambilira lomwe limakhudzidwa ndi kutentha linali laling'ono kwambiri.Pamene kutentha kumatayidwa mu gawo lapansi, malo owongolera amapanga kupsinjika kwakukulu kwa thermoelastic pamwamba pa \(40 ~\text {MPa}\).
Zomwe zapezedwa modulated zopanikizika zimakhudza kwambiri mawonekedwe olimba-zamadzimadzi ndipo zingakhale njira yoyendetsera kayendetsedwe kazitsulo.Kukula kwa malo ozungulira ndi 2 mpaka 3 nthawi zazikulu kuposa zomwe zimasungunuka. 300 ndi \(800~\upmu \text {m}\) kutengera nthawi yomweyo.
Choncho, zovuta kusintha kwa pulsed laser annealing kumabweretsa akupanga effect.The microstructure kusankha njira ndi yosiyana ngati poyerekeza ndi SLM popanda akupanga loading.Deformed kusakhazikika zigawo kumabweretsa nthawi m'zinthu psinjika ndi kutambasula mu olimba phazi.Chotero, mapangidwe malire a tirigu ndi subgrain malire a subgrain atha kusinthidwa, motero amatha kusinthidwa kukhala zotheka. kupanga mawonekedwe a pulse modulation-induced ultrasound-driven SLM prototype.Pankhaniyi, piezoelectric inductor 26 yogwiritsidwa ntchito kwina ikhoza kuchotsedwa.
(a) Kupanikizika ngati ntchito ya nthawi, yowerengedwa pa mtunda wosiyana kuchokera pamtunda 0, 20 ndi \(40~\upmu \text {m}\) motsatira mbali ya symmetry.
Kuyesera kunachitika pa AISI 321H zitsulo zosapanga dzimbiri mbale zokhala ndi miyeso \ (20 \ nthawi 20 \ nthawi 5 ~ \ zolemba {mm} \). Pambuyo pa kugunda kwa laser iliyonse, mbale imasuntha \ (50 ~\upmu \ text {m}\), ndipo chiuno cha laser chandamale pamwamba pa chandamale chiri pafupi \ (100 ~ p ~ 5 / 5 / 15 / 15 / 10 / 10 / 10 / 10 / 10 / 15 / 20 / 20 / 2013 / 10 / 10 / 10 / 10 / 10 / 15 / 2014 / 100 / 100 / 5 / 20 / 20 / 2013 / 10 / 10 / 10 / 10 / 2013 / 12 / 2013) Nthawi zonse, malo osungunuka anali sonicated, malingana ndi gawo la oscillatory la laser radiation.Izi zimabweretsa kuchepetsedwa kwa 5-kuchepetsa pafupifupi dera lambewu.
Ma subplots (a,d,g,j) ndi (b,e,h,k) - microstructure of laser melted regions, subplots (c,f,i,l) - kugawa madera a mbewu zamitundu.Shading imayimira tinthu tating'onoting'ono towerengera histogram.Mitundu imayenderana ndi madera ambewu (onani mipiringidzo yamitundu yomwe ili pamwamba pa histogram. Magawo (ac) amafanana ndi chitsulo chosapanga dzimbiri chosasunthika, ndi ma subplots (df), (gi), (jl) amagwirizana ndi 1, 3 ndi 5 remelts.
Popeza mphamvu ya laser pulse sikusintha pakati pa maulendo otsatirawa, kuya kwa malo osungunuka ndi ofanana.Choncho, njira yotsatirayi "imaphimba" yapitayi.
Mbewu kuyenga mwina chifukwa cha kuzirala mofulumira kwa dziwe wosungunuka65.Another seti zoyesera inachitika pamene pamwamba pa mbale zosapanga dzimbiri zitsulo (321H ndi 316L) anali poyera mosalekeza yoweyula laser cheza mu mlengalenga (mkuyu. 6) ndi vacuum (mkuyu. 7) .The avareji mphamvu laser (3000 W ndi molten dziwe) ndi kutseka dziwe laser mphamvu (3000 W ndi molten dziwe, kutseka dziwe ndi kutseka dziwe ndi dziwe laser molten ndi kuzama dziwe, 3000 W ndi molten dziwe lakuya ndi kuzama kwa dziwe la laser). Nd: LAG laser mumayendedwe omasuka.
Microstructure ya dera losungunuka la laser la laser yowonjezereka (300 W mphamvu yosalekeza, 200 mm / s scan speed, AISI 321H chitsulo chosapanga dzimbiri).
(a) Microstructure ndi (b) electron backscatter diffraction chithunzi cha laser melting zone ya vacuum continuous wave laser (mphamvu yosalekeza 100 W, scanning speed 200 mm / s, AISI 316L chitsulo chosapanga dzimbiri) \ (\ sim 2 ~ \ text {mbar } \).
Choncho, zikuonekeratu kuti zovuta kusinthasintha kwa laser kugunda mwamphamvu amakhudza kwambiri chifukwa microstructure.Timakhulupirira kuti zimenezi ndi makina m'chilengedwe ndipo zimachitika chifukwa cha m'badwo wa akupanga kugwedera kufalitsa kuchokera watsitsidwa pamwamba pa Sungunulani mozama mu sampuli.Zotsatira zofananazo zinapezedwa mu 13, 26, 34, 34, 34, 26, 34, 34, 6, 26, 34, 26, 34, 34, 26, 34, 6, 6, 34, 6, 34, 6, 26, 34, 26, 34, 34, 6, 6, 34, 26, 34, 34, 6, 6, 34, 6. ity ultrasound mu zipangizo zosiyanasiyana kuphatikizapo Ti-6Al-4V aloyi 26 ndi zitsulo zosapanga dzimbiri 34 zotsatira za.The zotheka limagwirira amaganiziridwa motere.Intense ultrasound ingayambitse lamayimbidwe cavitation, monga kuwonetseredwa mu ultrafast in situ synchrotron X-ray imaging.Kugwa kwa cavitation thovu ~ 0 }\) 69.Mafunde odabwitsa oterowo akhoza kukhala amphamvu mokwanira kuti alimbikitse kupangika kwa nyukiliya yolimba kwambiri muzamadzimadzi zambiri, kusokoneza kapangidwe kake kambewu kakang'ono kagawo kagawo kakang'ono kopanga zowonjezera.
Apa, ife akamufunsire lina limagwirira ntchito structural kusinthidwa ndi kwambiri sonication.The nkhani atangolimbitsa ndi pa kutentha kwambiri pafupi ndi malo osungunuka ndipo ali otsika kwambiri zokolola stress.Intense akupanga mafunde zingachititse pulasitiki otaya kusintha njere dongosolo la zinthu otentha basi solidified. 8) .Chifukwa chake, kuti tiyese malingaliro, tinkachita mafanizidwe a ma molecular dynamics (MD) a mawonekedwe a Fe-Cr-Ni ofanana ndi AISI 316 L zitsulo pofuna kuyesa khalidwe la kupsinjika kwa zokolola pafupi ndi malo osungunuka. tomic Model (EAM) kuchokera ku 74.MD zofananitsa zinkagwiritsidwa ntchito pogwiritsa ntchito zizindikiro za LAMMPS 75,76. Tsatanetsatane wa MD kufananitsa zidzasindikizidwa kwina.Zotsatira za MD zowerengera za kupsinjika kwa zokolola monga ntchito ya kutentha zikuwonetsedwa mu Chithunzi 8 pamodzi ndi deta yoyesera yopezeka ndi zowunikira zina77,78,79,82,80.
Kupsinjika kwa zokolola za AISI kalasi ya 316 austenitic chitsulo chosapanga dzimbiri ndi kapangidwe kachitsanzo motsutsana ndi kutentha kwa zoyerekeza za MD. Miyezo yoyesera kuchokera ku maumboni: (a) 77, (b) 78, (c) 79, (d) 80, (e) 81.lozerani. .Zotsatira zazikulu za kayesedwe ka MD mu phunziroli zimatchedwa \(\vartriangleleft\) kwa kristalo wopanda chilema wopanda malire ndi \(\vartriangleright\) panjere zomalizira poganizira kukula kwambewu kudzera mu Hall-Petch relation Dimensions\(d = 50~\upmu\text {m}\).
Zitha kuwoneka kuti pa \(T> 1500 ~\text {K}\) kupsinjika kwa zokolola kumatsika pansi \(40~\text {MPa}\) .Kumbali inayi, kuyerekezera kumaneneratu kuti laser-generated ultrasonic amplitude kuposa \(40~\text {MPa}\) (onani mkuyu 4b), yomwe imakhala yokwanira kutulutsa pulasitiki yolimba.
Mapangidwe ang'onoang'ono a 12Cr18Ni10Ti (AISI 321H) austenitic chitsulo chosapanga dzimbiri pa SLM adafufuzidwa moyesera pogwiritsa ntchito gwero la laser lovuta kwambiri.
Kuchepetsa kukula kwa mbewu m'malo osungunuka a laser kunapezeka chifukwa cha kusungunuka kwa laser mosalekeza pambuyo pa 1, 3 kapena 5 kupita.
Macroscopic modeling amasonyeza kuti akuyerekeza kukula kwa dera kumene akupanga mapindikidwe angakhudze bwino solidification kutsogolo ndi mpaka \(1~\text {mm}\).
Chitsanzo cha microscopic MD chimasonyeza kuti mphamvu zokolola za AISI 316 austenitic zosapanga dzimbiri zimachepetsedwa kwambiri mpaka \ (40 ~\ text {MPa}\) pafupi ndi malo osungunuka.
Zotsatira zomwe zapezedwa zikuwonetsa njira yowongolera ma microstructure azinthu pogwiritsa ntchito makina opangidwa ndi laser modulated ndipo zitha kukhala maziko opangira zosintha zatsopano zaukadaulo wa pulsed SLM.
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