Laser Beam Vuam, nrog nws qhov kev kub ceev, kev raug siab thiab cov yam ntxwv tsis sib cuag, tau siv dav hauv cov teb xws li tsheb, aerospace, thiab cov khoom siv hluav taws xob, tshwj xeeb tshaj yog qhia txog qhov zoo tshwj xeeb hauv kev sib txuas ntawm cov ntaub ntawv sib txawv. Txawm li cas los xij, cov kab nrib pleb khov kho (Solidification Cracking) tsim thaum lub sijhawm vuam yog ib qho ntawm cov teeb meem tseem ceeb uas txwv nws daim ntawv thov kev lag luam. Cov kab nrib pleb no feem ntau tshwm sim thaum kawg ntawm kev khov kho hauv thaj chaw fusion (Fusion Zone), uas tshwm sim los ntawm kev sib xyaw ua ke ntawm kev ntxhov siab thermal, kev khov kho shrinkage thiab cov kua zaj duab xis ntawm cov ciam teb nplej, txo cov khoom siv kho tshuab thiab lub neej qaug zog ntawm qhov sib koom ua ke.
1. Txoj kev tsim khoom
Lub hauv paus tseem ceeb ntawm cov kab nrib pleb khov yog nyob rau hauv cov kua dej seem ntawm cov ciam teb ntawm qhov kawg ntawm kev khov. Thaum lub sijhawm khov, lub pas dej molten raug muab faib ua peb thaj chaw: thaj chaw kua dawb, thaj chaw kua txwv, thiab thaj chaw khov, raws li pom hauv Daim Duab 1. Hauv thaj chaw kua txwv, cov kua ntws raug thaiv thiab tsis tuaj yeem them rau qhov kev ntxhov siab uas tsim los ntawm kev khov shrinkage, ua rau muaj kev sib cais ntawm ciam teb noob. Qhov piv ntawm lub zog ciam teb noob (γgb) rau lub zog sib txuas ntawm cov khoom-kua (γsl) txiav txim siab qhov ruaj khov ntawm cov kua dej: yog tias γgb < 2γsl, cov kua dej tsis ruaj khov thiab cov noob sib xyaw ua ke; ntawm qhov tod tes, cov kua dej ruaj khov thiab qhov tawg yooj yim tshwm sim.
Tsis tas li ntawd xwb, qhov kev tsim cov kab nrib pleb khov kuj muaj feem cuam tshuam nrog cov khoom siv hlau ntawm cov ntaub ntawv. Cov ntaub ntawv sib txawv muaj cov yam ntxwv khov sib txawv, xws li qhov kub ntawm qhov khov, qhov nrawm ntawm qhov khov, thiab kev faib tawm ntawm cov khoom sib xyaw, thiab lwm yam. Cov yam ntxwv no cuam tshuam rau qhov rhiab heev ntawm cov kab nrib pleb. Piv txwv li, hauv cov ntaub ntawv uas muaj ntau cov theem eutectic qis-melting-point, qhov rhiab heev ntawm cov kab nrib pleb khov yog siab dua vim tias cov theem eutectic no feem ntau yuav tsim cov zaj duab xis kua txuas ntxiv thaum lub sijhawm khov, yog li ua rau muaj kev tsim cov kab nrib pleb ntau ntxiv.
Thaum lub sijhawmcov txheej txheem vuam laser, cov kev ntsuas vuam xws li lub zog laser, qhov ceev vuam, thiab qhov loj ntawm qhov chaw kuj muaj feem cuam tshuam rau kev tsim cov kab nrib pleb khov kho. Cov kev ntsuas no cuam tshuam rau qhov nkag cua sov thiab qhov kub thiab txias thaum lub sijhawm vuam, yog li hloov pauv cov qauv khov kho thiab cov qauv noob. Piv txwv li, lub zog laser siab dua thiab qhov ceev vuam qis dua ua rau muaj cua sov nkag ntau dua thiab qeeb qeeb txias, uas txhawb kev loj hlob ntawm cov siv lead ua ke thiab ua rau muaj qhov rhiab heev ntawm qhov tawg. Ntawm qhov tod tes, lub zog laser qis dua thiab qhov ceev vuam siab dua ua rau muaj qhov nkag cua sov me dua thiab txias sai dua, pab txhawb kev tsim cov siv lead ua ke thiab txo qhov rhiab heev ntawm qhov tawg.
2. Kev ntsuas kev tswj hwm
Yuav ua li cas kom tshem tawm cov kab nrib pleb hauv cov solidificationlaser vuam, cov kws tshawb fawb tau tawm tswv yim ntau yam tswv yim, uas feem ntau tsom mus rau kev tswj cov qauv noob, kev ua kom zoo dua cov kev vuam, thiab kev txhim kho cov khoom siv. Los ntawm kev txhim kho cov qauv noob, tus lej ntawm cov ciam teb noob tuaj yeem nce ntxiv, thiab qhov concentration ntawm kev ntxhov siab concentration tuaj yeem txo qis, yog li txo qhov kev tsim ntawm cov kab nrib pleb. Cov kev tshawb fawb tau qhia tias los ntawm kev siv cov thev naus laus zis laser beam oscillation, columnar crystals tuaj yeem hloov pauv mus rau hauv cov crystals zoo equiaxed yam tsis ntxiv lwm yam khoom siv. Laser beam oscillation tuaj yeem faib lub zog laser, ua rau lub pas dej molten tsim turbulence, yog li rhuav tshem qhov kev loj hlob ntawm cov crystals columnar thiab txhawb kev tsim ntawm equiaxed crystals, raws li pom hauv Daim Duab 3. Tsis tas li ntawd, laser beam oscillation kuj tseem tuaj yeem ua rau qhov dav ntawm lub pas dej molten, txo qhov kub thiab txias gradient, thiab ntev lub sijhawm solidification ntawm lub pas dej molten, uas yog qhov zoo rau kev sib kis ntawm cov solutes thiab kev rov ua dua ntawm cov yeeb yaj kiab kua, yog li txo qhov rhiab heev ntawm cov kab nrib pleb solidification.
Kev faib tawm ntawm cov zaj duab xis kua ciam teb ntawm cov noob nyob rau hauv cov duab pas dej sib txawv.
Daim duab kos ntawm lub pas dej vuam uas yaj, a, b) tsis muaj oscillation, c, d) lateral oscillation, e, f) longitudinal oscillation, g, h) circumferential oscillation.
Ntxiv rau qhovlub teeb laserKev siv tshuab oscillation, siv ob lub laser kuj yog ib txoj hauv kev zoo los tiv thaiv cov kab nrib pleb khov. Ob lub laser tuaj yeem ua tiav kev hloov pauv los ntawm cov siv lead ua ke mus rau cov siv lead ua ke los ntawm kev ua kom lub voj voog thermal zoo dua, yog li txo cov noob me me thiab kev ntxhov siab. Piv txwv li, thaum siv CO₂ laser ua qhov chaw kub tseem ceeb thiab Nd: YAG pulsed laser ua qhov chaw kub pabcuam, lub voj voog thermal zoo dua tuaj yeem tsim thaum lub sijhawm vuam, txhawb kev tsim cov siv lead ua ke thiab txo qhov rhiab heev ntawm cov kab nrib pleb khov, raws li pom hauv Daim Duab 4.
Kev ua kom zoo dua cov kev ntsuas vuam kuj yog ib txoj hauv kev tseem ceeb los tiv thaiv cov kab nrib pleb khov. Los ntawm kev kho cov kev ntsuas xws li lub zog laser, qhov ceev vuam, thiab qhov loj ntawm qhov chaw, qhov cua sov nkag thiab qhov kub thaum lub sijhawm vuam tuaj yeem tswj tau, yog li cuam tshuam rau cov qauv khov thiab cov qauv noob. Cov kev tshawb fawb tau qhia tias kev kho ua ntej cua sov tuaj yeem txo qhov nrawm txias, txhawb kev tsim cov siv lead ua ke, thiab yog li txo qhov rhiab heev ntawm cov kab nrib pleb khov, raws li pom hauv Daim Duab 5. Tsis tas li ntawd, cov txheej txheem xws li siv pulsed laser vuam thiab nce qhov ceev vuam kuj tuaj yeem ua tiav kev hloov pauv los ntawm cov siv lead ua ke mus rau cov siv lead ua ke los ntawm kev hloov pauv qhov cua sov nkag thiab qhov txias, yog li txo qhov rhiab heev ntawm cov kab nrib pleb.
Daim Duab 5. a) Tsis tau cua sov, b) 300°C cov nplej uas tau ua kom sov ua ntej.
Thaum vuam cov khoom sib txawv nrog lasers, vim muaj qhov sib txawv ntawm cov khoom siv lub cev thiab tshuaj ntawm cov khoom siv, cov khoom sib xyaw ua ke brittle intermetallic feem ntau yuav tsim, uas yog ib qho ntawm cov laj thawj tseem ceeb ntawm kev tawg solidification. Yog li ntawd, kev kho cov txheej txheem laser thiab qhov chaw kom txo qhov tsim lossis ntau ntawm cov khoom sib xyaw intermetallic kuj yog ib qho tseem ceeb los tiv thaiv cov tawg solidification. Piv txwv li, hauv kev vuam laser ntawm cov khoom sib txawv tooj liab-aluminium, los ntawm kev tswj qhov offset ntawm lub teeb laser thiab qhov ceev vuam, qhov sib xyaw ntawm tooj liab thiab txhuas hauv lub pas dej molten tuaj yeem txo qis, yog li txo qhov tsim ntawm cov khoom sib xyaw brittle intermetallic thiab txo qhov rhiab heev ntawm cov kab nrib pleb. Tsis tas li ntawd, kev siv cov ntaub ntawv sau kuj tseem tuaj yeem txhim kho kev ua tau zoo ntawm cov pob qij txha welded thiab txo qhov tsim ntawm cov kab nrib pleb. Cov ntaub ntawv sau tuaj yeem txo qhov tsim ntawm cov khoom sib xyaw intermetallic los ntawm kev hloov pauv cov khoom sib xyaw thiab microstructure ntawm cov pob qij txha welded thiab txhim kho qhov tawv ntawm cov pob qij txha welded.
Cov kab nrib pleb khov kho yog ib qho ntawm cov teeb meem feem ntau hauv cov txheej txheem vuam laser. Lawv cov txheej txheem tsim yog qhov nyuaj thiab cuam tshuam nrog kev sib cuam tshuam ntawm ntau yam xws li cua sov, mechanics, thiab metallurgy. Los ntawm kev kawm tob txog cov txheej txheem tsim ntawm cov kab nrib pleb khov kho, lub hauv paus theoretical tuaj yeem muab rau kev tswj cov kab nrib pleb. Nyob rau hauv xyoo tas los no, cov kws tshawb fawb tau tawm tswv yim ntau txoj hauv kev los tswj cov kab nrib pleb khov kho, uas feem ntau tsom mus rau kev tswj cov qauv noob, kev ua kom zoo dua cov txheej txheem vuam, thiab kev txhim kho cov khoom siv. Kev xyaum tau ua pov thawj tias cov tswv yim no tuaj yeem txo qhov rhiab heev ntawm cov kab nrib pleb khov kho rau qee qhov thiab txhim kho qhov zoo thiab kev ntseeg siab ntawm laser vuam. Txawm li cas los xij, vim yog qhov nyuaj thiab ntau haiv neeg ntawm cov txheej txheem vuam laser, tseem muaj qee qhov tsis txaus hauv kev tshawb fawb tam sim no. Piv txwv li, rau cov txheej txheem tiv thaiv ntawm cov kab nrib pleb khov kho nyob rau hauv cov ntaub ntawv sib txawv thiab cov xwm txheej vuam, tseem xav tau kev tshawb fawb tob ntxiv.
Lub sijhawm tshaj tawm: Lub Peb Hlis-20-2025
