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Harateganywa uburyo bushya bushingiye ku gushonga kwa laser isanzwe kugira ngo bugenzure imiterere y’ibicuruzwa mu gikorwa cyo gukora. Ubu buryo bushingiye ku gukora imiraba ya ultrasound ifite imbaraga nyinshi mu kidendezi gishongeshejwe hakoreshejwe imirasire ya laser isanzwe ikoreshwa mu buryo bukomeye. Inyigo z’igerageza n’igereranya ry’imibare bigaragaza ko ubu buryo bwo kugenzura bushoboka mu buryo bwa tekiniki kandi bushobora gushyirwa mu buryo bunoze mu gushushanya imashini zigezweho zishongesheje laser isanzwe.
Inyongeramusaruro (AM) y'ibice bifite ishusho ikomeye yariyongereye cyane mu myaka ya vuba aha. Ariko, nubwo hari uburyo butandukanye bwo gukora inyongeramusaruro, harimo gushonga kwa laser (SLM) 1, 2, 3, gushyira ibyuma bya laser mu buryo butaziguye 4, 5, 6, gushonga kwa electron beam 7, 8 n'ibindi 9, 10, Ibice bishobora kuba bifite inenge. Ibi ahanini biterwa n'imiterere yihariye y'uburyo bwo gukomera kw'ikidendezi gishongeshejwe gifitanye isano n'ubushyuhe bwinshi, ubukonje bwinshi, n'ubukana bw'imikorere y'ubushyuhe mu bikoresho bishongesha no gushonga 11, bigatuma ibinyampeke bya epitaxial bikura kandi bigatera porosity ikomeye 12, 13. Ibisubizo bigaragaza ko , ari ngombwa kugenzura ubushyuhe, ubukonje, n'imiterere y'aloyi, cyangwa gushyiramo izindi ngaruka z'umubiri binyuze mu busitani bwo hanze bw'imiterere itandukanye (urugero, ultrasound) kugira ngo hagerwe ku miterere myiza y'ibinyampeke.
Ibitabo byinshi bivuga ku ngaruka zo kuvugururwa kw'imitingito ku buryo bwo gukonjesha mu buryo busanzwe bwo gucukura14,15. Ariko, gukoresha umurima wo hanze mu gushonga mu bwinshi ntibitanga imiterere mito y'ibikoresho byifuzwa. Niba ingano y'igice cy'amazi ari nto, ibintu birahinduka cyane. Muri iki gihe, umurima wo hanze ugira ingaruka zikomeye ku buryo bwo gukonjesha. Ingaruka za electromagnetique zatekerejweho mu gihe cy'imirima ikomeye ya acoustic16,17,18,19,20,21,22,23,24,25,26,27, arc stirling28 na oscillation29, pulsed plasma arcs30,31 n'ubundi buryo32. Shyira kuri substrate ukoresheje isoko ryo hanze rya ultrasound (kuri 20 kHz). Gutunganya ibinyampeke biterwa na ultrasound biterwa no kwiyongera k'agace k'ubukonje bw'ibinyampeke bitewe n'ubushyuhe bugabanuka no kongera ultrasound kugira ngo hakorwe crystallites nshya binyuze mu gucukura.
Muri iki gikorwa, twasesenguye uburyo bwo guhindura imiterere y'ibinyampeke by'ibyuma bita "austenitic stainless steels" binyuze mu gushyira amajwi mu kidendezi gishongeshejwe n'imirasire y'amajwi ituruka kuri laser ubwayo. Guhindura imbaraga z'imirasire ya laser ku buryo bufata urumuri bituma habaho imiraba ya ultrasound, ihindura imiterere y'ibikoresho. Uku guhindura imbaraga kw'imirasire ya laser bishobora gushyirwa mu buryo bworoshye mu mashini zisanzwe za SLM 3D. Igerageza muri iki gikorwa ryakorewe ku byuma bita "stainless steel plates" bifite ubuso bwahuye n'imirasire ya laser ihindagurika. Rero, mu buryo bwa tekiniki, gutunganya ubuso bwa laser birakorwa. Ariko, iyo uburyo nk'ubwo bwo gutunganya bwa laser bukorewe ku buso bwa buri cyiciro, mu gihe cyo kubaka urwego ku rundi, ingaruka ku ngano yose cyangwa ku bice byatoranijwe by'ingano ziragerwaho. Mu yandi magambo, niba igice cyubatswe urwego ku rundi, gutunganya ubuso bwa laser kuri buri urwego bingana na "ubuvuzi bwa laser".
Mu gihe mu buvuzi bwa ultrasound bushingiye ku ihembe rya ultrasound, ingufu za ultrasound z'urusaku ruhagaze zikwirakwizwa mu gice cyose, mu gihe imbaraga za ultrasound ziterwa na laser ziba nyinshi hafi y'aho imirasire ya laser yinjirira. Gukoresha sonotrode mu mashini ihuza ifu ya SLM biragoye kuko ubuso bwo hejuru bw'ifu buhura n'imirasire ya laser bugomba kuguma buhagaze. Byongeye kandi, nta stress ya mekanike iba hejuru y'igice. Kubwibyo, stress ya acoustic iri hafi ya zeru kandi umuvuduko w'uduce ufite amplitude ntarengwa hejuru y'igice cyose. Umuvuduko w'amajwi uri mu kidendezi cyose cyashongeshejwe ntushobora kurenza 0.1% by'umuvuduko ntarengwa uterwa n'umutwe wo gusudira, kuko uburebure bw'imiraba ya ultrasound ifite frequency ya 20 kHz mu cyuma kitagira umugozi ni \(\sim 0.3~\text {m}\), kandi ubujyakuzimu busanzwe buri munsi ya \(\sim 0.3~\text {mm}\). Kubwibyo, ingaruka za ultrasound kuri cavitation zishobora kuba nto.
Icyitonderwa ni uko ikoreshwa ry'imirasire ya laser ikoreshwa mu buryo buhanitse mu gushyira icyuma cya laser mu buryo butaziguye ari ubushakashatsi bukorwa35,36,37,38.
Ingaruka z'ubushyuhe bw'imirasire ya laser ku buryo bw'ikoranabuhanga ni ishingiro ry'ubuhanga bwose bwa laser 39, 40 bwo gutunganya ibikoresho, nko gukata41, gusudira, gukomeresha, gucukura42, gusukura ubuso, gushyiramo alloying ku butaka, gusiga irangi ku butaka43, n'ibindi. Ivumburwa rya laser ryateje imbere iterambere rishya mu buhanga bwo gutunganya ibikoresho, kandi ibisubizo by'ibanze byavuzwe muri make mu isuzuma n'inyandiko nyinshi 44, 45, 46.
Byagombye kumenyekana ko igikorwa icyo ari cyo cyose kidahagaze ku buryo buhamye, harimo no kumara igihe kinini ku buryo bufata, bitera gukurura imiraba y'amajwi muri yo mu buryo bunoze cyangwa buke. Mbere na mbere, intego nyamukuru yari ugukurura imiraba muri lazeri mu mazi n'uburyo butandukanye bwo gukurura amajwi (kwaguka k'ubushyuhe, guhumeka, guhinduka k'ingano mu gihe cy'impinduka, guhindagurika kw'ingufu, nibindi) 47, 48, 49. Monographe nyinshi50, 51, 52 zitanga isesengura ry'ubu buryo n'ikoreshwa ryabwo rishoboka.
Ibi bibazo byaganiriweho mu nama zitandukanye, kandi gushyushya ultrasound hakoreshejwe laser bifite akamaro haba mu ikoranabuhanga rya laser53 ndetse no mu buvuzi54. Kubwibyo, bishobora gufatwa nk'igitekerezo cy'ibanze cy'inzira urumuri rwa laser rukoresha pulsed ku kintu gikurura amazi cyashyizweho. Isuzuma rya ultrasound rya laser rikoreshwa mu gupima inenge z'ingero zakozwe na SLM55,56.
Ingaruka z'imiraba iterwa na laser ku bikoresho ni ishingiro rya laser shock peening57,58,59, ikoreshwa no mu gutunganya ubuso bw'ibice byakozwe mu buryo bw'inyongera60. Ariko, gukomeza laser shock bigira akamaro cyane ku mitsi ya laser ya nanosecond n'ubuso bushyizwemo ibintu (urugero, hamwe n'urwego rw'amazi)59 kuko imbaraga zikoreshwa mu mashini zongera umuvuduko mwinshi.
Igerageza ryakozwe kugira ngo harebwe ingaruka zishobora guterwa n’ibice bitandukanye by’umubiri ku miterere y’ibikoresho bikomeye. Ishusho y’imikorere y’igerageza igaragara ku Ishusho ya 1. Hakoreshejwe laser ya Nd:YAG solid-state ikora mu buryo bwo gukora (igihe cy’impinduka \(\tau _L \sim 150~\upmu \text {s}\ )). Buri pulse ya laser inyuzwa mu ruhererekane rwa filters z’ubucucike butagira aho buhuriye na sisitemu ya splitter plate. Bitewe n’uruvange rwa filters z’ubucucike butagira aho buhuriye, ingufu za pulse ku ntego ziratandukanye kuva kuri \(E_L \sim 20~\text {mJ}\) kugeza kuri \(E_L \sim 100~\text {mJ}\) . Umurabyo wa laser ugaragara uturutse kuri splitter y’ubucucike uhabwa photodiode kugira ngo haboneke amakuru icyarimwe, kandi calorimeter ebyiri (photodiode zifite igihe kirekire cyo gusubiza kirenga \(1~\text {ms}\)) zikoreshwa kugira ngo hamenyekane ibyabaye no kugaragara bivuye ku ntego, na metero ebyiri z’ingufu (photodiode zifite igisubizo gito). times\(<10~\text {ns}\)) kugira ngo hamenyekane aho ibintu byabereye n'ingufu za optique zagaragaye. Kalorimetero na power metters byapimwe kugira ngo bitange agaciro mu bice byuzuye hakoreshejwe thermopile detector Gentec-EO XLP12-3S-H2-D0 n'indorerwamo ya dielectric ishyizwe aho icyitegererezo giherereye. Shyira lumière ku ntego ukoresheje lens (Antireflection coating kuri \(1.06 \upmu \text {m}\), focal length \(160~\text {mm}\)) n'urukenyerero rw'umurambararo ku buso bw'intego 60– \(100~\upmu\text {m}\).
Ishusho y'imikorere y'igerageza: 1—laser; 2—umurabyo wa laser; 3—akayunguruzo k'ubucucike butagira aho bugarukira; 4—photodiode ihuza; 5—umurabyo ugabanya; 6—diaphragm; 7—kalorimetero y'umurabyo w'impanuka; 8 – kalorimetero y'umurabyo ugaragara; 9 – igipimo cy'imbaraga z'umurabyo w'impanuka; 10 – igipimo cy'imbaraga z'umurabyo ugaragara; 11 – lensi ireba; 12 – indorerwamo; 13 – icyitegererezo; 14 – transducer ya piezoelectric ya interineti; 15 – converter ya 2D; 16 – microcontroller ishyira ahantu; 17 – icyuma gihuza; 18 – sisitemu yo kubona ibikoresho by'ikoranabuhanga ifite imiyoboro myinshi ifite ibipimo bitandukanye byo gupima; 19 – mudasobwa bwite.
Ubuvuzi bwa Ultrasonic bukorwa ku buryo bukurikira. Laser ikora mu buryo bwo gukora ku giti cyayo; bityo igihe cyo gukora kwa laser ni \(\tau _L \sim 150~\upmu \text {s}\), kigizwe n'igihe kinini cya \(1.5~\upmu \text {s} \) buri kimwe. Imiterere y'igihe cya laser pulse n'umuvuduko wayo bigizwe n'ibahasha ifite frequency nke n'ihindagurika ry'inshuro nyinshi, hamwe n'inshuro mpuzandengo ya \(0.7~\text {MHz}\), nk'uko bigaragara ku Ishusho ya 2.- Ibahasha ifite frequency itanga ubushyuhe n'ihindagurika ry'ibikoresho nyuma yo gushonga no guhumeka, mu gihe igice gifite frequency nyinshi gitanga vibration ya Ultrasonic bitewe n'ingaruka za photoacoustic. Imiterere y'ihaha rya Ultrasonic rikorwa na laser igenwa ahanini n'imiterere y'igihe cy'ingufu za laser. Ni kuva kuri \(7~\text {kHz}\) kugeza kuri \(2~\text {MHz}\), kandi frequency yo hagati ni \(~ 0.7~\text {MHz}\). Amajwi aturuka ku ngaruka za photoacoustic yafashwe hakoreshejwe transducers za piezoelectric za broadband zikozwe muri filime za polyvinylidene fluoride. Ishusho ya waveform yafashwe n'uburyo bwayo bigaragazwa ku Ishusho ya 2. Bikwiye kumenyekana ko imiterere ya laser pulses isanzwe ya laser ikora mu buryo bwigenga.
Ikwirakwizwa ry'igihe gito ry'ubukana bw'amajwi ya laser (a) n'umuvuduko w'amajwi inyuma y'icyitegererezo (b), spectra ya laser pulse (c) n'amajwi ya ultrasonic pulse (d) byagaragaje impuzandengo y'amajwi arenga 300 ya laser pulse (umutuku) kuri laser pulse imwe (umutuku w'ubururu).
Dushobora gutandukanya neza ibice bifite umurongo mugari n'ibifite umurongo munini by'ubuvuzi bw'amajwi bihuye n'ishingiro ry'amajwi rito ry'amajwi rya laser pulse n'ihindagurika ry'amajwi rito, uko bikurikirana. Uburebure bw'imiraba y'amajwi ya laser pulse buterwa n'ishingiro ry'amajwi rito burenze \(40~\text {cm}\); bityo rero, ingaruka nyamukuru z'ibice bifite umurongo mugari w'amajwi bya acoustic ku miterere mito y'amajwi zitezwe.
Imikorere ya fiziki muri SLM iragoye kandi ibera icyarimwe ku bipimo bitandukanye by’ahantu n’ibihe. Kubwibyo, uburyo bwo gukoresha ingano nyinshi ni bwo bwiza cyane mu gusesengura inyigisho za SLM. Imiterere y’imibare igomba kubanza kuba iy’ibintu byinshi. Imiterere na thermofiziki by’uburyo bwinshi bwo gushonga kw’amazi bukorana n’ikirere cy’umwuka udakora neza bishobora gusobanurwa neza. Ibiranga ubushyuhe bw’ibintu muri SLM ni ibi bikurikira.
Igipimo cyo gushyushya no gukonjesha kigera kuri \(10^6~\text {K}/\text {s}\) /\text{ bitewe n'imirasire ya laser iri ahantu hamwe n'ubucucike bw'ingufu kugeza kuri \(10^{13}~\text {W} cm}^2\).
Uruhererekane rw'ihindagurika ry'ingufu rumara hagati ya 1 na \(10~\text {ms}\), ibyo bikaba bigira uruhare mu gukomera kw'agace gashonga mu gihe cyo gukonjesha.
Gushyushya vuba ubuso bw'icyitegererezo bituma habaho stress nyinshi za thermoelastic mu gice cy'ubuso. Igice gihagije (kugeza kuri 20%) cy'igice cy'ifu gihinduka umwuka cyane63, bigatuma habaho umuvuduko w'inyongera ku buso bitewe no kwimura laser. Kubera iyo mpamvu, stress iterwa nayo ihindura cyane imiterere y'igice, cyane cyane hafi y'inkunga n'ibintu bito by'imiterere. Umuvuduko mwinshi wo gushyushya mu gutera pulsed laser annealing utuma habaho imiraba ya ultrasonic strain ikwirakwira kuva ku buso ijya ku gice cy'ubuso. Kugira ngo haboneke amakuru nyayo ku mibare ku bijyanye n'stress yo mu gace n'ikwirakwizwa ry'stress, hakorwa isuzuma rya mesoscopic ry'ikibazo cyo guhinduka kwa elastic cyahujwe n'ubushyuhe n'ubwikorezi bw'ibice.
Ibigereranyo by’icyitegererezo birimo (1) ibigereranyo by’ubushyuhe bidahamye aho ubwikorezi bw’ubushyuhe bushingira ku miterere y’icyiciro (ifu, gushonga, polycrystalline) n’ubushyuhe, (2) ihindagurika ry’ihindagurika rya elastic nyuma yo gukurwaho kw’amashanyarazi n’ikigereranyo cyo kwaguka kwa thermoelastic. Ikibazo cy’agaciro k’umupaka kigenwa n’imiterere y’igerageza. Ihindagurika rya laser rihinduka risobanurwa ku buso bw’icyitegererezo. Gukonjesha kwa convective birimo guhinduranya ubushyuhe n’ihindagurika ry’umwuka. Ihindagurika ry’uburemere risobanurwa hashingiwe ku kubara igitutu cy’umwuka wuzuye w’ibikoresho bivamo umwuka. Isano ya elastoplastic stress-strain ikoreshwa aho stress ya thermoelastic ijyanye n’itandukaniro ry’ubushyuhe. Ku ngufu za nominelle \(300~\text {W}\), frequency \(10^5~\text {Hz}\), intermittent coefficient 100 na \(200~\upmu \text {m}\ ) by’umurambararo w’umurambararo ufatika.
Ishusho ya 3 igaragaza ibyavuye mu gupima imibare y'agace kashongeshejwe hakoreshejwe icyitegererezo cya macroscopic mathematical. Umurambararo w'agace ka fusion ni \(200~\upmu \text {m}\) (\(100~\upmu \text {m}\) radius) na \(40~\upmu \text {m}\) uburebure. Ibisubizo bya simulation bigaragaza ko ubushyuhe bw'ubuso buhinduka mu gace runaka uko igihe kigenda gihita nk'igihe cya \(100~\text {K}\) bitewe n'ihinduka ry'ingufu nyinshi mu mihindagurikire y'amajwi. Igipimo cyo gushyushya \(V_h\) no gukonjesha \(V_c\) kiri ku murongo wa \(10^7\) na \(10^6~\text {K}/\text {s}\), uko bikurikirana. Izi gaciro zirahuye neza n'isesengura ryacu ryabanje64. Itandukaniro ry'ubunini hagati ya \(V_h\) na \(V_c\) rituma habaho gushyuha cyane kw'urwego rw'ubuso, aho ubushyuhe bugera kuri substrate budahagije kugira ngo ubushyuhe bukureho. Kubwibyo, kuri \(t=26~\upmu \text {s}\) ubushyuhe bw'ubuso bugera ku \(4800~\text {K}\). Guhumeka cyane kw'ibikoresho bishobora gutuma ubuso bw'icyitegererezo bushyirwamo igitutu kirenze urugero kandi kikavaho.
Ibisubizo byo gupima imibare by'agace gashonga k'ingufu za laser imwe ku isahani y'icyitegererezo ya 316L. Igihe kuva ku ntangiriro y'ingufu kugeza ku burebure bw'ikidendezi cyashongeshejwe kigera ku gaciro ntarengwa ni \(180~\upmu\text {s}\). Isotherm\(T = T_L = 1723~\text {K}\) igaragaza umupaka uri hagati y'ibice by'amazi n'ibice bikomeye. Isobar (imirongo y'umuhondo) ihuye n'umuvuduko w'umusaruro ubarwa nk'uko ubushyuhe buri mu gice gikurikira. Kubwibyo, mu gice kiri hagati y'ibice bibiri bya isoline (isotherms\(T=T_L\) na isobar\(\sigma =\sigma _V(T)\)), igice gikomeye gikorerwa imitwaro ikomeye ya mekanike, bishobora gutuma habaho impinduka mu miterere ya mikoro.
Iyi ngaruka isobanurwa cyane mu Ishusho ya 4a, aho urwego rw'umuvuduko mu gace kashongeshejwe rugaragazwa nk'igihe n'intera uvuye ku buso. Ubwa mbere, imyitwarire y'umuvuduko ifitanye isano no guhindura imbaraga z'umuvuduko wa laser bivugwa mu Ishusho ya 2 haruguru. Umuvuduko ntarengwa \text{s}\) wa hafi \(10~\text {MPa}\) wagaragaye ahagana \(t=26~\upmu). Icya kabiri, ihindagurika ry'umuvuduko wo mu gace aho ugenzurirwa rifite imiterere imwe n'iy'ihindagurika rya \(500~\text {kHz}\). Ibi bivuze ko imiraba y'umuvuduko wa ultrasonic ikorerwa ku buso hanyuma igakwirakwira mu gice cy'ubutaka.
Ibiranga imiterere y’agace k’ihindagurika ry’ikirere hafi y’agace k’ihindagurika ry’ikirere bigaragara ku ishusho ya 4b. Gukuraho imirasire ya laser n’ihindagurika ry’ikirere bitanga imiraba ya elastic deformation ikwirakwira mu gice cy’izuba. Nkuko bigaragara ku ishusho, hari ibyiciro bibiri byo gukora imihangayiko. Mu cyiciro cya mbere cya \(t < 40~\upmu \text {s}\), imihangayiko ya Mises izamuka ikagera kuri \(8~\text {MPa}\) hamwe n’ihindagurika ry’ikirere risa n’iry’ubuso. Iyi mihangayiko ibaho bitewe no gukuramo imirasire ya laser, kandi nta mihangayiko ya thermoelastic yagaragaye mu bice by’igenzura kuko agace k’izuba kabanje kubamo ubushyuhe kari gato cyane. Iyo ubushyuhe bumenetse mu gice cy’izuba, aho kugenzura bitanga imihangayiko myinshi ya thermoelastic hejuru ya \(40~\text {MPa}\).
Ibipimo bya stress byahinduwe bigira ingaruka zikomeye ku buryo stress-liquid interface igaragara kandi ishobora kuba ari bwo buryo bwo kugenzura inzira yo gukonja. Ingano y'agace k'ihindagurika ry'ikirere ni inshuro 2 kugeza kuri 3 ugereranyije n'agace k'ihindagurika ry'ikirere. Nkuko bigaragara ku Ishusho ya 3, aho isotherm ishonga iherereye n'urwego rw'stress rungana n'umusaruro biragereranywa. Ibi bivuze ko imirasire ya laser itera imbaraga nyinshi mu bice by'ahantu hamwe n'umurambararo mwiza uri hagati ya 300 na \(800~\upmu \text {m}\) bitewe n'igihe cy'ako kanya.
Bityo rero, uburyo bugoye bwo guhindura imiterere y’icyuma gitera imbaraga cya laser butuma habaho ingaruka za ultrasound. Uburyo bwo guhitamo imiterere mito buratandukanye ugereranije na SLM nta gukurura ultrasonic. Uduce duto tudakomeye dutuma habaho imikorere yo gukanda no kwaguka mu gice gikomeye. Bityo, gushyiraho imipaka mishya y’ibinyampeke n’imipaka y’ibinyampeke biba bishoboka. Bityo, imiterere y’imiterere mito ishobora guhinduka nkana, nk'uko bigaragara hepfo. Imyanzuro yabonetse itanga uburyo bwo gukora prototype ya SLM ikoreshwa na ultrasound. Muri iki gihe, inductor 26 ya piezoelectric ikoreshwa ahandi ishobora gukurwaho.
(a) Umuvuduko nk'uko igihe gihagaze, ubarwa ku ntera zitandukanye uvuye ku buso bwa 0, 20 na \(40~\upmu \text {m}\) ukurikije umurongo w'ubusumbane. (b) Umuvuduko ushingiye ku gihe wa Von Mises ubarwa muri matrix ikomeye ku ntera ya 70, 120 na \(170~\upmu \text {m}\) uvuye ku buso bw'icyitegererezo.
Igerageza ryakozwe ku byapa bya AISI 321H by'icyuma kitagira umugese bifite ingano \(20\inshuro 20\inshuro 5~\inyandiko {mm}\). Nyuma ya buri kuguruka kwa laser, isahani iragenda \(50~\upmu \inyandiko {m}\), kandi urukenyerero rwa laser ku buso bw'intego rungana na \(100~\upmu \inyandiko {m}\). Hakurikiraho inzira eshanu z'urutare zinyuramo mu nzira imwe kugira ngo hakorwe ishonga ry'ibikoresho byatunganyijwe kugira ngo binoze. Mu bihe byose, agace kavuyemo ishonga kari karakozwe mu buryo bwa sonicated, bitewe n'igice cy'imirasire ya laser. Ibi bituma ubuso bw'ingano bugabanuka inshuro zirenga 5. Ishusho ya 5 igaragaza uburyo imiterere y'agace kavuyemo ishonga ya laser ihinduka hamwe n'umubare w'ingendo zo kuvamo ishonga nyuma.
Udupande duto (a, d, g, j) na (b, e, h, k) – imiterere mito y’uturere twashongeshejwe na laser, udupande duto (c, f, i, l) – imiterere y’udupande tw’amabara. Igicucu kigaragaza uduce dukoreshwa mu kubara histogram. Amabara ajyanye n’uturere tw’udupande (reba agace k’amabara hejuru ya histogram. Udupande duto (ac) duhuye n’icyuma kidatunganyijwe, naho udupande duto (df), (gi), (jl) duhuye n’udupande 1, 3 na 5.
Kubera ko ingufu za laser pulse zidahinduka hagati y’inzira zikurikira, ubujyakuzimu bw’agace kashongeshejwe ni bumwe. Bityo, umuyoboro ukurikiraho "utwikira" burundu uwabanje. Ariko, histogram igaragaza ko ubuso bw’ingano y’impuzandengo n’ubugari bugabanuka uko umubare w’inzira wiyongera. Ibi bishobora kwerekana ko laser irimo gukora ku gice cy’ubutaka aho kuba ku gishonga.
Gutunganya ibinyampeke bishobora guterwa no gukonja vuba kw'ikidendezi cyashongeshejwe65. Hari ubundi bushakashatsi bwakozwe aho ubuso bw'ibyuma bitarangirika (321H na 316L) bwahuye n'imirasire ya laser ikomeza kugaragara mu kirere (Ishusho ya 6) n'ingufu (Ishusho ya 7). Ingufu za laser zisanzwe (300 W na 100 W, uko bikurikirana) n'ubujyakuzimu bw'ikidendezi cyashongeshejwe biri hafi y'ibyavuye mu bushakashatsi bwa laser ya Nd:YAG mu buryo bwo gukora bufunguye. Ariko, imiterere isanzwe ya columnar yagaragaye.
Imiterere mito y'agace kashongeshejwe na laser ka laser ikomeza gushonga (ingufu zihoraho za 300 W, umuvuduko wa 200 mm/s wo gupima, icyuma kitagira umugese cya AISI 321H).
(a) Imiterere mito na (b) amashusho ya electron backscatter diffraction y'agace kashongeshejwe na laser mu cyuma gishyuha hamwe na laser ikomeza kuzura (ingufu zihoraho za 100 W, umuvuduko wa 200 mm/s, icyuma kitagira umugese cya AISI 316L)\ (\sim 2~\text {mbar}\).
Bityo rero, bigaragara neza ko uburyo bugoye bwo guhindura imbaraga za laser pulse bugira ingaruka zikomeye ku miterere mito ikomokaho. Twizera ko iyi ngaruka ari iy'ikoranabuhanga kandi ibaho bitewe no gukora imitingito ya ultrasound ikwirakwira iva ku buso bwarashweho n'imirasire y'isukari igera mu rugero rwinshi. Ibisubizo nk'ibyo byabonetse muri 13, 26, 34, 66, 67 hakoreshejwe transducers za piezoelectric zo hanze na sonotrodes zitanga ultrasound ikomeye mu bikoresho bitandukanye birimo Ti-6Al-4V alloy 26 n'icyuma kitagira umugese 34. Uburyo bushoboka buratekerezwaho gutya. Ultrasound ikomeye ishobora gutera cavitation acoustic, nk'uko bigaragazwa muri ultrafast in situ synchrotron X-ray imaging. Gusenyuka kw'utubumbe twa cavitation bituma habaho imitingito ya shock mu bikoresho bishongeshejwe, aho umuvuduko w'imbere ugera kuri \(100~\text {MPa}\)69. Iyo mitingito ya shock ishobora kuba ikomeye bihagije kugira ngo itere imbere ikorwa rya nucleus ikomeye mu bintu byinshi, bigahungabanya imiterere isanzwe y'ingano ya columnar ya gukora inyongeramusaruro ku rundi rwego.
Aha, turatanga ubundi buryo butuma ibintu bihinduka binyuze mu gushonga cyane. Nyuma yo gushonga, ibintu biba biri ku bushyuhe bwinshi hafi y’aho bishongesha kandi bifite umuvuduko muto cyane w’umusaruro. Imiraba ikomeye ya ultrasonic ishobora gutuma pulasitiki itemba igahindura imiterere y’ibinyampeke by’ibintu bishyushye, byakomejwe gusa. Ariko, amakuru yizewe ku igerageza ku bushyuhe buterwa n’umuvuduko w’umusaruro araboneka kuri \(T\lesssim 1150~\text {K}\) (reba Ishusho ya 8). Kubwibyo, kugira ngo tugerageze iki gitekerezo, twakoze simulation za molekile (MD) z’ibinyabutabire bya Fe-Cr-Ni bisa na AISI 316 L steel kugira ngo dusuzume imyitwarire y’umuvuduko w’umusaruro hafi y’aho bishongesha. Kugira ngo tubare umuvuduko w’umusaruro, twakoresheje tekiniki ya MD shear stress relaxation irambuye muri 70, 71, 72, 73. Ku bijyanye no kubara interatomike, twakoresheje Embedded Atomic Model (EAM) yo muri 74. Simulation za MD zakozwe hakoreshejwe LAMMPS codes 75,76. Ibisobanuro birambuye kuri simulation za MD bizatangazwa ahandi. Ibisubizo byo kubara MD by’umusaruro Imihangayiko nk'uko ubushyuhe buhagaze igaragazwa ku Ishusho ya 8 hamwe n'amakuru aboneka ku igerageza n'andi masuzuma77,78,79,80,81,82.
Umuvuduko w'umusaruro ku cyuma cya AISI cyo mu rwego rwa 316 cya austenitic stainless steel n'imiterere yacyo ugereranyije n'ubushyuhe ku bikoresho bya MD. Ibipimo by'igerageza bivuye ku byavuzwe: (a) 77, (b) 78, (c) 79, (d) 80, (e) 81. reba. (f) 82 ni icyitegererezo cy'ubushyuhe n'umusaruro bishingira ku gupima umuvuduko mu murongo mu gihe cyo gukora inyongera zifashijwe na laser. Ibisubizo by'ibyitegererezo binini bya MD muri ubu bushakashatsi byagaragajwe nka \(\vartriangleleft\) ku cyuma kimwe kitagira inenge kitagira inenge na \(\vartriangleright\) ku binyampeke bitagira iherezo hashingiwe ku bunini bw'ibinyampeke binyuze mu mibanire ya Hall-Petch\(d = 50~\upmu \text {m}\).
Bigaragara ko kuri \(T>1500~\text {K}\) umuvuduko w'umusaruro ugabanuka munsi ya \(40~\text {MPa}\). Ku rundi ruhande, ibigereranyo bigaragaza ko amplitude ya ultrasonic ikorwa na laser irenga \(40~\text {MPa}\) (reba Ishusho ya 4b), ibi bikaba bihagije kugira ngo pulasitiki itembera mu bikoresho bishyushye bikimara gukomera.
Imiterere y’icyuma kitagira umugese cya 12Cr18Ni10Ti (AISI 321H) cya austenitic stainless steel muri SLM yasuzumwe mu buryo bw’igerageza hakoreshejwe isoko rya laser rikoresha imbaraga nyinshi.
Igabanuka ry'ingano y'ibinyampeke mu gace gashongesha laser ryagaragaye bitewe no gushongesha laser bidahwema nyuma y'inshuro 1, 3 cyangwa 5.
Imiterere ya macroscopic igaragaza ko ingano y'agace aho imiterere ya ultrasound ishobora kugira ingaruka nziza ku gice cyo hejuru cy'urukiramende igera kuri \(1~\text {mm}\).
Icyitegererezo cya MD cya mikorosikopi kigaragaza ko imbaraga z'umusaruro wa AISI 316 austenitic stainless steel zagabanutse cyane zikagera kuri \(40~\text {MPa}\) hafi y'aho ishongeshereza.
Ibisubizo byabonetse bigaragaza uburyo bwo kugenzura imiterere y’ibikoresho hakoreshejwe uburyo buhambaye bwo gutunganya laser kandi bushobora kuba ishingiro ryo gukora impinduka nshya za tekiniki ya SLM ikoresha pulse.
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