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A na-atụ aro usoro ọhụrụ dabere na agbaze laser ahọpụtara iji chịkwaa obere nhazi nke ngwaahịa na usoro mmepụta. Usoro a dabere na mmepụta nke ebili mmiri ultrasonic dị elu na ọdọ mmiri gbazere agbaze site na radieshon laser dị mgbagwoju anya nke nwere ike ịgbanwe. Ọmụmụ ihe nnwale na ihe ngosi ọnụọgụgụ na-egosi na usoro njikwa a nwere ike ime nke ọma na teknụzụ ma enwere ike itinye ya n'ime imewe nke igwe agbaze laser nke oge a.
Mmepụta mgbakwunye (AM) nke akụkụ ndị dị mgbagwoju anya etoola nke ukwuu n'ime iri afọ ndị na-adịbeghị anya. Agbanyeghị, n'agbanyeghị ụdị usoro mmepụta mgbakwunye, gụnyere nhọrọ laser agbaze (SLM)1,2,3, nkwụnye ígwè laser kpọmkwem4,5,6, agbaze ígwè elektrọn7,8 na ndị ọzọ9,10, Akụkụ ndị ahụ nwere ike inwe nkwarụ. Nke a bụ isi n'ihi njirimara kpọmkwem nke usoro ịgbaze ọdọ mmiri agbaze nke jikọtara ya na nnukwu mgbaze okpomọkụ, oke oyi dị elu, na mgbagwoju anya nke usoro ikpo ọkụ na agbaze na ihe mgbaze11, nke na-eduga na uto ọka epitaxial na nnukwu porosity12,13. Nsonaazụ na-egosi na , ọ dị mkpa ijikwa mgbaze okpomọkụ, ọnụego oyi, na nhazi alloy, ma ọ bụ tinye ihe mberede anụ ahụ ọzọ site na mpaghara mpụga nke ihe dị iche iche (dịka ọmụmaatụ, ultrasound) iji nweta nhazi ọka dị mma.
Ọtụtụ akwụkwọ na-ekwu maka mmetụta nke ọgwụgwọ ịma jijiji na usoro siri ike na usoro nkedo ọdịnala14,15. Agbanyeghị, itinye ubi mpụga na nnukwu agbaze anaghị emepụta obere nhazi ihe achọrọ. Ọ bụrụ na olu nke usoro mmiri mmiri dị obere, ọnọdụ ahụ na-agbanwe nke ukwuu. N'okwu a, ubi mpụga na-emetụta usoro siri ike nke ukwuu. A tụlere mmetụta elektrọnik n'oge ubi acoustic siri ike16,17,18,19,20,21,22,23,24,25,26,27, arc stiming28 na oscillation29, pulsed plasma arcs30,31 na ụzọ ndị ọzọ32. Jikọọ na substrate site na iji isi iyi ultrasound dị elu (na 20 kHz). A na-akọwapụta mmezi ọka nke ultrasound kpatara na mpaghara subcooling mụbara n'ihi mbelata okpomọkụ na mmụba ultrasound iji mepụta kristal ọhụrụ site na cavitation.
N'ọrụ a, anyị nyochara ohere nke ịgbanwe usoro ọka nke ígwè anaghị agba nchara austenitic site n'ịkpọsa ọdọ mmiri ahụ gbazere agbaze site na iji ụda olu nke laser agbaze n'onwe ya mepụtara. Mgbanwe ike nke ihe merenụ na radieshon laser na ihe na-amịkọrọ ìhè na-eme ka e nwee ebili mmiri ultrasonic, nke na-agbanwe obere nhazi nke ihe ahụ. Enwere ike itinye mgbanwe ike a nke radieshon laser n'ime ngwa nbipute SLM 3D dị ugbu a ngwa ngwa. Emere nnwale ndị dị n'ọrụ a na efere ígwè anaghị agba nchara nke elu ha gosipụtara radieshon laser nke na-agbanwe ike. Ya mere, n'ụzọ teknụzụ, a na-eme ọgwụgwọ elu laser. Agbanyeghị, ọ bụrụ na emee ọgwụgwọ laser dị otú ahụ n'elu oyi akwa ọ bụla, n'oge nhazi oyi akwa site na oyi akwa, a na-enweta mmetụta na olu dum ma ọ bụ na akụkụ ahọpụtara nke olu ahụ. N'ikwu ya n'ụzọ ọzọ, ọ bụrụ na e wuru akụkụ ahụ oyi akwa site na oyi akwa, ọgwụgwọ elu laser nke oyi akwa ọ bụla hà nhata "ọgwụgwọ olu laser".
Ebe ọ bụ na ọgwụgwọ ultrasonic dabere na mpi ultrasonic, ike ultrasonic nke ụda kwụ ọtọ na-ekesa n'ime akụkụ ahụ niile, ebe ike ultrasonic nke laser kpatara na-etinye uche nke ukwuu nso ebe a na-amịkọrọ radieshon laser. Iji sonotrode na igwe ntụ ntụ SLM dị mgbagwoju anya n'ihi na elu elu nke akwa ntụ ntụ nke a na-ekpughere na radieshon laser kwesịrị ịnọgide na-adịgide. Na mgbakwunye, enweghị nrụgide mekaniki na elu elu nke akụkụ ahụ. Ya mere, nrụgide acoustic dị nso na efu na ọsọ nke ihe ahụ nwere oke kachasị n'elu elu elu nke akụkụ ahụ dum. Nrụgide ụda dị n'ime ọdọ mmiri gbazere agbaze niile enweghị ike ịgafe 0.1% nke nrụgide kachasị nke isi ịgbado ọkụ na-emepụta, n'ihi na ogologo ebili mmiri ultrasonic nwere ugboro 20 kHz na ígwè anaghị agba nchara bụ \(\sim 0.3~\text {m}\), na Omimi na-adịkarị obere karịa \(\sim 0.3~\text {mm}\).Ya mere, mmetụta nke ultrasound na cavitation nwere ike ịdị obere.
E kwesịrị ịmara na ojiji nke radieshon laser nke nwere ike ịgbanwe n'ime ihe nkwụnye ígwè laser kpọmkwem bụ ihe a na-eme nnyocha a35,36,37,38.
Mmetụta okpomọkụ nke ihe mberede radieshon laser na ihe na-eme bụ ntọala maka ihe fọrọ nke nta ka ọ bụrụ usoro laser niile 39, 40 maka nhazi ihe, dị ka ịkpụcha ihe41, ịgbado ọkụ, ime ka ọ sie ike, igwu mmiri42, nhicha elu, itinye ihe n'elu, ime ka ihe dị ọcha n'elu43, wdg. Ihe mepụtara laser ahụ kpaliri mmepe ọhụrụ na usoro nhazi ihe, a chịkọtawokwa nsonaazụ mbụ na ọtụtụ nyocha na monographs44,45,46.
E kwesịrị ịmara na ihe ọ bụla na-anaghị eguzo na ihe na-eme, gụnyere ihe na-eme ka ihe na-amịkọrọ mmiri na-amịkọrọ mmiri, na-eme ka ebili mmiri dị n'ime ya na-arụ ọrụ nke ọma ma ọ bụ na-adịghị mma. Ná mmalite, isi ihe dị na ya bụ mkpali laser nke ebili mmiri na mmiri mmiri na usoro mkpali okpomọkụ dị iche iche nke ụda (mgbasawanye okpomọkụ, evaporation, mgbanwe olu n'oge mgbanwe nkebi, mkpụmkpụ, wdg.) 47, 48, 49. Ọtụtụ akwụkwọ ọgụgụ50, 51, 52 na-enye nyocha echiche nke usoro a na ojiji ya nwere ike ime.
E mechara tụlee okwu ndị a n'ọtụtụ nnọkọ dị iche iche, mkpali laser nke ultrasound nwekwara ojiji na ngwa ụlọ ọrụ mmepụta ihe nke teknụzụ laser53 na ọgwụ54. Ya mere, enwere ike ịtụle na echiche bụ isi nke usoro nke ọkụ laser pulsed na-arụ ọrụ na ihe na-amịkọrọ ihe etolitela. A na-eji nyocha laser ultrasonic maka nchọpụta ntụpọ nke ihe atụ SLM mepụtara55,56.
Mmetụta nke ebili mmiri ujo nke laser na-akpata na ihe bụ ntọala nke ujo laser peening57,58,59, nke a na-ejikwa maka ọgwụgwọ elu nke akụkụ ndị e mepụtara na mgbakwunye60. Agbanyeghị, ike ujo laser na-arụ ọrụ nke ọma na pulses laser nanosecond na elu ndị e ji igwe rụọ (dịka ọmụmaatụ, na oyi akwa mmiri)59 n'ihi na ibu igwe na-eme ka nrụgide kachasị elu dịkwuo elu.
E mere nnwale iji chọpụta mmetụta nke ubi anụ ahụ dị iche iche nwere ike inwe na obere nhazi nke ihe ndị siri ike. E gosiri eserese ọrụ nke ntọala nnwale ahụ na Foto 1. E jiri laser siri ike nke Nd:YAG nke na-arụ ọrụ na ọnọdụ ịgba ọsọ n'efu (oge pulse \(\tau _L \sim 150~\upmu \text {s}\ )) mee ihe. A na-agafe pulse laser ọ bụla site na usoro nzacha njupụta na-anọpụ iche na sistemụ efere nkewa beam. Dabere na njikọta nke nzacha njupụta na-anọpụ iche, ike pulse na ihe mgbaru ọsọ dị iche site na \(E_L \sim 20~\text {mJ}\) ruo \(E_L \sim 100~\text {mJ}\) . A na-enye bul laser nke na-egosipụta site na bul splitter na photodiode maka inweta data n'otu oge, a na-ejikwa calorimeter abụọ (photodiodes nwere oge nzaghachi ogologo gafere \(1~\text {ms}\)) iji chọpụta ihe merenụ na ma gosipụta site na ihe mgbaru ọsọ ahụ, yana mita ike abụọ (photodiodes nwere nzaghachi dị mkpirikpi ugboro\(<10~\text {ns}\)) iji chọpụta ihe merenụ na ike anya e gosipụtara. E mere ka calorimita na mita ike dị iche iche nye ụkpụrụ na nkeji zuru oke site na iji ihe nchọpụta thermopile Gentec-EO XLP12-3S-H2-D0 na enyo dielectric nke etinyere na ebe nlele ahụ. Lekwasị anya na oghere ahụ n'ihe mgbaru ọsọ ahụ site na iji lenzi (mkpuchi Antireflection na \(1.06 \upmu \text {m}\), ogologo focal \(160~\text {mm}\)) na úkwù ogwe aka na elu ihe mgbaru ọsọ 60– \(100~\upmu\text {m}\).
Ihe osise eserese ọrụ nke nhazi nnwale: 1—laser; 2—laser beam; 3—nzacha njupụta na-anọpụ iche; 4—fotodiode emekọtara ọnụ; 5—beam splitter; 6—diaphragm; 7—calorimeter nke ihe merenụ; 8 – calorimeter nke ihe ahụ e gosipụtara; 9 – mita ike nke ihe merenụ; 10 – mita ike nke ihe ahụ e gosipụtara; 11 – lensị na-elekwasị anya; 12 – enyo; 13 – ihe nlele; 14 – transducer piezoelectric broadband; 15 – 2D converter; 16 – microcontroller nhazi; 17 – nkeji mmekọrịta; 18 – sistemụ nnweta dijitalụ ọtụtụ ọwa nwere ọnụego nlele dị iche iche; 19 – kọmputa nkeonwe.
A na-eme ọgwụgwọ ultrasonic dịka ndị a. Laser ahụ na-arụ ọrụ n'ụdị na-agba ọsọ n'efu; ya mere, oge nke laser pulse bụ \(\tau _L \sim 150~\upmu \text {s}\), nke nwere ọtụtụ oge nke ihe dị ka \(1.5~\upmu \text {s} \) nke ọ bụla. Ọdịdị oge nke laser pulse na ụdị ya nwere obere envelopu na mgbanwe ugboro ugboro dị elu, yana nkezi ugboro ole dị ihe dị ka \(0.7~\text {MHz}\), dịka egosiri na Foto 2.- Envelopu ugboro ugboro na-enye ihe na-ekpo ọkụ na agbaze na evaporation nke ihe ahụ, ebe akụkụ ugboro ugboro dị elu na-enye mkpọtụ ultrasonic n'ihi mmetụta fotoacoustic. Ụdị ebili mmiri nke ultrasonic pulse nke laser mepụtara na-adaberekarị n'ụdị oge nke ike laser pulse. Ọ dị site na \(7~\text {kHz}\) ruo \ (2~\text {MHz}\), ugboro etiti ahụ bụkwa \(~ 0.7~\text {MHz}\). E jiri transducers piezoelectric broadband nke e ji ihe nkiri polyvinylidene fluoride mee dekọọ mkpali acoustic n'ihi mmetụta fotoacoustic. E gosiri ụdị ebili mmiri e dekọrọ na spectrum ya na Foto nke 2. E kwesịrị ịmara na ọdịdị nke pulses laser bụ ihe a na-ahụkarị na laser mode na-agba ọsọ n'efu.
Nkesa oge nke ike mkpali laser (a) na ọsọ ụda n'azụ ihe nlele ahụ (b), spectra nke laser pulse (c) na ultrasonic pulse (d) nkezi ihe karịrị 300 laser pulses (uhie curve) maka otu laser pulse (blue curve).
Anyị nwere ike ịmata nke ọma ihe dị iche n'etiti obere ugboro na oke ugboro nke ọgwụgwọ acoustic nke dabara na obere ugboro nke laser pulse na nnukwu ugboro, n'otu n'otu. Ogologo ebili mmiri nke acoustic nke envelopu laser pulse na-emepụta gafere \(40~\text {cm}\); ya mere, a na-atụ anya mmetụta bụ isi nke ihe dị iche iche nke broadband elu ugboro nke mgbaàmà acoustic na obere nhazi.
Usoro anụ ahụ dị na SLM dị mgbagwoju anya ma na-eme n'otu oge na nha dị iche iche nke oghere na oge. Ya mere, usoro dị iche iche dabara adaba maka nyocha echiche nke SLM. Ụdị mgbakọ na mwepụ kwesịrị ịbụ nke anụ ahụ na mbụ. Enwere ike ịkọwa usoro na thermophysics nke multiphase ọkara "mgbaze mmiri siri ike" nke na-emekọ ihe na ikuku gas na-adịghị arụ ọrụ nke ọma. Àgwà nke ibu okpomọkụ ihe dị na SLM bụ ndị a.
Ọnụego ọkụ na oyi ruo na \(10^6~\text {K}/\text {s}\) /\text{ n'ihi radieshon laser mpaghara yana njupụta ike ruo \(10^{13}~\text {W} cm}^2\).
Usoro ịgbaze na ịgbaze na-adịru n'etiti 1 na \(10~\text {ms}\), nke na-eme ka mpaghara ịgbaze na-agbaze ngwa ngwa n'oge oyi.
Okpomọkụ ngwa ngwa nke elu ihe nlele na-eme ka nrụgide thermoelastic dị elu na oyi akwa elu. Akụkụ zuru oke (ruo 20%) nke oyi akwa ntụ ntụ na-apụ n'anya nke ukwuu63, nke na-ebute ibu nrụgide ọzọ n'elu nzaghachị maka iwepụ laser. N'ihi ya, nsogbu ahụ na-agbagọ nke ukwuu na geometry akụkụ ahụ, ọkachasị nso nkwado na ihe owuwu dị gịrịgịrị. Oke okpomọkụ dị elu na mwepụ laser pulsed na-ebute mmepụta nke ebili mmiri nrụgide ultrasonic nke na-agbasa site na elu ruo na substrate. Iji nweta data ziri ezi gbasara nrụgide mpaghara na nkesa nrụgide, a na-eme ihe ngosi mesoscopic nke nsogbu mgbanwe elastic jikọtara na okpomọkụ na nnyefe oke.
Usoro nhazi nke ihe nlereanya ahụ gụnyere (1) usoro nhazi okpomọkụ na-adịghị akwụsi ike ebe njikwa okpomọkụ na-adabere na ọnọdụ nkebi (ntụ ntụ, agbaze, polycrystalline) na okpomọkụ, (2) mgbanwe na mgbanwe elastic mgbe njedebe continuum na nhazi mgbasa thermoelastic. A na-ekpebi nsogbu uru ókè site na ọnọdụ nnwale. A na-akọwa flux laser modulated na elu ihe nlele. Convective cooling gụnyere mgbanwe okpomọkụ na-eduzi na flux evaporative. A na-akọwa flux oke dabere na ngụkọ nke nrụgide vapor juru eju nke ihe na-ekupụ. A na-eji mmekọrịta nrụgide elastoplastic ebe nrụgide thermoelastic dabara na ọdịiche okpomọkụ. Maka ike aha \(300~\text {W}\), ugboro ugboro \(10^5~\text {Hz}\), coefficient intermittent 100 na \(200~\upmu \text {m}\ ) nke dayameta ọkụ dị irè.
Foto nke 3 na-egosi nsonaazụ nke ihe nlereanya ọnụọgụgụ nke mpaghara agbazere agbaze site na iji ụdị mgbakọ na mwepụ macroscopic. Dayameta nke mpaghara njikọ bụ \(200~\upmu \text {m}\) (\(100~\upmu \text {m}\) radius) na \(40~\upmu \text {m}\) omimi. Nsonaazụ ihe nlereanya ahụ na-egosi na okpomọkụ elu na-agbanwe n'ógbè ahụ ka oge dị ka \(100~\text {K}\) n'ihi nnukwu ihe na-egbochi mgbanwe pulse. Ọnụego okpomọkụ \(V_h\) na oyi \(V_c\) dị na usoro \(10^7\) na \(10^6~\text {K}/\text {s}\), n'otu n'otu. Ụkpụrụ ndị a kwekọrọ na nyocha anyị gara aga64. Usoro nke oke ọdịiche dị n'etiti \(V_h\) na \(V_c\) na-ebute oke ọkụ ngwa ngwa nke oyi akwa elu, ebe ikuku okpomọkụ na substrate ezughị iji wepụ okpomọkụ. Ya mere, na \(t=26~\upmu \text {s}\) okpomọkụ elu elu dị elu ruo \(4800~\text {K}\). Mmiri siri ike nke ihe ahụ nwere ike ime ka elu ihe nlele ahụ nwee nrụgide dị ukwuu ma gbapụ.
Nsonaazụ ngụkọ nke mpaghara agbaze nke otu laser pulse annealing na efere ihe nlele 316L. Oge site na mmalite nke pulse ruo omimi nke ọdọ mmiri gbazere agbaze na-eru uru kachasị bụ \(180~\upmu\text {s}\).Isotherm\(T = T_L = 1723~\text {K}\) na-anọchite anya ókè dị n'etiti usoro mmiri mmiri na nke siri ike.Isobars (ahịrị odo) kwekọrọ na nrụgide mmepụta nke a gbakọrọ dị ka ọrụ nke okpomọkụ na ngalaba na-esote.Ya mere, na ngalaba dị n'etiti isolines abụọ (isotherms\(T=T_L\) na isobars\(\sigma =\sigma _V(T)\)), usoro siri ike na-etinye ibu siri ike n'ọrụ, nke nwere ike ibute mgbanwe na obere nhazi.
A kọwakwuru mmetụta a na Foto 4a, ebe a na-ese ọkwa nrụgide dị na mpaghara agbaze dị ka ọrụ nke oge na anya site na elu. Nke mbụ, omume nrụgide metụtara mgbanwe nke ike mkpali laser akọwara na Foto 2 n'elu. A hụrụ nrụgide kachasị elu \text{s}\) nke ihe dị ka \(10~\text {MPa}\) na ihe dị ka \(t=26~\upmu). Nke abụọ, mgbanwe nke nrụgide mpaghara na ebe njikwa nwere otu njirimara oscillation dị ka ugboro nke \(500~\text {kHz}\). Nke a pụtara na a na-emepụta ebili mmiri nrụgide ultrasonic n'elu wee gbasaa na substrate.
E gosiri njirimara agbakọrọ nke mpaghara mgbanwe dị nso na mpaghara agbaze na Fig. 4b. Mbelata laser na nrụgide thermoelastic na-emepụta ebili mmiri mgbanwe elastic nke na-agbasa n'ime substrate. Dịka a pụrụ ịhụ site na eserese ahụ, enwere usoro abụọ nke mmepụta nrụgide. N'oge mbụ nke \(t < 40~\upmu \text {s}\), nrụgide Mises na-arị elu ruo \(8~\text {MPa}\) yana mgbanwe yiri nrụgide elu. Nrụgide a na-eme n'ihi mwepụ laser, a hụghịkwa nrụgide thermoelastic na isi njikwa n'ihi na mpaghara mbụ metụtara okpomọkụ dị obere. Mgbe a gbasasịrị okpomọkụ n'ime substrate ahụ, isi njikwa na-emepụta nrụgide thermoelastic dị elu karịa \(40~\text {MPa}\).
Ọkwa nrụgide e nwetara nwere mmetụta dị ukwuu na njikọ siri ike na mmiri mmiri ma nwee ike ịbụ usoro njikwa na-achịkwa ụzọ siri ike. Nha nke mpaghara mgbanwe ahụ karịrị nke mpaghara ịgbaze okpukpu abụọ ruo atọ. Dịka egosiri na Foto nke 3, a na-atụnyere ebe isotherm na-agbaze na ọkwa nrụgide hà nhata nrụgide mmepụta. Nke a pụtara na radieshon laser pulsed na-enye ibu dị elu na mpaghara mpaghara nwere dayameta dị irè n'etiti 300 na \(800~\upmu \text {m}\) dabere na oge ozugbo.
Ya mere, mgbanwe dị mgbagwoju anya nke annealing laser pulsed na-eduga na mmetụta ultrasonic. Ụzọ nhọrọ microstructure dị iche ma ọ bụrụ na e jiri ya tụnyere SLM na-enweghị ibu ultrasonic. Mpaghara ndị na-adịghị akwụsi ike na-eduga na usoro nrụgide na ịgbatị oge n'oge siri ike. Ya mere, nhazi nke ókèala ọka ọhụrụ na ókèala subgrain ga-ekwe omume. Ya mere, enwere ike ịgbanwe njirimara microstructural n'amaghị ama, dịka egosiri n'okpuru. Nkwubi okwu ndị enwetara na-enye ohere ịmepụta ihe nlereanya SLM nke ultrasound na-eduzi site na modulation pulse. N'okwu a, enwere ike iwepụ inductor piezoelectric 26 ejiri ebe ọzọ.
(a) Nrụgide dịka ọrụ nke oge, nke a gbakọrọ n'ebe dị iche iche site na elu 0, 20 na \(40~\upmu \text {m}\) n'akụkụ axis nke symmetry.(b) Von Mises nke dabere na oge na-agbakọ nrụgide na matrix siri ike na anya 70, 120 na \(170~\upmu \text {m}\) site na elu ihe nlele.
E mere nnwale na efere ígwè AISI 321H nke nwere nha \(20\u0020\u0025~\text {mm}\). Mgbe ọ bụla laser pulse gasịrị, efere ahụ na-agagharị \(50~\upmu \text {m}\), úkwù laser ahụ dị n'elu ihe mgbaru ọsọ ahụ dịkwa ihe dị ka \(100~\upmu \text {m}\). A na-eme ihe ruru ngafe ogwe ise na-esote n'otu ụzọ ahụ iji mee ka ihe e ji arụ ọrụ gbanwee maka nhazi ọka. N'ọnọdụ niile, a na-eme ka mpaghara agbazere agbaze ahụ dị nro, dabere na akụkụ oscillatory nke radieshon laser. Nke a na-eme ka mbelata karịa okpukpu ise na nkezi mpaghara ọka. Foto nke 5 na-egosi otu microstructure nke mpaghara agbazere laser si agbanwe na ọnụọgụ nke usoro agbazere agbaze na-esote (gafee).
Mkpụrụ akwụkwọ (a,d,g,j) na (b,e,h,k) – obere nhazi nke mpaghara agbazere na laser, mkpụrụ akwụkwọ (c,f,i,l) – nkesa mpaghara nke mkpụrụ akwụkwọ agba. Ndo na-anọchite anya mkpụrụ akwụkwọ ejiri gbakọọ histogram. Agba na-adakọ na mpaghara ọka (lee ogwe agba dị n'elu histogram. Mkpụrụ akwụkwọ (ac) na-adakọ na ígwè anaghị agba nchara a na-agwọghị, mkpụrụ akwụkwọ (df), (gi), (jl) na-adakọkwa na 1, 3 na 5 remelts.
Ebe ọ bụ na ike mkpali laser anaghị agbanwe n'etiti ngafe ndị na-esote, omimi nke mpaghara agbazere agbaze bụ otu. Ya mere, ọwa na-esote "kpuchiri" nke gara aga kpamkpam. Agbanyeghị, histogram na-egosi na mpaghara ọka nkezi na nke etiti na-ebelata ka ọnụọgụ ngafe na-abawanye. Nke a nwere ike igosi na laser na-arụ ọrụ na substrate kama ịgbaze.
Ndozi ọka nwere ike ịbụ site na ịjụ oyi ngwa ngwa nke ọdọ mmiri gbazere agbaze65. E mere nnwale ọzọ ebe e gosipụtara elu efere ígwè anaghị agba nchara (321H na 316L) na radieshon laser na-aga n'ihu na ikuku (Foto 6) na oghere ikuku (Foto 7). Ike laser nkezi (300 W na 100 W, n'otu n'otu) na omimi ọdọ mmiri gbazere agbaze dị nso na nsonaazụ nnwale nke laser Nd:YAG na ọnọdụ ịgba ọsọ n'efu. Agbanyeghị, a hụrụ usoro kọlụm nkịtị.
Nhazi obere nke mpaghara laser agbazere agbaze nke laser ebili na-aga n'ihu (ike na-adịgide adịgide 300 W, ọsọ nyocha 200 mm/s, ígwè anaghị agba nchara AISI 321H).
(a) Microstructure na (b) onyonyo mgbasa ozi elektrọn nke mpaghara agbazere laser na vacuum nwere laser ebili na-aga n'ihu (ike na-adịgide adịgide 100 W, ọsọ nyocha 200 mm/s, AISI 316L igwe anaghị agba nchara)\ (\sim 2~\text {mbar}\).
Ya mere, a na-egosi nke ọma na mgbanwe mgbagwoju anya nke ike mkpali laser nwere mmetụta dị ukwuu na obere nhazi nke na-esi na ya apụta. Anyị kwenyere na mmetụta a bụ nke igwe ma na-eme n'ihi mmepụta nke ụda ultrasonic na-agbasa site na elu ọkụ nke agbaze miri emi n'ime ihe nlele ahụ. E nwetara nsonaazụ ndị yiri ya na 13, 26, 34, 66, 67 site na iji transducers piezoelectric mpụga na sonotrodes na-enye ultrasound dị elu na ihe dị iche iche gụnyere Ti-6Al-4V alloy 26 na ígwè anaghị agba nchara 34 nsonaazụ nke. A na-atụ anya usoro enwere ike dị ka ndị a. Ultrasound siri ike nwere ike ibute cavitation acoustic, dịka egosiri na ultrafast in situ synchrotron X-ray imaging. Ọdịda nke afụ cavitation na-emepụta ebili mmiri ujo na ihe gbazere agbaze, nke nrụgide ihu ya ruru ihe dị ka \(100~\text {MPa}\)69. Mmiri ujo dị otú ahụ nwere ike ịdị ike iji kwalite nhazi nke nuclei siri ike dị oke mkpa na nnukwu mmiri mmiri, na-emebi usoro ọka kọlụm nkịtị nke mmepụta ihe mgbakwunye oyi akwa site na oyi akwa.
N'ebe a, anyị na-atụ aro usoro ọzọ maka mgbanwe nhazi site na sonication siri ike. Ozugbo emechara sie ike, ihe ahụ dị na okpomọkụ dị elu nso ebe agbaze ma nwee nrụgide mmepụta dị oke ala. Ebili mmiri ultrasonic siri ike nwere ike ime ka mmiri plastik gbanwee usoro ọka nke ihe ọkụ, naanị sie ike. Agbanyeghị, data nnwale a pụrụ ịdabere na ya na ịdabere na okpomọkụ nke nrụgide mmepụta dị na \(T\lesssim 1150~\text {K}\) (lee Foto 8). Ya mere, iji nwalee echiche a, anyị mere ihe ngosi molekul dynamics (MD) nke ihe mejupụtara Fe-Cr-Ni yiri AISI 316 L ígwè iji nyochaa omume nrụgide mmepụta dị nso na ebe agbaze. Iji gbakọọ nrụgide mmepụta, anyị jiri usoro ntụrụndụ MD shear stress nke akọwara na 70, 71, 72, 73. Maka mgbakọta mmekọrịta interatomic, anyị jiri ihe nlereanya Atomic Embedded (EAM) sitere na 74. Emere ihe ngosi MD site na iji koodu LAMMPS 75,76. A ga-ebipụta nkọwa nke ihe ngosi MD ebe ọzọ. Nsonaazụ ngụkọta MD nke E gosiri nrụgide mmepụta dịka ọrụ nke okpomọkụ na Fig. 8 yana data nnwale dị na nyocha ndị ọzọ77,78,79,80,81,82.
Nrụgide maka ígwè anaghị agba nchara nke AISI ọkwa 316 na nhazi ihe nlereanya na okpomọkụ maka ihe nlereanya MD. Ntụle nnwale sitere na ntụaka: (a) 77, (b) 78, (c) 79, (d) 80, (e) 81.refer to.(f)82 bụ ihe nlereanya empirical nke dabere na nrụgide okpomọkụ-mkpụrụ maka nha nrụgide n'ahịrị n'oge nrụpụta mgbakwunye laser. Nsonaazụ nke nnukwu ihe nlereanya MD na ọmụmụ ihe a ka a na-egosi dị ka \(\vartriangleleft\) maka kristal otu na-enweghị ntụpọ na \(\vartriangleright\) maka mkpụrụ nwere njedebe na-atụle nha ọka nkezi site na mmekọrịta Hall-Petch. Nha\(d = 50~\upmu \text {m}\).
A pụrụ ịhụ na na \(T>1500~\text {K}\) nrụgide mmepụta na-agbada n'okpuru \(40~\text {MPa}\). N'aka nke ọzọ, atụmatụ na-ebu amụma na oke ultrasonic nke laser mepụtara gafere \(40~\text {MPa}\) (lee Fig. 4b), nke zuru oke iji kpalite mmiri plastik n'ime ihe ọkụ ahụ siri ike.
E jiri isi iyi laser siri ike nke nwere usoro nhazi obere nke 12Cr18Ni10Ti (AISI 321H) nke austenitic steel n'oge SLM nyochachara ya site na iji usoro nnwale.
A hụrụ mbelata nha ọka na mpaghara agbaze laser n'ihi na laser na-agbaze mgbe niile mgbe 1, 3 ma ọ bụ 5 gafere.
Nlereanya macroscopic na-egosi na nha atụmatụ nke mpaghara ebe mgbanwe ultrasonic nwere ike imetụta ihu siri ike dị mma ruo \(1~\text {mm}\).
Ihe nlereanya MD dị obere na-egosi na ike mmepụta nke ígwè anaghị agba nchara AISI 316 austenitic belatara nke ukwuu ruo \(40~\text {MPa}\) nso ebe agbazere.
Nsonaazụ enwetara na-egosi ụzọ isi chịkwaa obere nhazi nke ihe site na iji nhazi laser dị mgbagwoju anya ma nwee ike ịbụ ntọala maka imepụta mgbanwe ọhụrụ nke usoro SLM pulsed.
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