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An gabatar da sabuwar hanya bisa ga narkewar laser mai zaɓi don sarrafa ƙananan tsarin samfura a cikin tsarin masana'antu. Tsarin ya dogara ne akan samar da raƙuman ultrasonic masu ƙarfi a cikin tafkin narke ta hanyar hasken laser mai rikitarwa mai rikitarwa. Nazarin gwaji da kwaikwayon lambobi sun nuna cewa wannan hanyar sarrafawa tana da yuwuwar a fasaha kuma ana iya haɗa ta yadda ya kamata cikin ƙirar injunan narke laser na zamani.
Ƙirƙirar ƙari (AM) na sassa masu siffa mai rikitarwa ya bunƙasa sosai a cikin 'yan shekarun nan. Duk da haka, duk da nau'ikan hanyoyin ƙera ƙari, gami da narkewar laser mai zaɓi (SLM)1,2,3, adana ƙarfe kai tsaye na laser4,5,6, narkewar katakon lantarki7,8 da sauransu9,10, sassan na iya zama marasa lahani. Wannan galibi saboda takamaiman halayen tsarin ƙarfafa tafkin da aka narke wanda ke da alaƙa da manyan matakan zafi, yawan sanyaya mai yawa, da kuma sarkakiyar zagayowar dumama a cikin narkewa da sake narkewa kayan11, wanda ke haifar da haɓakar hatsi na epitaxial da babban porosity12,13. Sakamakon ya nuna cewa , yana da mahimmanci a sarrafa matakan zafi, ƙimar sanyaya, da abun da ke cikin ƙarfe, ko a yi amfani da ƙarin girgiza ta jiki ta hanyar filayen waje na kaddarorin daban-daban (misali, duban dan tayi) don cimma kyawawan tsarin hatsi masu daidaito.
Littattafai da yawa suna da alaƙa da tasirin maganin girgiza akan tsarin ƙarfafawa a cikin hanyoyin siminti na al'ada14,15. Duk da haka, amfani da filin waje a kan narkewar babban abu ba ya samar da ƙaramin tsari na kayan da ake so. Idan girman matakin ruwa ya yi ƙanƙanta, yanayin yana canzawa sosai. A wannan yanayin, filin waje yana shafar tsarin ƙarfafawa sosai. An yi la'akari da tasirin lantarki a lokacin filayen sauti masu ƙarfi16,17,18,19,20,21,22,23,24,25,26,27, stirring arc28 da oscillation29, pulsed plasma arcs30,31 da sauran hanyoyi32. Haɗa zuwa substrate ta amfani da tushen ultrasonic mai ƙarfi na waje (a 20 kHz). Ana danganta gyaran hatsi da ultrasound ke haifarwa da ƙara yawan yankin sanyaya kayan saboda raguwar yanayin zafi da haɓaka ultrasonic don samar da sabbin kristali ta hanyar cavitation.
A cikin wannan aikin, mun bincika yiwuwar canza tsarin hatsi na ƙarfen bakin ƙarfe na austenitic ta hanyar yin amfani da wurin narkewa tare da raƙuman sauti da laser mai narkewa ya samar. Tsarin ƙarfin da ya faru na hasken laser akan matsakaici mai ɗaukar haske yana haifar da samar da raƙuman ultrasonic, waɗanda ke canza tsarin kayan. Wannan canjin ƙarfin hasken laser za a iya haɗa shi cikin firintocin SLM 3D na yanzu cikin sauƙi. An yi gwaje-gwajen a cikin wannan aikin akan faranti na bakin ƙarfe waɗanda samansu ya fallasa ga hasken laser mai ƙarfi. Don haka, a zahiri, ana yin maganin saman laser. Koyaya, idan an yi irin wannan maganin laser akan saman kowane Layer, yayin gina Layer-by-layer, ana cimma tasirin akan dukkan girman ko akan wasu sassan ƙarar. A takaice dai, idan an gina ɓangaren Layer-by-layer, maganin saman laser na kowane Layer yayi daidai da "maganin girman laser".
Yayin da a cikin maganin ultrasonic na ƙaho na ultrasonic, makamashin ultrasonic na raƙuman sauti na tsaye yana rarraba a ko'ina cikin ɓangaren, yayin da ƙarfin ultrasonic da laser ke haifarwa yana da ƙarfi sosai kusa da inda ake shaƙar hasken laser. Amfani da sonotrode a cikin injin haɗin gado na SLM yana da rikitarwa saboda saman saman gadon foda da aka fallasa ga hasken laser ya kamata ya kasance a tsaye. Bugu da ƙari, babu damuwa na injiniya a saman saman ɓangaren. Saboda haka, damuwar sauti tana kusa da sifili kuma saurin barbashi yana da matsakaicin girma akan dukkan saman saman ɓangaren. Matsin sauti a cikin dukkan tafkin da aka narke ba zai iya wuce 0.1% na matsakaicin matsin lamba da kan walda ya samar ba, saboda tsawon raƙuman ultrasonic tare da mita na 20 kHz a cikin bakin karfe shine \(\sim 0.3~\text {m}\), kuma Zurfin yawanci ƙasa da \(\sim 0.3~\text {mm}\).Saboda haka, tasirin duban dan tayi akan cavitation na iya zama ƙarami.
Ya kamata a lura cewa amfani da hasken laser mai ƙarfi a cikin ajiyar ƙarfe na laser kai tsaye wani yanki ne mai aiki na bincike35,36,37,38.
Tasirin zafi na abin da ya faru na hasken laser a kan matsakaici shine tushen kusan dukkanin dabarun laser 39, 40 don sarrafa kayan aiki, kamar yankewa41, walda, taurarewa, haƙa rami42, tsaftace saman, haɗa saman, goge saman43, da sauransu. Ƙirƙirar laser ɗin ta ƙarfafa sabbin ci gaba a cikin dabarun sarrafa kayan aiki, kuma an taƙaita sakamakon farko a cikin bita da takardu da yawa44,45,46.
Ya kamata a lura cewa duk wani aiki mara tsayawa akan matsakaici, gami da aikin lasing akan matsakaiciyar sha, yana haifar da haɓakar raƙuman sauti a cikinsa tare da inganci ko ƙarancin inganci. Da farko, babban abin da aka fi mayar da hankali a kai shine haɓakar laser na raƙuman ruwa a cikin ruwa da hanyoyin motsa zafi daban-daban na sauti (faɗaɗa zafi, ƙafewa, canjin girma yayin canjin lokaci, matsewa, da sauransu) 47, 48, 49. Labarai da yawa50, 51, 52 suna ba da nazarin ka'idoji na wannan tsari da yuwuwar aikace-aikacensa na aiki.
Daga baya an tattauna waɗannan batutuwa a taruka daban-daban, kuma motsin laser na duban dan tayi yana da amfani a aikace-aikacen masana'antu na fasahar laser53 da magani54. Saboda haka, ana iya la'akari da cewa an kafa ainihin ra'ayin tsarin da hasken laser mai bugawa ke aiki akan hanyar sha. Ana amfani da duban laser na duban dan tayi don gano lahani na samfuran da SLM ta ƙera55,56.
Tasirin raƙuman girgiza da laser ke haifarwa akan kayan aiki shine tushen bugun laser peening57,58,59, wanda kuma ana amfani dashi don maganin saman sassan da aka ƙera da ƙari60. Duk da haka, ƙarfafa bugun laser ya fi tasiri akan bugun laser nanosecond da saman da aka ɗora da injina (misali, tare da Layer na ruwa)59 saboda nauyin injina yana ƙara matsin lamba mafi girma.
An gudanar da gwaje-gwaje don bincika yiwuwar tasirin filayen jiki daban-daban akan ƙaramin tsarin kayan da aka taurara. An nuna zane-zanen aiki na saitin gwaji a Hoto na 1. An yi amfani da laser mai ƙarfi na Nd:YAG wanda ke aiki a cikin yanayin gudu kyauta (lokacin bugun jini \(\tau _L \sim 150~\upmu \text {s}\ )). Kowace bugun laser ana wucewa ta cikin jerin matatun mai yawa tsaka-tsaki da tsarin farantin raba katako. Dangane da haɗin matatun mai yawa tsaka-tsaki, ƙarfin bugun da ke kan manufa ya bambanta daga \(E_L \sim 20~\text {mJ}\) zuwa \(E_L \sim 100~\text {mJ}\) .Hasken laser da aka nuna daga mai raba katako ana ciyar da shi zuwa photodiode don samun bayanai a lokaci guda, kuma ana amfani da calorimeters guda biyu (photodiodes tare da dogon lokacin amsawa wanda ya wuce \(1~\text {ms}\)) don tantance abin da ya faru zuwa kuma ya nuna daga abin da aka nufa, da kuma mita biyu na wutar lantarki (photodiodes tare da gajeren amsa sau\(<10~\text {ns}\)) don tantance abin da ya faru da ƙarfin gani da aka nuna. An daidaita ma'aunin kuzari da ma'aunin wutar lantarki don ba da ƙima a cikin raka'a masu cikakken ƙarfi ta amfani da na'urar gano zafi ta Gentec-EO XLP12-3S-H2-D0 da madubin dielectric da aka ɗora a wurin samfurin. Mayar da hasken wutar lantarki zuwa ga abin da aka nufa ta amfani da ruwan tabarau (rufin hana haske a \(1.06 \upmu \text {m}\), tsawon mai da hankali \(160~\text {mm}\)) da kugu a saman abin da aka nufa 60– \(100~\upmu\text {m}\).
Tsarin aiki na tsarin gwaji: 1—laser; 2—beam ɗin laser; 3—matatar yawan tsaka-tsaki; 4—photodiode mai aiki tare; 5—mai raba beam; 6—diaphragm; 7—calorimeter na beam ɗin da ya faru; 8 – calorimeter na beam ɗin da aka nuna; 9 – mitar wutar lantarki ta beam ɗin da ya faru; 10 – mitar wutar lantarki ta beam ɗin da aka nuna; 11 – ruwan tabarau mai mai da hankali; 12 – madubi; 13 – samfuri; 14 – na'urar transducer ta piezoelectric mai sauri; 15 – mai canza 2D; 16 – na'urar sarrafa microcontroller mai matsayi; 17 – na'urar daidaitawa; 18 – tsarin siyan dijital mai tashoshi da yawa tare da ƙimar samfura daban-daban; 19 – kwamfuta ta mutum.
Ana gudanar da maganin ultrasonic kamar haka. Laser ɗin yana aiki a yanayin gudu kyauta; saboda haka tsawon lokacin bugun laser shine \(\tau _L \sim 150~\upmu \text {s}\), wanda ya ƙunshi tsawon lokaci da yawa na kusan \(1.5~\upmu \text {s} \) kowanne. Siffar lokaci ta bugun laser da bakan ta sun ƙunshi ambulan mai ƙarancin mita da kuma daidaitaccen mita mai yawa, tare da matsakaicin mita na kusan \(0.7~\text {MHz}\), kamar yadda aka nuna a Hoto na 2.- Ambulan mita yana ba da dumama da narkewa da ƙafewar kayan daga baya, yayin da babban sashi na mita yana ba da girgizar ultrasonic saboda tasirin photoacoustic. Tsarin raƙuman ultrasonic da laser ke samarwa galibi ana ƙaddara shi ne ta hanyar siffar lokacin ƙarfin bugun laser. Yana daga \(7~\text {kHz}\) zuwa \ (2~\text {MHz}\), kuma mitar tsakiya ita ce \(~ 0.7~\text {MHz}\). An yi rikodin bugun sauti saboda tasirin photoacoustic ta amfani da na'urorin transducers na piezoelectric broadband da aka yi da fina-finan polyvinylidene fluoride. An nuna siffar raƙuman ruwa da aka yi rikodi da kuma bakan sa a Hoto na 2. Ya kamata a lura cewa siffar bugun laser ta kasance ta hanyar laser mai aiki da kansa.
Rarrabawar lokaci na ƙarfin bugun laser (a) da saurin sauti a saman bayan samfurin (b), spectra na bugun laser (c) da kuma ultrasonic pulse (d) sun kai matsakaicin bugun laser sama da 300 (layin ja) ga bugun laser guda ɗaya (layin shuɗi).
Za mu iya bambance ƙananan mitoci da manyan sassan maganin sauti waɗanda suka yi daidai da ƙaramin mitoci na bugun laser da kuma babban mitoci, bi da bi. Tsawon raƙuman raƙuman sauti da aka samar ta hanyar murfin laser ya wuce \(40~\text {cm}\); saboda haka, ana sa ran babban tasirin sassan babban mitoci na siginar sauti akan ƙananan tsarin.
Tsarin jiki a cikin SLM yana da rikitarwa kuma yana faruwa a lokaci guda akan ma'auni daban-daban na sarari da na lokaci. Saboda haka, hanyoyin sikelin da yawa sun fi dacewa don nazarin ka'idar SLM. Samfuran lissafi yakamata su zama na jiki da yawa. Za a iya bayyana injiniyoyi da thermophysics na matsakaici mai yawa "narkewar ruwa mai ƙarfi" wanda ke hulɗa da yanayin iskar gas mara aiki yadda ya kamata. Halayen nauyin zafi na kayan abu a cikin SLM sune kamar haka.
Yawan dumama da sanyaya har zuwa \(10^6~\text {K}/\text {s}\) /\text{ saboda hasken laser na gida tare da ƙarfin da ke da yawa har zuwa \(10^{13}~\text {W} cm}^2\).
Zagayen narkewar-ƙarfafawa yana ɗaukar tsakanin 1 da „(10~\text {ms}\), wanda ke ba da gudummawa ga saurin ƙarfafa yankin narkewa yayin sanyaya.
Dumama saman samfurin cikin sauri yana haifar da samuwar matsin lamba mai yawa a cikin saman saman. Isasshen (har zuwa 20%) na saman foda yana ƙafe sosai63, wanda ke haifar da ƙarin nauyin matsi akan saman don mayar da martani ga cirewar laser. Sakamakon haka, matsalar da aka haifar tana ɓata yanayin ɓangaren sosai, musamman kusa da tallafi da siraran abubuwan tsarin. Babban ƙimar dumama a cikin bugun laser mai pulsed yana haifar da samar da raƙuman matsin lamba na ultrasonic waɗanda ke yaduwa daga saman zuwa substrate. Domin samun bayanai masu inganci kan rarraba damuwa da damuwa na gida, ana yin kwaikwayon mesoscopic na matsalar nakasar roba da aka haɗa zuwa zafi da canja wurin taro.
Lissafin da ke kula da samfurin sun haɗa da (1) daidaitattun daidaiton canja wurin zafi mara tsayayye inda yanayin aiki na zafi ya dogara da yanayin lokaci (foda, narkewa, polycrystalline) da zafin jiki, (2) canzawa a cikin nakasar roba bayan cirewa da kuma daidaita fadada thermoelastic. Matsalar ƙimar iyaka ana ƙayyade ta ta hanyar yanayin gwaji. An ayyana kwararar laser mai daidaitawa akan saman samfurin. Sanyayawar convective ta haɗa da musayar zafi mai gudana da kwararar ƙafewa. An ayyana kwararar taro bisa ga lissafin matsin lamba mai cike da tururi na kayan ƙafewa. Ana amfani da alaƙar damuwa da damuwa ta elastoplastic inda damuwar thermoelastic ta yi daidai da bambancin zafin jiki. Don ƙarfin sunadaran \(300~\text {W}\), mita \(10^5~\text {Hz}\), ma'aunin lokaci-lokaci 100 da \(200~\upmu \text {m}\ ) na diamita mai tasiri na katako.
Siffa ta 3 tana nuna sakamakon kwaikwayon lambobi na yankin narkakken mai ta amfani da samfurin lissafi mai kama da macroscopic. Diamita na yankin haɗakarwa shine zurfin \(200~\upmu \text {m}\) (\(100~\upmu \text {m}\) radius) da \(40~\upmu \text {m}\). Sakamakon kwaikwayon ya nuna cewa zafin saman ya bambanta a gida tare da lokaci kamar \(100~\text {K}\) saboda babban abin da ke faruwa na canjin bugun jini. Yawan dumama \(V_h\) da sanyaya \(V_c\) suna kan tsari na \(10^7\) da \(10^6~\text {K}/\text {s}\), bi da bi. Waɗannan ƙimar sun yi daidai da bincikenmu na baya64. Bambancin girma tsakanin \(V_h\) da \(V_c\) yana haifar da zafi mai sauri na saman, inda isar da zafi zuwa substrate bai isa ya cire zafi ba. Saboda haka, a \(t=26~\upmu \text {s}\) zafin saman yana kaiwa har zuwa \(4800~\text {K}\). Ƙarfin fitar da kayan na iya sa saman samfurin ya fuskanci matsin lamba mai yawa da kuma barewa.
Sakamakon kwaikwayo na lambobi na yankin narkewa na bugun bugun laser guda ɗaya akan farantin samfurin 316L. Lokacin daga farkon bugun jini zuwa zurfin tafkin narkewa wanda ya kai matsakaicin ƙimar shine \(180~\upmu\text {s}\).Isotherm\(T = T_L = 1723~\text {K}\) yana wakiltar iyaka tsakanin matakan ruwa da ƙarfi.Isobars (layukan rawaya) sun yi daidai da matsin lamba na amfanin ƙasa da aka ƙididdige azaman aikin zafin jiki a sashe na gaba. Saboda haka, a cikin yankin tsakanin isolines guda biyu (isotherms\(T=T_L\) da isobars\(\sigma =\sigma _V(T)\)), matakin ƙarfi yana fuskantar manyan nauyin injiniya, wanda zai iya haifar da canje-canje a cikin tsarin microstructure.
An ƙara bayyana wannan tasirin a cikin Hoto na 4a, inda aka zana matakin matsin lamba a yankin narkakken a matsayin aikin lokaci da nisa daga saman. Da farko, yanayin matsin lamba yana da alaƙa da daidaitawar ƙarfin bugun laser da aka bayyana a Hoto na 2 a sama. An lura da matsakaicin matsin lamba \text{s}\) na kusan \(10~\text {MPa}\) a kusan \(t=26~\upmu). Na biyu, canjin matsin lamba na gida a wurin sarrafawa yana da halaye iri ɗaya na juyawa kamar mitar \(500~\text {kHz}\). Wannan yana nufin cewa raƙuman matsin lamba na ultrasonic ana samar da su a saman sannan a yaɗu zuwa cikin substrate.
An nuna halayen da aka ƙididdige na yankin nakasawa kusa da yankin narkewa a cikin Hoto na 4b. Nakasawa ta Laser da damuwa ta thermoelastic suna haifar da raƙuman nakasawa masu laushi waɗanda ke yaduwa cikin substrate. Kamar yadda za a iya gani daga hoton, akwai matakai biyu na samar da damuwa. A lokacin mataki na farko na \(t < 40~\upmu \text {s}\), damuwar Mises ta tashi zuwa \(8~\text {MPa}\) tare da daidaitawa mai kama da matsin saman. Wannan damuwa tana faruwa ne saboda nakasawa ta laser, kuma ba a lura da damuwar thermoelastic a wuraren sarrafawa ba saboda yankin farko da zafi ya shafa ya yi ƙanƙanta. Lokacin da aka wargaza zafi a cikin substrate, wurin sarrafawa yana haifar da matsin lamba mai zafi sama da \(40~\text {MPa}\).
Matakan damuwa da aka daidaita da aka samu suna da tasiri mai mahimmanci akan haɗin gwiwa mai ƙarfi da ruwa kuma yana iya zama hanyar sarrafawa da ke jagorantar hanyar ƙarfafawa. Girman yankin nakasawa ya fi girma sau 2 zuwa 3 fiye da na yankin narkewa. Kamar yadda aka nuna a Hoto na 3, an kwatanta wurin isotherm na narkewa da matakin damuwa daidai da matsin lamba na samarwa. Wannan yana nufin cewa hasken laser mai pulsed yana samar da manyan nauyin injiniya a yankunan da ke da iyaka mai tasiri tsakanin 300 da 800 ~ 800 \ text {m} \) ya danganta da lokacin nan take.
Saboda haka, sarkakiyar daidaitawar laser mai bugun zuciya tana haifar da tasirin ultrasonic. Hanyar zaɓin tsarin microstructure ta bambanta idan aka kwatanta da SLM ba tare da ɗaukar nauyin ultrasonic ba. Yankunan da ba su da kwanciyar hankali suna haifar da zagayowar matsi da shimfiɗawa lokaci-lokaci a cikin matakin ƙarfi. Don haka, ƙirƙirar sabbin iyakokin hatsi da iyakokin ƙananan hatsi ya zama mai yiwuwa. Saboda haka, ana iya canza halayen microstructural da gangan, kamar yadda aka nuna a ƙasa. Sakamakon da aka samu yana ba da damar tsara samfurin SLM mai sarrafa bugun zuciya wanda aka haifar da tsarin pulse modulation. A wannan yanayin, ana iya cire inductor piezoelectric 26 da aka yi amfani da shi a wasu wurare.
(a) Matsi a matsayin aikin lokaci, wanda aka ƙididdige shi a nisan daban-daban daga saman 0, 20 da kuma „(40~\upmu \text {m}\) tare da ma'aunin daidaito.(b) Von Mises, wanda ya dogara da lokaci, yana ƙididdige damuwa a cikin matrix mai ƙarfi a nisan 70, 120 da „(170~\upmu \text {m}\) daga saman samfurin.
An yi gwaje-gwaje a kan faranti na bakin ƙarfe AISI 321H masu girma \(20\sau 20\sau 5~\text {mm}\). Bayan kowace bugun laser, farantin yana motsawa \(50~\upmu \text {m}\), kuma kugu na laser a saman abin da aka nufa yana kusan \(100~\upmu \text {m}\). Har zuwa rabe-raben katako guda biyar masu zuwa ana yin su tare da hanya ɗaya don haifar da sake narkewar kayan da aka sarrafa don tsaftace hatsi. A duk lokuta, an yi amfani da yankin da aka narke, ya danganta da ɓangaren juyawa na radiation na laser. Wannan yana haifar da raguwa fiye da ninki 5 a matsakaicin yankin hatsi. Hoto na 5 yana nuna yadda ƙaramin tsarin yankin da laser ya narke yake canzawa tare da adadin zagayowar sake narkewa na gaba (wucewa).
Ƙananan siffofi (a,d,g,j) da (b,e,h,k) – ƙananan siffofi na yankunan da aka narke ta hanyar laser, ƙananan siffofi (c,f,i,l) – rarrabawar yanki na hatsi masu launi. Inuwa tana wakiltar ƙwayoyin da ake amfani da su don ƙididdige histogram. Launuka suna daidai da yankunan hatsi (duba sandar launi a saman histogram. Ƙananan siffofi (ac) suna daidai da ƙarfe mara kyau wanda ba a yi masa magani ba, kuma ƙananan siffofi (df), (gi), (jl) sun dace da 1, 3 da 5 na narkewa.
Tunda ƙarfin bugun laser ba ya canzawa tsakanin wucewar da ke biyo baya, zurfin yankin narkewa iri ɗaya ne. Saboda haka, tashar da ke biyo baya ta “rufe” wanda ya gabata gaba ɗaya. Duk da haka, histogram ɗin ya nuna cewa matsakaicin yanki da matsakaicin yanki na hatsi yana raguwa tare da ƙaruwar adadin wucewar. Wannan na iya nuna cewa laser yana aiki akan substrate maimakon narkewar.
Gyaran hatsi na iya faruwa ne sakamakon sanyayawar wurin narkakken ruwa cikin sauri65. An gudanar da wani gwaji inda saman faranti na bakin karfe (321H da 316L) suka fuskanci ci gaba da hasken laser a cikin yanayi (Hoto na 6) da kuma injin tsabtace ruwa (Hoto na 7). Matsakaicin ƙarfin laser (300 W da 100 W, bi da bi) da zurfin wurin narkakken ruwa suna kusa da sakamakon gwaji na laser Nd:YAG a cikin yanayin gudu kyauta. Duk da haka, an lura da tsarin ginshiƙi na yau da kullun.
Tsarin ƙananan yanki na narkewar laser na laser mai ci gaba da raƙuman ruwa (ƙarfin wutar lantarki mai 300 W, saurin duba 200 mm/s, bakin ƙarfe AISI 321H).
(a) Tsarin ƙananan ƙwayoyin halitta da (b) hotunan watsawar electron baya-bayan lantarki na yankin da laser ya narke a cikin injin tsabtace ruwa tare da laser mai ci gaba da raƙuman ruwa (ƙarfin da ba ya canzawa 100 W, saurin duba 200 mm/s, AISI 316L bakin ƙarfe)\ (\sim 2~\text {mbar}\).
Saboda haka, an nuna a fili cewa rikitaccen tsarin ƙarfin bugun laser yana da tasiri mai mahimmanci akan tsarin da aka samu. Mun yi imanin cewa wannan tasirin yana da alaƙa da injiniya kuma yana faruwa ne saboda samar da girgizar ultrasonic da ke yaduwa daga saman da aka haskaka na narkewar cikin zurfin samfurin. An sami irin wannan sakamakon a cikin 13, 26, 34, 66, 67 ta amfani da masu canza piezoelectric na waje da sonotrodes waɗanda ke ba da babban ƙarfin duban dan tayi a cikin kayayyaki daban-daban ciki har da Ti-6Al-4V alloy 26 da bakin karfe 34 sakamakon. Ana hasashen tsarin da zai yiwu kamar haka. Ultrasound mai ƙarfi na iya haifar da cavitation na acoustic, kamar yadda aka nuna a cikin hoton X-ray na synchrotron na ultrafast in situ. Rushewar kumfa na cavitation yana haifar da raƙuman girgiza a cikin kayan da aka narke, wanda matsin lamba na gaba ya kai kusan \(100~\text {MPa}\)69. Irin waɗannan raƙuman girgiza na iya zama da ƙarfi don haɓaka samuwar ƙwayoyin ƙarfi masu mahimmanci a cikin ruwa mai yawa, suna rushe tsarin hatsi na yau da kullun na kera ƙarin Layer-by-Layer.
A nan, mun gabatar da wata hanya da ke da alhakin gyaran tsari ta hanyar sonication mai ƙarfi. Nan da nan bayan an ƙarfafa, kayan yana cikin babban zafin jiki kusa da wurin narkewa kuma yana da ƙarancin matsin lamba na yawan amfanin ƙasa. Raƙuman ultrasonic masu ƙarfi na iya haifar da kwararar filastik don canza tsarin hatsi na kayan zafi, kawai an ƙarfafa. Duk da haka, bayanan gwaji masu inganci kan dogaro da zafin jiki na matsin lamba na yawan amfanin ƙasa suna samuwa a \(T\lesssim 1150~\text {K}\) (duba Hoto na 8). Saboda haka, don gwada wannan hasashe, mun yi kwaikwayon yanayin kwayoyin halitta (MD) na abun da ke ciki na Fe-Cr-Ni mai kama da ƙarfe AISI 316 L don kimanta halayen matsin lamba na yawan amfanin ƙasa kusa da wurin narkewa. Don ƙididdige matsin lamba na yawan amfanin ƙasa, mun yi amfani da dabarar sassauta damuwa ta MD da aka bayyana a cikin 70, 71, 72, 73. Don lissafin hulɗar interatomic, mun yi amfani da Tsarin Atomic da aka Haɗa (EAM) daga 74. An yi kwaikwayon MD ta amfani da lambobin LAMMPS 75,76. Za a buga cikakkun bayanai game da kwaikwayon MD a wani wuri. Sakamakon lissafin MD na An nuna damuwa ta yawan amfanin ƙasa a matsayin aikin zafin jiki a cikin Hoto na 8 tare da bayanan gwaji da ake da su da sauran kimantawa77,78,79,80,81,82.
Matsi na samar da ƙarfi ga ƙarfe mai daraja 316 na austenitic da kuma tsarin samfurin idan aka kwatanta da zafin jiki don kwaikwayon MD. Gwaje-gwajen da aka yi daga nassoshi: (a) 77, (b) 78, (c) 79, (d) 80, (e) 81.refer to.(f)82 wani samfurin gwaji ne na dogaro da yanayin zafi na yawan amfanin ƙasa don auna damuwa a layi yayin ƙera ƙarin kayan aiki ta hanyar laser. Sakamakon manyan gwaje-gwajen MD a cikin wannan binciken an nuna su azaman \(\vartriangleleft\) don lu'ulu'u ɗaya mara lahani mara lahani da \(\vartriangleright\) don ƙananan hatsi idan aka yi la'akari da matsakaicin girman hatsi ta hanyar alaƙar Hall-Petch Girman \(d = 50~\upmu \text {m}\).
Ana iya ganin cewa a \(T>1500~\text {K}\) matsin lambar amfanin ƙasa ya faɗi ƙasa da \(40~\text {MPa}\). A gefe guda kuma, ƙiyasin ya annabta cewa girman ultrasonic da laser ya samar ya wuce \(40~\text {MPa}\) (duba Hoto na 4b), wanda ya isa ya haifar da kwararar filastik a cikin kayan zafi da aka taurare.
An yi bincike kan samuwar ƙaramin tsarin ƙarfe na austenitic 12Cr18Ni10Ti (AISI 321H) a lokacin SLM ta hanyar gwaji ta amfani da tushen laser mai rikitarwa mai daidaitawa.
An gano raguwar girman hatsi a yankin narkewar laser saboda ci gaba da narkewar laser bayan wucewa 1, 3 ko 5.
Tsarin macroscopic yana nuna cewa girman da aka kiyasta na yankin inda nakasar ultrasonic zai iya tasiri sosai ga gaban ƙarfafawa ya kai har zuwa \(1~\text {mm}\).
Tsarin MD mai ƙaramin ƙarfi ya nuna cewa ƙarfin yawan amfanin ƙarfe mai austenitic AISI 316 ya ragu sosai zuwa \(40~\text {MPa}\) kusa da wurin narkewa.
Sakamakon da aka samu ya nuna wata hanya ta sarrafa ƙananan tsarin kayan aiki ta amfani da tsarin laser mai rikitarwa wanda aka daidaita kuma zai iya zama tushen ƙirƙirar sabbin gyare-gyare na dabarar SLM mai pulsed.
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