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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 zaposachedwa. Komabe, ngakhale pali njira zambiri zopangira zowonjezera, kuphatikizapo kusankha laser melting (SLM) 1,2,3, kuyika kwachitsulo cha laser4,5,6, electron melting7,8 ndi ena9,10, Zigawozi zikhoza kukhala zolakwika. ma gradients, kuzizira kwapamwamba, ndi zovuta zowonongeka kwa kutentha pakusungunuka ndi kusungunula zinthu 11, zomwe zimayambitsa kukula kwambewu ya 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.
Zolemba zambiri zimakhudzidwa ndi zotsatira za chithandizo cha kugwedezeka pa ndondomeko yolimba mu njira zochiritsira zowonongeka14,15.Komabe, kugwiritsa ntchito munda wakunja kwa kusungunuka kwakukulu sikumapanga chinthu chofunika kwambiri cha microstructure. minda16,17,18,19,20,21,22,23,24,25,26,27, arc stirring28 ndi oscillation29, electromagnetic zotsatira pa pulsed plasma arcs30,31 ndi njira zina32 zakhala zikuganiziridwa .Gwiritsani ntchito gawo lapansi pogwiritsa ntchito njere ultrasound gwero la ultrasound gwero lamphamvu kwambiri. kuyengedwa ndi chifukwa cha kuchuluka constitutive subcooling zone chifukwa yafupika kutentha gradient ndi ultrasound kuwongola 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 kusungunuka laser itself.The mphamvu kusinthasintha kwa chochitika laser poizoniyu pa kuwala absorbing sing'anga zotsatira mu m'badwo wa akupanga mafunde, amene kusintha microstructure mu ma radiation omwe alipo moduten akhoza kukhala Integrated ma radiation a SLMD moduten mosavuta. Kuyesera mu ntchitoyi kunachitika pa mbale zachitsulo zosapanga dzimbiri zomwe mawonekedwe ake adawonetsedwa ndi kuwala kosinthika kwa laser radiation.Choncho, mwaukadaulo, chithandizo cha laser padziko lapansi chimachitika. "mankhwala a laser volume".
Pamene akupanga nyanga yochokera akupanga mankhwala, akupanga mphamvu ya kuyimirira phokoso yoweyula amagawidwa mu chigawo chimodzi, pamene laser-anachititsa akupanga mwamphamvu kwambiri anaikira pafupi ndi pamene laser poizoniyu amatengeka.Kugwiritsa ntchito sonotrode mu SLM ufa bedi maphatikizidwe makina ndi zovuta chifukwa pamwamba pamwamba pa bedi ufa ndi kuwululidwa pamwamba palibe ma radiation pamwamba pa ma radiation a laser ayenera kukhalabe. Gawo.Chifukwa chake, kupsinjika kwamayimbidwe 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 \ ~ ~ zitsulo zosapanga dzimbiri \ 3 \ chitsulo chosapanga dzimbiri \ ~ ~ 0m. zochepa kuposa \(\ sim 0.3 ~\text {mm}\).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 .
Tiyenera kudziwa kuti chilichonse chomwe sichinayime pa sing'anga, kuphatikiza kuchitapo kanthu pa sing'anga yoyamwa, kumabweretsa chisangalalo cha mafunde amamvekedwe mmenemo ndi mphamvu zambiri kapena zochepa. Poyambirira, cholinga chachikulu chinali pa laser excitation ya mafunde muzamadzimadzi ndi njira zosiyanasiyana zokometsera matenthedwe a phokoso (kuwonjezeka kwa kutentha, evaporation, kusintha kwa voliyumu 4 gawo, 8 ndi zina zotero. 49. Ma monographs ambiri50, 51, 52 amapereka kusanthula kwamalingaliro kwa njirayi ndi momwe angagwiritsire 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 \(\ tau _L \ sim 150~\upmu \ text was used of laser s. Zosefera ndi dongosolo la mbale yogawanitsa matabwa. Malingana ndi kuphatikiza kwa zosefera zopanda ndale, mphamvu ya pulse pa chandamale imasiyanasiyana kuchokera \ (E_L \ sim 20 ~ \ text {mJ} \) mpaka \ (E_L \ sim 100 ~\ text {mJ}\) .Mtsinje wa laser womwe umawonekera kuchokera ku beam splitter ndi data yamtundu wa simuriquisi yomwe imadyetsedwa ku ma calorie amtundu wa simuriquisi. (ma photodiodes okhala ndi nthawi yayitali yoyankha kuposa \(1~\text {ms}\)) amagwiritsidwa ntchito kuti adziwe zomwe zidachitika ndikuwonetseredwa kuchokera pa chandamale, ndi ma mita awiri amagetsi (photodiodes okhala ndi nthawi yayitali yoyankha \(<10~\text {ns}\)) kuti adziwe zomwe zidachitika ndikuwonetsa mphamvu yamagetsi. XLP12-3S-H2-D0 ndi galasi la dielectric loyikidwa pamalo a chitsanzo. Yang'anani mtengowo pa chandamale pogwiritsa ntchito lens (Antireflection coating pa \(1.06 \upmu \ text {m}\), focal length \(160~\text {mm}\)) ndi chiuno chamtengo pa chandamale pamwamba 1\\\\\\\\\\\\\ \\ mawu \\ mmwamba \ 000m 60m).
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.Mawonekedwe osakhalitsa a laser pulse ndi sipekitiramu yake imakhala ndi kutsika kwafupipafupi kwafupipafupi, kufupikitsa kwafupipafupi ndi ma envulopu \ (0.7 ~ \ zolemba {MHz} \), monga momwe tawonetsera mu Chithunzi 2.- Envulopu yafupipafupi imapereka kutentha ndi kusungunuka kotsatira ndi kutuluka kwa zinthuzo, pamene gawo lalikulu lafupipafupi limapereka kugwedezeka kwa ultrasonic chifukwa cha photoacoustic effect.The waveform wa ultrasonic pulse opangidwa ndi laser makamaka amatsimikiziridwa ndi mawonekedwe a nthawi 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 burodibandi piezoelectric opangidwa ndi mafilimu a polyvinylidene fluoride.Mawonekedwe ojambulidwa akuwonetsedwa mu mawonekedwe a mawonekedwe a Figure. laser pulses ndi mtundu wa laser-running mode laser.
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.
Njira 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 sing'anga "solid-liquid melt" yogwirizana ndi makhalidwe a inert katundu mu mpweya wokwanira wa SLM womwe ungathe kufotokozedwa monga mpweya wokwanira wa mpweya. amatsatira.
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 kwachangu kwachitsanzo kumapangitsa kuti pakhale kupanikizika kwapamwamba kwa thermoelastic pamtunda wosanjikiza.Zokwanira (mpaka 20%) gawo la ufa wonyezimira umasungunuka kwambiri63, zomwe zimapangitsa kuti pakhale kupanikizika kowonjezera pamtunda chifukwa cha laser ablation. m'badwo wa akupanga kupsyinjika mafunde kuti kufalitsa kuchokera padziko lapansi kwa gawo lapansi.Kuti kupeza molondola kachulukidwe deta pa m'deralo nkhawa ndi mavuto kugawa, ndi mesoscopic kayeseleledwe wa zotanuka mapindikidwe vuto conjugated kwa kutentha ndi misa kutengerapo ikuchitika.
Ma equation olamulira amtunduwu amaphatikizanso (1) kusakhazikika kwa kutentha komwe kumadalira momwe kutentha kumatengera gawo (ufa, kusungunuka, polycrystalline) ndi kutentha, (2) kusinthasintha kwa kusinthika kwa zotanuka pambuyo potulutsa kopitilira muyeso ndi equation yowonjezera ya thermoelastic. ndi evaporative flux.Kuthamanga kwa misa kumatanthauzidwa potengera kuwerengera kwa mpweya wochuluka wa nthunzi wa zinthu zomwe zimatuluka.Ubale wokwanira wa elastoplastic stress-strain umagwiritsidwa ntchito pamene kupanikizika kwa thermoelastic kumakhala kofanana ndi kusiyana kwa kutentha. \(200~\upmu \text {m}\ ) ya m'mimba mwake yogwira mtima.
Chithunzi 3 chikuwonetsa zotsatira za kayeseleledwe ka manambala a chigawo chosungunula pogwiritsa ntchito masamu a macroscopic. The diameter of the fusion zone ndi \(200~\upmu \text {m}\) (\(100~\upmu \text {m}\) radius) ndi \(40~\upmu \malemba {m}\) amawonetsa kuya kwake komwe kumawonetsa kutentha kwanthawi yayitali. \(100~\text {K}\) chifukwa cha kuchuluka kwapakatikati kwa kusinthasintha kwa kugunda kwa mtima. Kutentha \(V_h\) ndi kuziziritsa \(V_c\) mitengo ili pa dongosolo la \(10^7\) ndi \(10^6~\text {K}/\text {s}\), motsatana. Miyezo iyi ndi yogwirizana bwino \(V_h\) ndi \(V_c\) zimabweretsa kutenthedwa kofulumira kwa pamwamba, pomwe kuwongolera kwamafuta kupita ku gawo lapansi sikukwanira kuchotsa kutentha.Chifukwa chake, pa \(t=26~\upmu\text {s}\) kutentha kwa pamwamba kumakwera kwambiri \(4800~\text {K}\)) .
Nambala kayeseleledwe zotsatira za melting zone wa single laser pulse annealing pa 316L chitsanzo mbale.Nthawi kuyambira chiyambi cha kugunda mpaka kuya kuya kwa dziwe losungunuka kufika pa mtengo wapamwamba ndi \(180~\upmu\text {s}\).Isotherm\(T = T_L = 1723~.Mawu amadzimadzi pakati pa chigawo cholimba ndi iso \ isotherm) {K} (mizere yachikasu) imagwirizana ndi kupsinjika kwa zokolola zomwe zimawerengedwa ngati ntchito ya kutentha mu gawo lotsatira.Choncho, mu domain pakati pa isolines awiri (T = T_L \) 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 kusinthika kwa mphamvu ya laser pulse yomwe ikufotokozedwa mu Chithunzi 2 pamwambapa.Kuthamanga kwakukulu \ malemba{s}\) pafupifupi \(10~\\text {MPa}~ d,\) adawonedwa {MPa}~ d,\) = pa = = (MPa}~ d, \) kusinthasintha kwa m'deralo kuthamanga pa malo olamulira ali ofanana 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 zimapanga mafunde osinthika osakanikirana omwe amafalikira mu gawo lapansi.Monga momwe zikuwonekera kuchokera ku chithunzicho, pali magawo awiri a kupsinjika maganizo.Panthawi yoyamba ya \ (t <40~\upmu \ MP Mises \" } } , kukwera kwa MP ( 8) kumutu kwa mutu {ss}} kusinthasintha kofanana ndi kupanikizika kwa pamwamba.Kupsinjika kumeneku kumachitika chifukwa cha kutulutsa kwa laser, ndipo palibe kupanikizika kwa thermoelastic komwe kunawonedwa m'malo olamulira chifukwa malo oyambirira okhudzidwa ndi kutentha anali ochepa kwambiri.Pamene kutentha kumatayidwa mu gawo lapansi, malo olamulira amachititsa kuti pakhale kupanikizika kwakukulu kwa thermoelastic pamwamba pa \(40 ~\text {MPa}\).
Zomwe zapezedwa modulated kupsinjika maganizo zimakhudza kwambiri mawonekedwe olimba-zamadzimadzi ndipo akhoza kukhala njira yoyendetsera kayendetsedwe kazitsulo zolimba.Kukula kwa malo ozungulira ndi 2 mpaka 3 nthawi zazikulu kuposa za malo osungunuka. m'mimba mwake pakati pa 300 ndi \(800~\upmu \text {m}\) kutengera nthawi yomweyo.
Choncho, zovuta kusintha kwa pulsed laser annealing kumabweretsa akupanga effect.The microstructure kusankha njira 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 akhoza kusinthidwa monga zotheka m'munsimu. zomaliza zimapereka mwayi wopanga ma 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 ndi miyeso \ (20 \ 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 ~pm to beam paque) pamodzi njanji yemweyo kulimbikitsa remelting wa zinthu kukonzedwa kuti tirigu refinement.Nthawi zonse, zone remelted anali sonicated, malinga ndi oscillatory chigawo chimodzi cha laser radiation.Izi zimabweretsa kuposa 5-khola kuchepetsa pafupifupi tirigu area.Figure 5 limasonyeza mmene microstructure wa laser-kusungunuka dera kusintha ndi chiwerengero cha wotsatira remelting (pampu ya remelting).
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 zosapanga dzimbiri mbale zitsulo (321H ndi 316L) anali poyera mosalekeza yoweyula laser cheza mu mlengalenga (mkuyu. 6) ndi vacuum (mkuyu. 7) .The avareji laser mphamvu (3000 W ndi molten kuzama dziwe) kufupi ndi dziwe la laser (3000 W ndi molten kuzama) kufupi ndi dziwe lakuya (3000 W) zotsatira zoyesera za Nd: YAG 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 ali kwambiri zotsatira chifukwa microstructure.Timakhulupirira kuti zimenezi ndi makina m'chilengedwe ndipo zimachitika chifukwa cha m'badwo wa akupanga kugwedera kufalitsa kuchokera watsitsidwa pamwamba pa Sungunulani kwambiri mu sample.Similar zotsatira anapezedwa mu 13, 26, 34, 34, 6, 6, 34, 6, 26, 34, 34, 26, 34, 34, 34, 34, 34, 6, 34, 6, 34, 34, 26, 34, 34, 26, 34, 34, 6, 6, 26, 34, 34, 6, 6, 26, 34, 34, 6. kupereka mkulu-mphamvu ultrasound mu zipangizo zosiyanasiyana kuphatikizapo Ti-6Al-4V aloyi 26 ndi zitsulo zosapanga dzimbiri 34 chifukwa cha.The zotheka limagwirira akulingalira motere.Intense ultrasound zingachititse lamayimbidwe cavitation, monga anasonyeza ultrafast mu situ synchrotron X-ray kujambula.The kugwa kwa cavitation kugwedezeka mu zinthu zochititsa mantha za zinthu zochititsa mantha za cavitation. \(100~\text {MPa}\) 69.Mafunde odabwitsa oterowo akhoza kukhala amphamvu mokwanira kulimbikitsa mapangidwe amphamvu-gawo lolimba lagawo muzamadzimadzi zambiri, kusokoneza kapangidwe kambewu kakang'ono kagawo kagawo kakang'ono kopanga zowonjezera.
Apa, ife akamufunsire lina limagwirira udindo structural kusinthidwa ndi kwambiri sonication.The zinthu 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. (onani Chithunzi 8) .Choncho, kuti tiyese malingaliro, tinachita zofananira za ma molecular dynamics (MD) za Fe-Cr-Ni zofanana ndi zitsulo za AISI 316 L kuti tiyese khalidwe lachisokonezo cha zokolola pafupi ndi malo osungunuka. kuwerengera, tinagwiritsa ntchito Embedded Atomic Model (EAM) kuchokera ku 74.MD zofananitsa zinkagwiritsidwa ntchito pogwiritsa ntchito zizindikiro za LAMMPS 75,76. Tsatanetsatane wa MD kuyerekezera zidzasindikizidwa kwina.Zotsatira za MD zowerengera za kupsinjika kwa zokolola monga ntchito ya kutentha zikuwonetsedwa mu Chithunzi 8 pamodzi ndi deta yoyesera yopezeka ndi zina, 802,81779
Kupsinjika kwa zokolola za AISI giredi 316 austenitic chitsulo chosapanga dzimbiri ndi kapangidwe kachitsanzo motsutsana ndi kutentha kwa zoyerekeza za MD. Miyezo yoyeserera kuchokera ku maumboni: (a) 77, (b) 78, (c) 79, (d) 80, (e) 81.lozerani. laser-assisted additive production
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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