01 Kev Sib Tw Kawm Ntawv: Vim lawv qhov tsawg tsawg, muaj zog tshwj xeeb, thiab kev tiv thaiv corrosion zoo heev, aluminium alloys tau dhau los ua cov ntaub ntawv tseem ceeb hauv aerospace, automotive, thiab cov khoom siv hluav taws xob. Txawm li cas los xij, nrog cov kev xav tau nce ntxiv hauv kev lag luam niaj hnub rau cov geometries nyuaj thiab siab -cov khoom siv sib sib zog nqus, tsoos casting thiab machining txoj kev ntsib cov kev txwv tseem ceeb thaum tsim cov khoom uas muaj cov kab sib txuas sab hauv, cov qauv lattice, thiab nyias - cov yam ntxwv ntawm phab ntsa. Additive manufacturing technologies-tshwj xeeb yog Laser Powder Bed Fusion (LPBF) thiab Laser Directed Energy Deposition (LDED)- muab txoj hauv kev hloov pauv los kov yeej cov kev tsim khoom no. LPBF technology constructs complex components with densities exceeding 99.5% by selectively melting pre-deposited powder layers using a high-energy laser beam, building the structure layer by layer. Nrog rau cov nqi cua txias mus txog qhov kev txiav txim ntawm 10⁶ K / s, cov txheej txheem no ua rau tsim cov txheej txheem supersaturated thiab ultrafine -grained microstructures uas nyob deb dhau ntawm qhov sib npaug ntawm lub zog. Hloov pauv, LDED thev naus laus zis- uas ua haujlwm ib txhij noj cov hmoov nrog rau laser melting- ua kom pom qhov zoo ntawm kev kho cov khoom puas, kev tsim cov khoom loj - nplai cov qauv, thiab kev tsim cov khoom ua haujlwm zoo. Txawm li cas los xij, aluminium alloys ntsib ntau yam ntawm lub cev muaj zog -kev sib tw metallurgical thaum lub sij hawm laser additive manufacturing txheej txheem. Aluminium alloys nthuav tawm qhov cuam tshuam ntawm ntau dua 90% mus rau ze ntawm -infrared lasers (nrog lub wavelength ntawm 1070 nm) ntawm chav tsev kub; qhov no ua rau muaj kev sib txuas ntawm lub zog tsis tshua muaj zog, yuav tsum tau siv lub siab -lub zog- lasers ceev los tsim lub pas dej khov khov. Tsis tas li ntawd, cov ntaub ntawv ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom oxide zaj duab xis (Al₂O₃) cov ntaub ntawv tau yooj yim rau ntawm qhov chaw ntawm aluminium alloys. Nrog lub melting point ntawm 2072℃-qhov tseem ceeb siab tshaj qhov ntawm cov txhuas matrix (660 degree)-fragments ntawm no oxide zaj duab xis feem ntau tsis yaj tag nrho nyob rau hauv lub melt pas dej ua ke, nquag ua hauj lwm raws li qhov chaw nucleation rau cov kab nrib pleb thiab qhov chaw ntawm tsis muaj - ntawm {{33.}} fusion defects Qhov tseem ceeb tshaj plaws, kev solubility ntawm hydrogen hauv cov kua txhuas (kwv yees li 0.7 cm³ / 100g) yog qhov siab dua li cov khoom txhuas (kwv yees li 0.04 cm³ / 100g). Thaum lub sij hawm solidification ceev ceev, supersaturated hydrogen atoms tsis muaj sij hawm txaus los diffuse tawm; es tsis txhob, lawv sib sau ua ke ntawm cov khoom-kua interface pem hauv ntej los tsim cov pa roj npuas nuclei, thaum kawg tawm hauv qab metallurgical pores li ntawm ob peb microns mus rau kaum ntawm microns nyob rau hauv txoj kab uas hla nyob rau hauv lub solidified microstructure. Lub caij no, qhov sib txawv ntawm qhov kub thiab txias ntawm aluminium alloys (piv txwv li, tshaj 150℃rau Al7075) thiab lawv qhov tseem ceeb solidification shrinkage (kwv yees li 6%) ua rau lawv muaj kev cuam tshuam heev rau solidification porosity thiab kub tawg ib zaug cov khoom noj ntawm tus Tsov tus tw ntawm lub pas dej yaj kaw. Qhov no yog qhov kev sib tw tseem ceeb uas ntsib siab -lub zog 2xxx thiab 7xxx series aluminium alloys thaum lub sijhawm LPBF txheej txheem. Tsis tas li ntawd, lub thermal cycling yam ntxwv ntawm laser additive manufacturing- nyob rau hauv lub zos melt pas dej ua ke kub tshaj 2000℃thaum lub puag ncig hmoov thiab substrate nyob nruab nrab ntawm chav tsev kub thiab 200 degree, ua rau kub gradients siab li 10⁶ K / m- tsim ib tug complex thermal stress field nyob rau hauv lub fabricated cheeb tsam; Yog tias tsis muaj kev tswj hwm, qhov no tuaj yeem ua rau warping, deformation, thiab txawm tias inter{57}} txheej tawg.
02 Composition Design: Nyob rau theem ntawm kev tsim qauv, cov txheej txheem aluminium alloy ib txwm ua haujlwm hauv casting thiab forging feem ntau tsis tsim nyog rau kev tsim khoom ntxiv. Noj AlSi10Mg alloy ua piv txwv: thaum nws nyob ze -eutectic muaj pes tsawg leeg endows nws nrog zoo heev fluidity thaum lub sij hawm casting, nyob rau hauv lub ceev ceev solidification tej yam kev mob ntawm LPBF, lub coarse network ntawm eutectic silicon theem paradoxically ua ib qhov chaw ntawm kev nyuaj siab concentration. Tsis tas li ntawd, cov hlau alloy lub zog tensile ntawm 300℃plummets mus rau kwv yees li 10% ntawm nws chav -qhov kub thiab txias- tshwm sim los ntawm kev coarsening sai thiab tawg ntawm eutectic microstructure ntawm qhov kub siab. Yog li ntawd, txoj kev loj hlob ntawm tshwj xeeb aluminium alloy systems haum rau cov yam ntxwv tshwj xeeb ntawm additive manufacturing tau tshwm sim raws li ib tug tseem ceeb kev tshawb fawb hotspot nyob rau hauv daim teb no.
Kev tshawb fawb ua los ntawm Chongqing Institute of Green thiab Intelligent Technology, Suav Academy ntawm Kev Tshawb Fawb, qhia tias los ntawm kev ntxiv cov lej ntawm Sc (0.2–0.4 wt%) thiab Zr (0.1–0.3 wt%) rau Al-Mg-raws li alloys, nanoscale Al₃(Sc, Zr6} thawj theem ntawm L. qauv- tuaj yeem tsim * nyob rau hauv qhov chaw * thaum lub sij hawm ceev ceev solidification txheej txheem ntawm Laser Powder Bed Fusion (LPBF). Cov theem no nthuav tawm qhov tsis sib xws ntawm lattice tsis sib haum xeeb (kwv yees li 1.3%) nrog rau -Al matrix, yog li ua haujlwm tau zoo heev heterogeneous nucleation site uas ua kom cov nplej loj los ntawm kaum tawm micrometers mus rau qib -micrometer. Txoj kev tshawb fawb ntxiv sau tseg tias SLM-fabricated Al-Mg-Mn-Sc-Zr alloy nthuav tawm cov yam ntxwv bimodal grain qauv: cov npoo ntawm lub pas dej ua ke muaj qhov zoo equiaxed grain cheeb tsam nrog qhov nruab nrab cov nplej loj ntawm kwv yees li 1.04 ntawm qhov nruab nrab ntawm μm, cheeb tsam- loj hlob raws li kev tsim kho- nrog qhov nruab nrab ntawm cov nplej loj ntawm kwv yees li 2.11 μm. Qhov no heterogeneous grain qauv stems los ntawm spatial variations nyob rau hauv kub gradients thiab nucleation densities nyob rau hauv lub melt pas dej ua ke; tshwj xeeb, cov npoo ntawm lub pas dej yaj yog cov yam ntxwv ntawm qhov kub thiab txias gradients thiab kev txhawb nqa ntawm Al₃ (Sc, Zr) thawj theem, uas txhawb nqa cov nucleation heterogeneous, thaum lub pas dej yaj hauv qhov chaw ua kom pom qhov kub thiab txias gradient uas pab txhawb kev loj hlob ntawm epitaxial crystals raws li cov kev taw qhia ntawm qhov siab tshaj plaws kub dissipation. Qhov tseem ceeb, thaum Sc yog ib qho khoom kim heev (tus nqi kwv yees li $ 3,000 / kg), Zr kuj pheej yig (kwv yees li $ 30 / kg); Kev sib xyaw ua ke ntawm ob lub ntsiab lus no tsim cov tub ntxhais- plhaub qauv- suav nrog Al₃Sc core thiab Al₃Zr plhaub- uas tsis yog tsuas yog txhim kho cov thermal stability ntawm cov theem ntxiv tab sis kuj txo cov nqi tag nrho ntawm cov hlau. Lub caij no, ib pab neeg los ntawm Shanghai Jiao Tong University tau tshaj tawm lwm txoj hauv kev tsim lub tswv yim tsim los ntawm "deformable- hloov pauv eutectic nanocaffold." Xaiv qhov ze ntawm -eutectic Al-Er system (12.7 wt% Er) raws li lawv cov qauv alloy, pab pawg tau siv lub peev xwm ntawm Er los ua Al₃Er theem nrog L1₂ qauv nrog Al; Cov theem no nthuav tawm cov lattice mismatch ntawm tsuas yog 3.96% txheeb ze rau -Al matrix thiab yog tus cwj pwm los ntawm kev nplua nuj ntawm cov tshuab plam thiab lub peev xwm siab rau ntxaib. Thaum lub sij hawm LPBF luam ntawv txheej txheem, Al₃Er precipitates nyob rau hauv daim ntawv ntawm ib tug nruam, peb -dimensional nanoscale skeleton, uas yog kwv yees li 10.3 vol%. Lub cev pob txha no tsis yog tsuas yog muaj peev xwm ua kom muaj kev ntxhov siab ntau tshaj 1300 MPa tab sis kuj pab txhawb cov yas yas thaum lub sij hawm deformation los ntawm kev tsim ntawm deformation ntxaib thiab 9R ntev-lub sij hawm stacking- xaj cov qauv- yog li no hauv paus hloov pauv cov kev xav ib txwm muaj nyob rau hauv skeleton. Raws li - luam tawm Al-Er-Mg alloy (RAE700) nthuav tawm lub zog tawm ntawm 632 MPa, uas nce ntxiv mus rau 707 MPa tom qab kev kho kev laus ncaj qha, thaum tib lub sijhawm tswj qhov elongation ntawm 7-10%; cov khoom zoo tshaj plaws ntawm tag nrho cov uas tau tshaj tawm yav dhau los 3D- luam tawm aluminium alloys. Tsis tas li ntawd, ib pab neeg tshawb fawb ntawm Nagoya University tau tsim cov txheej txheem ntawm Al-Fe-Mn-Ti alloys raws li "elemental partitioning control" lub tswv yim. Los ntawm kev ntxiv Cu thiab Mn, lawv tau ua tiav qhov kev ruaj khov ntawm Al₆Fe theem- hloov pauv mus rau theem kev txhawb nqa muaj txiaj ntsig-thaum ib txhij qhia Ti, uas muab faib rau theem khoom kom ua kom cov nplej ua kom zoo dua qub (txog li 2.3 μm). Yog li ntawd, cov alloy ua tiav ib chav-kub tensile zog ntawm 390 MPa thiab ductility ntawm 14-17%; Qhov tseem ceeb, nws cov khoom siv kho tshuab tseem tsis tau hloov pauv txawm tias tom qab thermal raug ntawm 300℃rau 100 teev.
03 Kev Tswj Xyuas Txheej Txheem: Kev sib raug zoo ntawm cov txheej txheem tsis ua haujlwm thiab cov dej ntws hauv pas dej ua ke yog qhov tseem ceeb rau elucidating lub mechanisms tswj microstructure tsim nyob rau hauv laser additive manufacturing ntawm txhuas alloys. Kev coj tus cwj pwm ua kua dej hauv lub pas dej ua ke yog tsav los ntawm Marangoni convection, recoil siab, buoyancy, thiab thermocapillary rog. Ntawm cov no, Marangoni shear rog- tshwm sim los ntawm qhov nro gradients tshwm sim los ntawm qhov kub thiab txias gradients thoob plaws lub pas dej ua ke ntog- ua rau lub zog tseem ceeb tsav molten hlau ntws los ntawm lub pas dej hauv nruab nrab mus rau nws qhov chaw. Conversely, recoil siab-tsim los ntawm lub zog ejection ntawm hlau vapor nyob rau hauv lub keyhole- siv ib tug compressive quab yuam uas thawb lub molten hlau mus rau hauv qab thiab sidewalls ntawm lub keyhole. Studies indicate that volumetric energy density (VED) serves as the critical metric for determining melt pool mode transitions: when the VED exceeds approximately 60 J/mm³, the evaporative recoil pressure becomes sufficient to generate a keyhole within the melt pool with an aspect ratio greater than 1, thereby initiating the "keyhole mode"; conversely, tus txheej txheem ua hauj lwm nyob rau hauv "kev coj ua hom." Txawm hais tias hom keyhole ua kom yooj yim rau kev ua tiav ntawm cov khoom siv siab, qhov tsis ruaj khov ntawm qhov keyhole-tshwj xeeb, lub sijhawm tawg ntawm nws cov phab ntsa pem hauv ntej{13}} yog qhov tseem ceeb rau kev tsim cov keyhole porosity (qhov pores feem ntau 50-200 μm hauv txoj kab uas hla). Cov pores no yog tus cwj pwm los ntawm lawv qhov loj me thiab tsis xwm yeem morphology, ua rau muaj kev cuam tshuam loj dua rau kev ua haujlwm qaug zog dua li ua kom zoo - nplai metallurgical pores. Kev tshawb fawb ntawm Northwestern Polytechnical University tau pom tias qhov sib ntxiv ntawm qhov nyiaj (0.15 wt%) ntawm Al-Nb-B nplej refiner rau AlSi10Mg alloy tuaj yeem hloov kho qhov columnar - mus rau -equiaxed hloov (CET). Ua raws li heterogeneous nucleation qhov chaw, qhov tshwm sim NbB₂ thiab Al₃Nb hais kom nce qhov ntim feem ntawm equiaxed nplej los ntawm tsawg dua 20% mus rau ntau tshaj 80%; concurrently, qhov kev cuam tshuam no txo cov yas anisotropy piv (txhais tias yog qhov piv ntawm longitudinal rau transverse elongation) los ntawm 3.5 mus rau 1.2, yog li ua tiav ib lub xeev ntawm ze li ntawm isotropy. Lub evolutionary yam ntxwv ntawm porosity defects qhia txawv variations nyob rau hauv txawv aluminium alloy systems: nyob rau hauv Al-Cu series alloys, lub broad solidification ntau yam ua rau muaj zog txaus nyob rau hauv lub mushy cheeb tsam, rendering zoo noj (compensatory melt flow) ntau nyuaj; Yog li ntawd, qhov ntim feem ntawm metallurgical pores nyob rau hauv cov alloys tuaj yeem ncav cuag 1-2%. Hauv qhov sib piv, Al-Si series alloys-vim qhov nqaim solidification ntau yam cuam tshuam nrog lawv cov eutectic muaj pes tsawg leeg- tso cai rau qib porosity kom tswj tau zoo kom qis dua 0.1%. Kev tsim ntawm cov khoom siv lead ua zoo sib txuas nrog rau txheej txheej - los ntawm - txheej txheej solidification cwj pwm; thaum 0℃unidirectional scanning lub tswv yim yog ua haujlwm, a<001>kev ntxhib los mos tsim raws li kev tsim cov kev taw qhia, ua rau muaj qhov sib txawv ntawm 10-20% ntawm cov txiaj ntsig zoo nyob rau hauv longitudinal (tsim kev taw qhia) thiab transverse cov lus qhia. Hloov pauv, siv 67℃rotation scanning lub tswv yim tuaj yeem txo qhov kev ntxhib los mos rau ib theem ntawm kev taw qhia random, yog li qhov tseem ceeb tshem tawm anisotropy hauv cov khoom siv kho tshuab. Hais txog kev ua haujlwm siab - qhov kub thiab txias, kev tsim cov khoom siv aluminium ntxiv muaj peev xwm ua kom muaj zog ntxiv nrog rau cov teeb meem tshwj xeeb txog kev puas tsuaj ntawm cov khoom. Ib tsab xov xwm tshuaj xyuas los ntawm Central South University categorizes lub siab -kub ntxiv zog mechanisms ntawm tshav kub- resistant additively manufactured txhuas alloys rau hauv peb txoj kev tseem ceeb. Ua ntej, cov multi-cov ntsiab lus sib xyaw ua ke tsim muaj ntau- txheej, thermally ruaj khov architecture los ntawm kev sib txuas cov ntsiab lus nrog sib txawv diffusion tus nqi. Piv txwv li, hauv Al-Ce-Sc-Zr alloys, qhov ntom ntom thiab zoo li Al₁₁Ce₃ eutectic theem, ua ke nrog intragranular L1₂-Al₃(Sc, Zr) precipitates, tsim cov nyhuv dual;{1} Qhov no ua rau cov hlau tuav lub zog tensile ntawm 233 MPa ntawm 300℃thiab 142 MPa ntawm 400 degree, tsis muaj qhov tseem ceeb ntawm cov nplej coarsening pom txawm tias tom qab ntev thermal raug ntawm 400℃rau 96 teev. Thib ob, intermetallic ntxiv dag zog rau kev xaiv cov sib txuas sib txuas nrog cov sib txuas uas tsis muaj qhov sib txawv thiab cov ntsiab lus siab melting los tsim cov qauv pob txha nruj ntawm qhov kub siab. Cov coarsening tus nqi tas li ntawm Al₁₁Ce₃ theem ntawm 400℃tsuas yog 1.6 nm³/s-tseem ceeb tsawg dua li ntawm Al₂Cu theem hauv ib txwm Al-Cu alloys ntawm qhov kub thiab txias (kwv yees li 100 nm³ / s); qhov no superior siab - qhov kub thiab txias stability tso cai rau tus qub ua tsis tu ncua raws li ib tug zoo barrier rau dislocation motion. Thib peb, atomic- nplai kev cai txwv tsis pub coarsening los ntawm kev qhia cais cov ntsiab lus ntawm qhov cuam tshuam ntawm cov theem ntxiv thiab cov matrix. Cov kev tshawb fawb tau pom tias cov ntsiab lus xws li Sc, Zr, Si, thiab Mn- uas sib cais ntawm θ′-Al₂Cu/ -Al interface- tuaj yeem txo lub zog ntawm lub ntsej muag thiab cuam tshuam atomic diffusion, yog li txuas ntxiv qhov kev pabcuam kub ntawm 4 1 2 xxx℃{ ntawm 250℃thiab 300 degree. Ib txoj kev tshawb fawb luam tawm hauv *Nature Communications*- coj los ntawm Academician Lu Jian ntawm City University of Hong Kong hauv kev koom tes nrog ntau lub koom haum- tau ua ib kauj ruam tseem ceeb los ntawm kev siv cov ntsiab lus tsis huv uas pom muaj nyob hauv txhuas alloys (Si, Fe, Mn, thiab Ni) los tsim kom muaj cua sov- tiv taus Al-7.44Si-2.34Fe-1.79Mn-1.12Ni alloy uas tsis muaj cov hlau muaj nuj nqis lossis tsis tshua muaj hauv ntiaj teb. Nyob rau hauv cov xwm txheej ceev ceev, cov hlau no tsis yog- sib npaug sib cais, embedding tshav kub- tiv taus ntau- cov khoom sib txuas intermetallic nanoprecipitates- tuav ib feem ntawm txog li 14% - ntawm cov khoom siv hluav taws xob los ntawm cov cellular ruaj khov, ruaj khov ntawm cov cellular. Tsis tas yuav tsum muaj kev tshaj tawm -kev ua haujlwm, cov hlau yuav nthuav tawm ib chav -kub tensile lub zog ntawm 582 MPa, nrog lub zog ntawm 263 MPa thiab 114 MPa ntawm 300℃thiab 400 degree, raws li. Tsis tas li ntawd, txoj kev tshawb no nthuav tawm - thawj zaug hauv aluminium alloys - lub zog toughening mechanism uas tau tsav los ntawm cov khoom ntawm lub xeev amorphization: thaum lub sij hawm siab - kub deformation, ib feem ntawm cov intermetallic nanoprecipitates undergoes ib tug solid-state amorphous transformation, (L1₂-ordered '-(Ni, Fe)₃Al theem)" nanobiphasic qauv uas muab ib qho ntxiv zog dissipation txoj kev rau high-temperature crack propagation.
