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Hoʻokumu ʻia kahi hana hou e pili ana i ka hoʻoheheʻe laser koho e hoʻomalu i ka microstructure o nā huahana i ka hana hana.
ʻO ka hana hoʻohui ʻana (AM) o nā ʻāpana paʻakikī i ulu nui i nā makahiki i hala iho nei. rates, a me ka paʻakikī o nā pōʻai wela i ka hoʻoheheʻe ʻana a me ka hoʻoheheʻe ʻana i ka mea 11, e alakaʻi i ka ulu ʻana o ka palaoa epitaxial a me ka porosity nui.12,13 ua hōʻike i ka pono e hoʻomalu i ka wela wela, nā helu hoʻoluʻu, a me ka hui pū ʻana, a i ʻole e hoʻopili i nā haʻalulu kino e nā kahua o waho o nā waiwai like ʻole, e like me ka ultrasound, e hoʻokō ai i nā hale palaoa equiaxed maikaʻi.
Nui nā puke e pili ana i ka hopena o ka vibration lapaʻau ma ke kaʻina hana solidification i nā kaʻina hoʻolei maʻamau 14,15. Akā naʻe, ʻo ka noi ʻana i kahi kahua waho i kahi hoʻoheheʻe nui ʻaʻole e hana i ka microstructure mea makemake. ,25,26,27, arc stirring28 and oscillation29, electromagnetic effects during pulsed plasma arcs30,31 and other ways32 have thoughted to the substrate using a external high-intensity ultrasound source (ma 20 kHz). cavitation.
I loko o kēia hana, ua noiʻi mākou i ka hiki ke hoʻololi i ke ʻano o nā mea hao austenitic ma o ka hoʻoheheʻe ʻana i ka loko i hoʻoheheʻe ʻia me nā hawewe kani i hana ʻia e ka laser hehee iho. ʻO nā papa kila kila i ʻike ʻia i ka ikaika-modulated laser radiation. No laila, ʻenehana, ua hana ʻia ka mālama ʻana i ka ʻili laser. Akā, inā hana ʻia kēlā ʻano lapaʻau laser ma luna o ka ʻili o kēlā me kēia papa, i ka wā e kūkulu ʻia ai kēlā me kēia papa, e hoʻokō ʻia nā hopena ma ka leo holoʻokoʻa a ma nā ʻāpana i koho ʻia o ka leo.
ʻOiai i ka ultrasonic horn-based ultrasonic therapy, ua puʻunaue ʻia ka ikaika kani ultrasonic o ka hawewe kani kū i loko o ka ʻāpana, ʻoiai ka ikaika o ka ultrasonic i hoʻokomo ʻia i ka laser e pili pono ana i kahi kokoke i kahi e komo ai ka radiation laser. ʻO ka velocity velocity he amplitude kiʻekiʻe ma luna o ka ʻili luna holoʻokoʻa o ka ʻāpana. ʻAʻole hiki i ke kani ke kani i loko o ka wai hoʻoheheʻe holoʻokoʻa ma mua o 0.1% o ka nui o ke kaomi i hana ʻia e ke poʻo kuʻi, no ka mea, ʻo ka hawewe o nā hawewe kani ultrasonic me ke alapine o 20 kHz i ke kila kila he \(\sim 0.3~\text {m}\), a me ka ʻO ka hohonu o ka ultrasound ma mua o ka {3}, ka mea maʻamau ka hopena o ka ultrasound. liʻiliʻi paha ka cavitation.
Pono e hoʻomaopopo ʻia ʻo ka hoʻohana ʻana i ka radiation laser i hoʻololi ʻia i ka hoʻopaʻa ʻana i ka metala laser he wahi ikaika o ka noiʻi35,36,37,38.
ʻO nā hopena wela o ka hoʻoheheʻe ʻia ʻana o ka laser ma ka waena ke kumu no ka aneane pau ʻana i nā ʻenehana laser 39, 40, e like me ke ʻoki ʻana i ka 41, ka hoʻoheheʻe ʻana, ka paʻakikī, ka wili ʻana 42, ka hoʻomaʻemaʻe ʻili, ka hui ʻana o ka ʻili, ka polishing 43, etc.
Pono e hoʻomaopopo ʻia ʻo kēlā me kēia hana non-stationary ma luna o ka medium, me ka lasing hana ma ka absorbing medium, e hopena i ka excitation o nā hawewe acoustic i loko o ia me ka ʻoi aʻe a emi ʻole ka pono.Initially, ka manaʻo nui i ka laser excitation o nā hawewe i loko o ka wai a me nā ʻano hana hoʻohiwahiwa wela o ke kani (thermal expansion, evaporation, volume change during phase transition), 47, 99graph, 47, etc. Hāʻawi ʻo 1, 52 i nā loiloi kumu o kēia kaʻina hana a me kāna mau noi kūpono.
Ua kūkākūkā ʻia kēia mau pilikia ma nā ʻaha kūkā like ʻole, a ua hoʻokumu ʻia ka laser excitation o ka ultrasound i nā noi ʻelua o ka ʻenehana laser53 a me ka lāʻau lapaʻau54. No laila, hiki ke manaʻo ʻia ua hoʻokumu ʻia ka manaʻo kumu o ke kaʻina hana e hana ai nā kukui laser pulsed ma kahi mea absorbing.
ʻO ka hopena o nā hawewe haʻalulu i hana ʻia e ka laser ke kumu o ka laser shock peening57,58,59, ka mea i hoʻohana ʻia no ka mālama ʻana i ka ʻili o nā ʻāpana i hana ʻia i hoʻohui ʻia 60. Eia naʻe, ʻoi aku ka maikaʻi o ka hoʻoikaika ʻana i ka laser ma nā pulses laser nanosecond a me nā wahi i hoʻouka ʻia (e laʻa, me kahi papa wai)59 no ka mea, hoʻonui ka hoʻouka ʻana o ka mīkini.
Ua hana ʻia nā hoʻokolohua no ka noiʻi ʻana i nā hopena kūpono o nā kahua kino like ʻole ma ka microstructure o nā mea paʻa. Ma muli o ka hui pū ʻana o nā kānana mānoanoa kūʻokoʻa, ʻokoʻa ka ikehu pulse ma ka pahu hopu mai \(E_L \sim 20~\text {mJ}\) a i \(E_L \sim 100~\text {mJ}\). ) ua hoʻohana ʻia e hoʻoholo i ka hanana a ʻike ʻia mai ka pahu hopu, a ʻelua mau mika mana (photodiodes me nā manawa pane pōkole \(<10~\text {ns}\)) e hoʻoholo ai i ka hanana a me ka mana optical. ns (Ka uhi ʻana i ka antireflection ma \(1.06 \upmu \text {m}\), ka lōʻihi o ke kiko \(160~\text {mm}\)) a me ka pūhaka kaola ma ka ʻili huli 60– \(100~\upmu\text {m}\).
Kiʻi hoʻolālā hana o ka hoʻonohonoho hoʻokolohua: 1—laser;2—ke kukui laser;3— kānana mānoanoa kūʻokoʻa;4—photodiode i hui pū ʻia;5—mea hoʻokaʻawale kaola;6—diaphragm;7—calorimeter o ka kukuna hanana;8 - calorimeter o ke kukui i ʻike ʻia;9 - ka mika mana kukuna hanana;10 - ʻike ʻia ka mika mana kukuna;11 - ka nānā ʻana i ka lens;12 - aniani;13 - hāpana;14 - transducer piezoelectric broadband;15 - 2D mea hoʻololi;16 - hoʻonohonoho i ka microcontroller;17 - hui hoʻonohonoho;18 - ʻōnaehana kiʻi kikohoʻe lehulehu me nā helu hoʻohālike like ʻole;19 – kamepiula pilikino.
Hoʻokō ʻia ka mālama ʻana i ka ultrasonic penei.No laila, ʻo ka lōʻihi o ka pulse laser he \(\tau _L \sim 150~\upmu \text {s}\), i loaʻa i nā lōʻihi he nui ma kahi o \(1.5~\upmu \text {s } \) kēlā me kēia. ʻO keʻano kino o ka pulse laser a me kona spectrum he enveloppe haʻahaʻa a me kahi kiʻekiʻe-frequency modulation o ~, me ka awelika o ka helu 7 MHz, me ka awelika figure o ~, me ka awelika o ka 2 MHz. .- Hāʻawi ka enveloppe alapine i ka hoʻomehana a me ka hoʻoheheʻe ʻana a me ka hoʻoheheʻe ʻana o ka mea, ʻoiai ke hāʻawi nei ka mea alapine kiʻekiʻe i nā vibrations ultrasonic ma muli o ka hopena photoacoustic.Mai ka \(7~\text {kHz}\) a i ka \ (2~\text {MHz}\), a o ke alapine waena he \(~ 0.7~\text {MHz}\).Acoustic pulses ma muli o ka photoacoustic hopena ua hoʻopaʻa 'ia me ka broadband piezoelectric transducers i hanaia me ka polyvinylidene fluoride films. he laser holo manuahi.
ʻO ka māhele manawa o ka laser pulse ikaika (a) a me ke kani velocity (b) ma ka ʻaoʻao hope o ka hāpana, ka spectra (blue curve) o ka pulse laser hoʻokahi (c) a me ka pulse ultrasound (d) awelika ma luna o 300 laser pulses (ʻulaʻula ʻulaʻula).
Hiki iā mākou ke hoʻokaʻawale i nā ʻāpana haʻahaʻa haʻahaʻa a me nā ʻāpana kiʻekiʻe o ka hoʻomaʻamaʻa acoustic e pili ana i ka envelop haʻahaʻa haʻahaʻa o ka pulse laser a me ka modulation kiʻekiʻe.no laila, ua manaʻo ʻia ka hopena nui o nā ʻāpana ākea kiʻekiʻe o ka hōʻailona acoustic ma ka microstructure.
He paʻakikī nā kaʻina hana kino i ka SLM a hiki i ka manawa like ma nā unahi spatial a me ke kino.
ʻO ka helu ʻana a me ka hoʻoluʻu ʻana a hiki i \(10^6~\text {K}/\text {s}\) /\text{ ma muli o ka hoʻomālamalama laser kūloko me nā mānoanoa mana a hiki i \(10^{13}~\text {W} cm}^2\).
ʻO ka pōʻai hoʻoheheʻe-paʻa ka lōʻihi ma waena o 1 a me \(10~\text {ms}\), e kōkua ana i ka hoʻopaʻa paʻa wikiwiki ʻana o ka wahi hoʻoheheʻe i ka wā hoʻoluʻu.
ʻO ka hoʻomehana wikiwiki ʻana o ka ʻili o ka hāpana i ka hoʻokumu ʻia ʻana o nā koʻikoʻi thermoelastic kiʻekiʻe i ka ʻili o ka ʻili. e hoʻolaha mai ka ʻili a i ka substrate. No ka loaʻa ʻana o ka ʻikepili helu kūpono e pili ana i ke koʻikoʻi kūloko a me ka puʻunaue ʻana, ua hana ʻia kahi hoʻohālikelike mesoscopic o ka pilikia deformation elastic conjugated i ka wela a me ka hoʻoili lehulehu.
ʻO nā hoohalike hoʻomalu o ke kŘkohu he (1) unsteady heat transfer equation kahi thermal conductivity e pili ana i ke kūlana o ka pae (powder, melt, polycrystalline) a me ka mahana, (2) fluctuations in elastic deformation after continuum ablation and thermoelastic expansion equation. The boundary value problem is determined by experimental conditions.The modulated laser cool sample surface is. Ua ho'ākāka 'ia ka s flux ma muli o ka helu 'ana o ke kaomi mahu o ka evaporating mea. Ho'ohana 'ia ka pilina elastoplastic stress-strain kahi e like ai ke ko'iko'i thermoelastic i ka like 'ole o ka mahana.
Hōʻike ka Figure 3 i nā hopena o ka hoʻohālikelike helu o ka ʻāpana hoʻoheheʻe me ka hoʻohana ʻana i ke kumu hoʻohālike makemakika macroscopic. ʻO ke anawaena o ka fusion zone ʻo \(200~\upmu \text {m}\) (\(100~\upmu \text {m}\) radius) a me \(40~\upmu \text {m}\) ka hohonu o ka hōʻike 'ana i ka wela o ka 'ilikai {m}\). \) ma muli o ke kiʻekiʻe intermittent kumu o ka pulse modulation.ʻO ka wela \(V_h\) a me ka hoʻoluʻu \(V_c\) nā helu ma ke kauoha o \(10^7\) a me \(10^6~\ kikokikona {K}/\ kikokikona {s}\), pakahi. Ua kūpono kēia mau waiwai me kā mākou mua analysis64. ili papa, kahi thermal conduction i ka substrate lawa ole e wehe i ka wela. No laila, ma \(t=26~\upmu \text {s}\) ka wela o ka ili kiʻekiʻe e like me \(4800~\text {K}\).
Nā hualoaʻa hoʻohālikelike helu o ka wahi heheʻe o hoʻokahi laser pulse annealing ma 316L sample plate. ʻO ka manawa mai ka hoʻomaka ʻana o ka pulse a hiki i ka hohonu o ka wai hoʻoheheʻe a hiki i ka waiwai kiʻekiʻe ʻo \ (180 ~ \ upmu \ kikokikona {s} \). ʻO ka isotherm \ (T = T_L = 1723 ~ \ kikokikona {K}\) e hōʻike ana i ka palena wai a me ka palena paʻa. ld stress helu 'ia e like me ka hana o ka wela ma ka hope pauku. No laila, i loko o ka domain ma waena o nā isolines elua (isotherms\(T=T_L\) a me isobars\(\sigma =\sigma _V(T)\)), ka paa paʻa i lalo i ka ikaika mechanical haawe , i hiki ke alakai i ka hoʻololi i ka microstructure.
Ua wehewehe hou ʻia kēia hopena ma ka Figure 4a, kahi i hoʻolālā ʻia ai ke kiʻekiʻe o ke kaomi i loko o ka ʻāpana hoʻoheheʻe ʻia ma ke ʻano he hana o ka manawa a me ka mamao mai ka ʻili. Loaʻa i ka lae nā ʻano oscillation like me ka alapine o \(500~\text {kHz}\). ʻO ia ke ʻano o nā hawewe kaomi kani ultrasonic e hana ʻia ma ka ʻili a laila hoʻolaha i loko o ka substrate.
Hōʻike ʻia nā hiʻohiʻona i helu ʻia o ka ʻāpana deformation kokoke i ka ʻāpana heheʻe. ʻO ke koʻikoʻi ma muli o ka laser ablation, a ʻaʻole i ʻike ʻia ke koʻikoʻi thermoelastic ma nā wahi mana no ka mea liʻiliʻi loa ka wahi i hoʻopili ʻia i ka wela.
Loaʻa ka hopena koʻikoʻi o nā pae koʻikoʻi modulated i ka pilina paʻa-wai a ʻo ia paha ke ʻano mana e hoʻokele ai i ke ala paʻa. 0 a me \(800~\upmu \text {m}\) ma muli o ka manawa koke.
No laila, ʻo ka modulation paʻakikī o ka pulsed laser annealing alakaʻi i ka hopena ultrasonic. He ʻokoʻa ke ala koho microstructure inā hoʻohālikelike ʻia me ka SLM me ka loaʻa ʻole o ka ultrasonic. hiki ke hoʻolālā i ka pulse modulation-induced ultrasound-driven SLM prototype. I kēia hihia, hiki ke kāpae ʻia ka piezoelectric inductor 26 i hoʻohana ʻia ma nā wahi ʻē aʻe.
(a) Pumi ma ke ano he hana o ka manawa, i heluia ma na mamao like ole mai ka ili 0, 20 a me \(40~\upmu \text {m}\) ma ke axis of symmetry.(b) Kaumaha o Von Mises pili i ka manawa i heluia i loko o ka matrix pa'a ma kahi mamao 70, 120 a me \(170~\upmu \text {m}\) mai ka la'ana ili.
Ua hana ʻia nā hoʻokolohua ma luna o nā pā kila kila AISI 321H me nā ana \(20\times 20\times 5~\text {mm}\). ʻO ka mea i hana ʻia no ka hoʻomaʻemaʻe ʻana i ka palaoa. Ma nā hihia āpau, ua sonicated ka ʻāpana remelted, ma muli o ka ʻāpana oscillatory o ka radiation laser. ʻO kēia ka hopena ma mua o 5-fold ka hoʻemi ʻana i ka awelika o ka palaoa.
Nā ʻāpana liʻiliʻi (a,d,g,j) a me (b,e,h,k) - microstructure o nā ʻāpana hoʻoheheʻe laser, nā subplots (c,f,i,l) - ka māhele ʻāpana o nā hua kala.Hōʻike ka malu i nā ʻāpana i hoʻohana ʻia no ka helu ʻana i ka histogram. Ua pili nā kala me nā ʻāpana palaoa (e ʻike i ka pahu kala ma ka piko o ka histogram. ʻO nā subplots (ac) pili i ke kila kila kila ʻole, a me nā subplots (df), (gi), (jl) e pili ana i nā remelts 1, 3 a me 5.
No ka mea, ʻaʻole e loli ka ikaika o ka pulse laser ma waena o nā hala ma hope, ua like ka hohonu o ka wahi i hoʻoheheʻe ʻia. No laila, "uhi" ke kahawai ma hope i ka mea ma mua.
ʻO ka hoʻomaʻamaʻa ʻana i ka palaoa ma muli o ka hoʻomaloʻo wikiwiki ʻana o ka punawai hoʻoheheʻe ʻia. ma ke ʻano holo manuahi. Akā naʻe, ua ʻike ʻia kahi ʻano columnar maʻamau.
ʻO ka microstructure o ka māhele hoʻoheheʻe laser o kahi laser nalu mau (300 W ka mana mau, 200 mm/s scan wikiwiki, AISI 321H kila kila).
(a) Microstructure a me (b) electron backscatter diffraction kiʻi o ka laser melting zone o vacuum hoʻomau nalu laser (ka mana mau 100 W, scanning speed 200 mm/s, AISI 316L stainless steel) \ (\ sim 2~\ kikokikona {mbar }\).
No laila, ua maopopo i ka paʻakikī modulation o ka laser pulse ikaika loa i ka hopena microstructure.We manaʻoʻiʻo i keia hopena he mechanical i loko o ke ano a hiki ma muli o ka hanauna o kani ultrasonic vibrations propagating mai ka irradiated ili o ka hehee hohonu i loko o ka hāpana. Ti-6Al-4V huila 26 a me kuhiliʻole kila 34 ka hopena o. Ka mea hiki mechanical ua speculated e like me follows.Intense ultrasound hiki ke kumu acoustic cavitation, e like me ka hoike ana ma ultrafast in situ synchrotron X-ray imaging.The collapse of the cavitation bubbles in turn generates shock waves in the molten material, its front pressures reaches about \ 6 text hawewe. e paipai i ka hookumu ana i na nuclei solid-phase ko'iko'i i loko o ka wai nui, me ka hoopau ana i ke ano o ka palaoa columnar ma'amau o ka hana hookui papa-a-papa.
Maʻaneʻi, ke noi aku nei mākou i kekahi hana ʻē aʻe e pili ana i ka hoʻololi ʻana i ka hoʻololi ʻana e ka sonication ikaika. ʻO ka mea ma hope o ka solidification aia ma kahi wela kiʻekiʻe kokoke i ka helu heheʻe a loaʻa kahi haʻahaʻa haʻahaʻa haʻahaʻa. 8) No laila, e ho'āʻo i ke kuhiakau, ua hana mākou i ka molecular dynamics (MD) simulations o ka Fe-Cr-Ni haku mele like me AISI 316 L kila i mea e loiloi ai i ka hana koʻikoʻi e pili ana i ka helu heheʻe. Hoʻohālikelike (EAM) mai ka 74.MD simulations i hana ʻia me ka hoʻohana ʻana i nā code LAMMPS 75,76. E paʻi ʻia nā kikoʻī o ka simulation MD ma kahi ʻē.
Hāʻawi i ke koʻikoʻi no ka AISI grade 316 austenitic stainless steel a me ka hoʻokumu ʻana i ke ʻano hoʻohālike me ka mahana no nā simulations MD. ʻO nā ana hoʻokolohua mai nā kuhikuhi: (a) 77, (b) 78, (c) 79, (d) 80, (e) 81. e pili ana i. -scale MD simulation hualoaʻa i loko o keia haʻawina e denoted e like me \(\vartriangleleft\) no ka hemahema-noa palena ole a me ka \(\vartriangleright\) no ka palena o ka palaoa me ka noonoo ana i ka awelika o ka palaoa ma o ka Hall-Petch pili Dimensions\(d = 50~\upmu \text {m}\).
Hiki ke ʻike ʻia ma ka \(T>1500~\text {K}\) ke hāʻule iho nei ke koʻikoʻi o ka hua ma lalo o \(40~\text {MPa}\).Ma kekahi ʻaoʻao, wānana nā manaʻo e ʻoi aku ka nui o ka ultrasonic amplitude i hana ʻia e ka laser i \(40~\text {MPa}\) (e nānā Fig. 4b), ʻo ia ka lawa no ka hoʻoulu ʻana i ka plastic solid flow.
Ua hoʻāʻo ʻia ka hoʻokumu ʻana o ka microstructure o 12Cr18Ni10Ti (AISI 321H) austenitic stainless steel i ka wā SLM me ka hoʻohana ʻana i kahi kumu laser pulsed paʻakikī.
Ua ʻike ʻia ka hōʻemi ʻana o ka nui o ka palaoa i ka wahi hoʻoheheʻe laser ma muli o ka hoʻoheheʻe ʻana o ka laser ma hope o 1, 3 a i ʻole 5 mau hala.
Hōʻike ka hoʻohālike macroscopic i ka nui i manaʻo ʻia o ka ʻāina kahi e hoʻopilikia maikaʻi ai ka hoʻololi ʻana o ke kani ultrasonic i ka mua solidification a hiki i \(1~\text {mm}\).
Hōʻike ke kumu hoʻohālike microscopic MD i ka hoʻemi nui ʻana o ka ikaika hua o AISI 316 austenitic stainless steel i \(40~\text {MPa}\) kokoke i ka helu heheʻe.
Hōʻike nā hopena i loaʻa i kahi ala no ka hoʻomalu ʻana i ka microstructure o nā mea me ka hoʻohana ʻana i ka hoʻoili laser modulated paʻakikī a hiki ke lilo i kumu no ka hana ʻana i nā hoʻololi hou o ka ʻenehana SLM pulsed.
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