Tungsten thiab nws cov alloys tuaj yeem ua tiav los ntawm cov pa roj tungsten-arc vuam,
gas tungsten-arc braze welding, electron beam vuam thiab los ntawm tshuaj vapor deposition.

Weldability ntawm tungsten thiab ib tug xov tooj ntawm nws alloys consolidated los ntawm arc casting, hmoov metallurgy, los yog tshuaj-vapor deposition (CVD) cov tswv yim tau soj ntsuam. Feem ntau ntawm cov khoom siv nominally 0.060 nyob rau hauv. Cov txheej txheem sib koom ua haujlwm yog (1) roj tungsten-arc vuam, (2) roj tungsten-arc braze vuam, (3) electron beam vuam thiab (4) koom nrog CVD.
Tungsten tau ua tiav welded los ntawm tag nrho cov txheej txheem no tab sis lub suab ntawm cov welds tau cuam tshuam los ntawm cov hom ntawm lub hauv paus thiab muab tub lim (piv txwv li hmoov lossis arc-cam khwb cia khoom). Piv txwv li, welds nyob rau hauv arc-cam khwb cia cov ntaub ntawv yog comparatively tsis muaj porosity whereas welds nyob rau hauv hmoov metallurgy cov khoom yog feem ntau ntxeem tau, tshwj xeeb tshaj yog nyob rau hauv lub fusion kab. Rau cov roj tungsten-arc (GTA) welds nyob rau hauv 1/1r, nyob rau hauv. unalloyed tungsten daim ntawv, ib tug yam tsawg kawg nkaus preheat ntawm 150 ° C (uas tau pom tias yog lub ductileto-brittle hloov kub ntawm lub hauv paus hlau) ua welds tsis muaj kab nrib pleb. Raws li lub hauv paus hlau, tungsten-rhenium alloys tau weldable yam tsis muaj preheat, tab sis porosity kuj yog ib qho teeb meem nrog tungsten alloy hmoov khoom. Preheating tshwm sim tsis cuam tshuam rau weld porosity uas yog feem ntau ua haujlwm ntawm hom hlau puag.
Cov ductile-to-brittle hloov ternperatures (DBIT) rau cov roj tungsten-arc welds nyob rau hauv ntau hom hmoov metallurgy tungsten yog 325 txog 475 ° C, piv rau 150. C rau lub hauv paus hlau thiab ntawm 425 ° C rau electron beamwelded arc-cam khwb cia tungsten.
Braze welding ntawm tungsten nrog cov khoom sib txawv ntawm cov hlau tsis sib xws tsis tau tsim cov khoom sib koom ua ke zoo dua li lwm txoj kev sib koom. Peb tau siv Nb, Ta, W-26% Re, Mo thiab Re ua cov hlau muab tub lim hauv cov braze welds. Nb thiab Mo ua rau tawg loj heev.

Koom nrog CVD ntawm 510 txog 560 ° C

tshem tawm tag nrho tab sis ib qho me me ntawm porosity thiab tseem tshem tawm cov teeb meem cuam tshuam nrog qhov kub siab uas tsim nyog rau kev vuam (xws li cov nplej loj hauv qhov chaw weld thiab tshav kub-tshuaj lom).
Taw qhia
tungsten thiab tungsten-base alloys raug txiav txim siab rau ntau qhov kev siv nuclear thiab qhov chaw siab heev, suav nrog cov khoom siv hloov pauv hloov pauv, hloov tsheb rov qab, cov roj kub kub thiab lwm yam khoom siv hluav taws xob. Qhov zoo ntawm cov ntaub ntawv no yog lawv cov kev sib txuas ntawm qhov kub thiab txias heev, muaj zog zoo ntawm qhov kub siab, siab thermal thiab hluav taws xob conductivities thiab txaus tiv thaiv corrosion nyob rau hauv tej qhov chaw. Txij li thaum brittleness txwv lawv cov fabricability, qhov muaj txiaj ntsig ntawm cov khoom siv hauv cov khoom siv hauv cov kev pabcuam nruj heev nyob ntawm kev txhim kho cov txheej txheem vuam los muab cov pob qij txha uas sib piv rau cov khoom hauv lub hauv paus hlau. Yog li, lub hom phiaj ntawm cov kev tshawb fawb no yog (1) txiav txim siab lub zog ntawm cov pob qij txha uas tsim los ntawm kev sib koom ua ke hauv ntau hom unalloyed thiab alloyed tungsten; (2) ntsuas qhov cuam tshuam ntawm ntau yam kev hloov kho hauv kev kho cua sov thiab kev sib koom ua ke; thiab (3) ua kom pom qhov ua tau ntawm kev tsim cov khoom siv xeem tsim nyog rau cov ntawv thov tshwj xeeb.
Khoom siv
Unalloyed tungsten m10 m. cov nplooj ntawv tuab yog cov khoom siv ntawm kev txaus siab. Lub unalloyed tungsten nyob rau hauv txoj kev tshawb no yog tsim los ntawm hmoov metallurgy, arc casting thiab chemical-vapor deposition techniques. Table 1 qhia cov impurity theem ntawm cov hmoov metallurgy, CVD thiab arc-cam khwb cia tungsten khoom raws li tau txais. Feem ntau ntog nyob rau hauv qhov chaw nominally pom nyob rau hauv tungsten

tab sis nws yuav tsum tau muab sau tseg tias CVD cov ntaub ntawv muaj ntau tshaj li cov norma] cov fluorine.
Ntau qhov ntau thiab tsawg thiab cov duab ntawm tungsten thiab tungsten alloys tau koom rau kev sib piv. Feem ntau ntawm lawv yog cov hmoov metallurgy cov khoom txawm hais tias qee cov ntaub ntawv arc-cam khwb cia kuj tau welded. Cov kev teeb tsa tshwj xeeb tau siv los txiav txim qhov ua tau ntawm lub tsev thiab cov khoom siv. Tag nrho cov matenals tau txais nyob rau hauv ib tug tag nrho txias ua hauj lwm tej yam kev mob nrog rau cov kev zam ntawm CVD tungsten, uas tau txais raws li-deposited. Vim hais tias ntawm qhov nce brittleness ntawm recrystallized thiab loj-grained tungsten cov khoom tau welded nyob rau hauv kev ua hauj lwm mob kom txo tau cov qoob loo loj hlob nyob rau hauv lub tshav kub. B vim yog tus nqi siab ntawm cov khoom siv thiab cov khoom me me muaj, peb tsim cov qauv kuaj uas siv cov khoom siv tsawg kawg nkaus kom tau txais cov ntaub ntawv xav tau.
Txheej txheem
Txij li thaum lub ductile-to-brittle hloov kub (DBTT) ntawm tungsten yog siab tshaj chav tsev kub, tshwj xeeb yuav tsum tau siv nyob rau hauv tuav thiab machining kom tsis txhob tawg 1. Shearing ua rau ntug tawg thiab peb tau pom tias kev sib tsoo thiab electrodischarge machining tawm thaum tshav kub kub xyuas ntawm qhov chaw. Tshwj tsis yog tias lawv raug tshem tawm los ntawm lapping, cov kab nrib pleb no tuaj yeem nthuav tawm thaum lub sij hawm vuam thiab siv tom ntej.
tungsten, zoo li tag nrho cov hlau refractory, yuav tsum tau welded nyob rau hauv ib qho chaw ntshiab heev ntawm cov roj inert (gas tungsten-arc txheej txheem) los yog lub tshuab nqus tsev (electron beam pro:::ess) 2 kom tsis txhob muaj kab mob ntawm cov weld los ntawm interstitials. Txij li thaum tungsten muaj qhov siab tshaj plaws melting point ntawm tag nrho cov hlau (3410 ° C), cov khoom siv vuam yuav tsum muaj peev xwm tiv taus qhov kub thiab txias.

Table 1

Peb txheej txheem vuam sib txawv tau siv: roj tungsten-arc vuam, roj tungsten-arc braze vuam thiab electron beam vuam. Vuam tej yam kev mob tsim nyog rau ua kom tiav pcnetration ntawm qhov tsawg kawg nkaus lub zog input tau txiav txim rau txhua yam khoom. Ua ntej welding, daim ntawv cov ntaub ntawv yog machined rau hauv 囚in. dav blanks thiab degreased nrog ethyl cawv. Kev sib koom tsim yog ib qho square groove uas tsis muaj cag qhib.
Gas Tungsten-Arc vuam
Tag nrho cov automatie thiab phau ntawv roj tungsten-arc welds tau ua nyob rau hauv ib lub ehamher uas tau khaws cia hauv qab 5 x kuv los yog. Torr rau li 1 teev thiab tom qab ntawd rov qab nrog argon ntshiab heev. Raws li pom nyob rau hauv Fig. lA, lub chamber tau haum nrog ib tug traversing mechanism thiab torch lub taub hau rau tsis siv neeg vuam. Lub workpiece yog tuav nyob rau hauv ib tug tooj liab fixture muab nrog tungsten inserts nyob rau hauv tag nrho cov ntsiab lus ntawm kev sib cuag los tiv thaiv nws los ntawm brazed mus rau lub chaw ua hauj lwm los ntawm lub vuam tuav. Lub hauv paus ntawm qhov khoom siv no tau nyob hauv lub tshuab hluav taws xob lub tshuab hluav taws xob uas ua ntej ua haujlwm rau qhov xav tau qhov kub thiab txias, Fig. 1 B. Tag nrho cov welds tau ua los ntawm kev khiav ceev ntawm 10 ipm, eurrent txog 350 amp thiab voltage ntawm 10 mus rau 15 v. .
Gas Tungsten-Ac Braze Vuam
Gas tungsten-yog braze welds tau ua nyob rau hauv ib lub ehamber nrog ib tug inert cua los ntawm cov tswv yim zoo li

cov uas tau piav saum toj no. Cov hlaws-onplate braze welds ua nrog tungsten thiab W-26% Re muab tub lim hlau tau ua manually; Txawm li cas los xij, lub pob tw braze welds tau welded cia li tom qab muab cov hlau muab tso rau hauv lub pob tw.
Electron Beam Vuam
Lub eleetron beam welds tau tsim nyob rau hauv lub tshuab 150-kV 20-mA. Lub tshuab nqus tsev ntawm li 5 x I o-6 torr tau khaws cia thaum vuam. Electron beam welding ua rau muaj qhov sib piv siab ntawm qhov tob rau qhov dav thiab qhov chaw nqaim tshav kub cuam tshuam.
』oining los ntawm Chemical Vapor Disposition
Cov pob qij txha tungsten tau tsim los ntawm kev tso cov hlau tsis muaj tungsten muab tub lim los ntawm cov txheej txheem tshuaj vapor deposition3. Tungsten tau tso los ntawm hydrogen txo ntawm tungsten hexafluoride raws li cov tshuaj tiv thaiv-t
kub
WFs(g) + 3H,(g)一–+W(s) + 6HF(g).
Kev siv cov txheej txheem no rau kev koom ua ke yuav tsum tau hloov me ntsis hauv cov khoom siv thiab cov khoom siv reactant ntws. Lub ntsiab kom zoo dua ntawm cov txheej txheem no tshaj li ntau cov pa txoj kev ntawm kev koom tes yog hais tias, txij li thaum lub qis kub ua hauj lwm (510 mus rau 650 ° C) yog tsawg tshaj li qhov melting point.

tungsten (3410 ° C), recrystallization thiab ua tau ntxiv cmbrittlement ntawm wrought tungsten puag hlau los ntawm impurities los yog grain loj hlob yog tsawg.
Ntau qhov kev sib koom ua ke nrog rau lub pob tw thiab lub raj-kawg kaw tau tsim. Deposition tau ua nrog kev pab ntawm ib tug tooj liab mandrel uas yog siv los ua ib tug fixture, alignment piece thiab substrate. Tom qab kev tso dej tiav lawm, eopper mandrel raug tshem tawm los ntawm etching. Txij li thaum lwm yam kev ua haujlwm" tau qhia tias CVD tungsten muaj cov kev ntxhov siab seem uas tau tso tseg, cov pob qij txha no yog kev ntxhov siab relicvcd I hr ntawm 1000 ° txog 1600 ° C ua ntej machining lossis kuaj.
Kev tshuaj xyuas thiab kuaj
Cov pob qij txha tau kuaj pom qhov muag thiab los ntawm cov kua dej nkag mus thiab radiography ua ntej lawv raug kuaj. Cov welds raug tshuaj ntsuam xyuas rau cov pa oxygen thiab nitrogen (Table 2) thiab kev kuaj xyuas metallographic dav siv thoob plaws hauv txoj kev tshawb no.
Vim nws qhov yooj yim thiab yoog raws rau cov qauv me me, qhov kev sim khoov tau siv los ua qhov tseem ceeb rau kev sib koom ua ke thiab kev sib piv ntawm cov txheej txheem. Kev hloov pauv ntawm qhov kub thiab txias tau txiav txim siab nrog peb lub ntsiab lus dabtsi yog khoov rau cov pob qij txha ob leeg li-welded thiab tom qab laus. Cov qauv yooj yim rau kev ntsuas khoov yog qhov longitudinal

ntsej muag khoov, 24t ntev los ntawm 12t dav, qhov twg t yog cov qauv tuab. Cov qauv tau txais kev txhawb nqa ntawm 15t ncua thiab khoov nrog lub plunger ntawm lub vojvoog 4t ntawm tus nqi ntawm 0.5 ipm. Qhov no geometry tended rau normalize cov ntaub ntawv tau ntawm ntau yam thicknesses ntawm cov ntaub ntawv. Cov qauv no feem ntau yog bent transverse mus rau weld seam (longitudinal bend specimen) los muab cov qauv deformation ntawm weld, tshav kub cuam tshuam thiab cov hlau puag; Txawm li cas los xij, ob peb tus qauv tau khoov raws li qhov vuam seam (transverse bend specimen) rau kev sib piv. Lub ntsej muag khoov tau siv nyob rau hauv thawj feem ntawm kev tshawb nrhiav; Txawm li cas los xij, vim tias qhov me me ntawm qhov pom ntawm faees ntawm feem ntau cov welds vim qhov hnyav ntawm cov hlau molten, cov hauv paus khoov tau hloov pauv hauv kev sim tom qab. Cov lus pom zoo ntawm Pawg Thawj Saib Xyuas Khoom Siv 6 ntsig txog kev ntsuas khoov ntawm daim ntawv kuaj tau ua raws li qhov ua tau. Vim yog cov khoom siv tsawg, cov qauv me me tshaj plaws tau raug xaiv.
Txhawm rau txiav txim siab qhov hloov pauv qhov kub thiab txias, cov cuab yeej khoov tau muab ntim rau hauv lub qhov cub uas muaj peev xwm nce qhov kub ntawm 500 ° C. Ib qho khoov ntawm 90 mus rau 105 deg yog eonsidered tag nrho khoov. DBTT tau txhais tias yog qhov ntsuas kub qis tshaj plaws uas cov speeimen khoov tag nrho yam tsis muaj craeking. Txawm hais tias qhov kev ntsuam xyuas tau ua nyob rau hauv huab cua, kev hloov xim ntawm cov qauv tsis pom tseeb txog thaum ntsuas kub txog 400 ° C.

Daim duab 1

Cov txiaj ntsig rau Unalloyed tungsten
General Weldability
Gas Turzgstea-Arc Welding-In gas tungsten-arc vuam ntawm 1 乍in. tuab daim ntawv tsis muaj hlau, kev ua haujlwm yuav tsum tau ua kom muaj kev kub ntxhov kom tiv thaiv kev ua tsis tiav hauv kev ntxhov siab vim los ntawm thermal shock. Daim duab 2 qhia txog kev puas tsuaj uas tsim los ntawm kev vuam yam tsis muaj preheating. Cov qoob loo loj loj thiab cov duab ntawm qhov chaw weld thiab heataffected tsam yog tshwm sim hauv qhov tawg. Kev soj ntsuam ntawm preheating ternperatures los ntawm chav tsev kub mus rau 540 ° C pom tau hais tias preheating mus rau qhov tsawg kawg nkaus ntawm 150 ° C yog tsim nyog rau ib tug zoo sib xws ntawm ib tug dhau pob tw welds uas tsis muaj kab nrib pleb. Qhov ntsuas kub no sib haum rau DBTI ntawm lub hauv paus hlau. Preheating mus rau qhov kub siab dua tsis pom tias tsim nyog hauv cov kev sim no tab sis cov khoom siv nrog DBTI siab dua, lossis kev teeb tsa uas muaj kev ntxhov siab ntau dua lossis ntau qhov chaw loj, yuav xav tau preheating rau ntau dua ternperatures.
Qhov zoo ntawm cov khoom siv vuam yog nyob ntawm cov txheej txheem siv hauv fabricating lub hauv paus hlau. Autogenous welds nyob rau hauv arc-cam khwb cia tungsten yog qhov tseem ceeb tsis muaj porosity, Fig.
3A, tab sis welds nyob rau hauv hmoov metallurgy tungsten yog tus cwj pwm los ntawm tag nrho cov porosity, daim duab 3 (b), tshwj xeeb tshaj yog nyob rau hauv fusion kab. Tus nqi ntawm no porosity, Fig. 3B, tshwj xeeb tshaj yog nyob rau hauv 3C, nyob rau hauv welds ua nyob rau hauv ib tug proprietary, tsawg porosity khoom (GE-15 ua los ntawm General Electric Co., Cleveland).
Gas tungsten-arc welds nyob rau hauv CVD tungsten muaj qhov txawv txav ntawm tshav kub-cuam tshuam cheeb tsam vim lub grain qauv 0£ lub hauv paus metaF. Daim duab 4 qhia lub ntsej muag thiab sib thooj ntu ntawm cov roj tungsten-arc taub qab vuam. Nco ntsoov tias cov nplej nplua nuj ntawm cov substrate nto tau loj hlob vim qhov kub ntawm vuam. Kuj pom tseeb yog qhov tsis muaj kev loj hlob ntawm cov loj columnar

nplej. columnar nplej muaj roj
bubb_les ntawm grain ciam teb tshwm sim los ntawm fluorme impurities8. Yog li ntawd, yog tias
cov nplua nplej substrate nto yog tshem tawm ua ntej welding, lub weldment tsis muaj ib tug metallographically detectable tshav kub-tshem tawm tsam. Tau kawg, nyob rau hauv cov khoom siv CVD ua haujlwm (xws li extruded lossis kos tubing) thaj tsam cuam tshuam los ntawm tshav kub ntawm qhov vuam muaj qhov zoo li qub recrystallized grain qauv.
Cracks tau pom nyob rau hauv lub columnar grain ciam teb nyob rau hauv lub RAZ ntawm ob peb welds nyob rau hauv CVD tungsten. Qhov kev tawg no, qhia hauv daim duab 5, yog tshwm sim los ntawm kev tsim sai thiab kev loj hlob ntawm npuas nyob rau hauv cov qoob loo ciam teb ntawm hightemperatures9. Ntawm qhov kub siab koom nrog hauv kev vuam, cov npuas tuaj yeem noj tau ntau ntawm thaj tsam ntawm cov nplej; qhov no, ua ke nrog cov kev ntxhov siab uas tsim thaum lub caij txias, rub cov qoob loo sib nrug los ua ib qho tawg. Kev tshawb fawb txog kev tsim npuas hauv tungsten thiab lwm yam hlau deposits thaum kho cua sov qhia tau hais tias npuas tshwm sim nyob rau hauv cov hlau tso rau hauv qab no 0.3 Tm (lub homologous melting kub). Qhov kev soj ntsuam no qhia tau hais tias cov pa npuas tsim los ntawm kev sib koom ua ke ntawm cov chaw ua haujlwm thiab cov pa roj thaum lub sij hawm annealing. Nyob rau hauv cov ntaub ntawv ntawm CVD tungsten, cov roj yog tej zaum fluorine los yog ib tug fluoride compound
Electron Beam Vuam - Unalloyed tungsten yog electron beam welded nrog thiab tsis muaj preheating. Qhov xav tau rau preheat varied nrog cov qauv. Txhawm rau kom muaj kev sib txuas tsis muaj kab nrib pleb, preheating tsawg kawg rau DBTT ntawm lub hauv paus hlau yog pom zoo. Electron beam welds nyob rau hauv cov hmoov metallurgy cov khoom kuj muaj cov weld porosity hais yav tas los.

Gas Tungsten-Arc Braze Vuam 一In ib qho kev rau siab los tsim seb puas braze vuam yuav siv tau kom zoo dua, peb tau sim nrog cov roj tungstenarc txheej txheem ua braze welds ntawm hmoov metallurgy tungsten daim ntawv 、 Lub braze welds tau ua los ntawm preplacing cov muab tub lim hlau raws li. pob tw ua ntej welding. Braze welds tau tsim nrog unalloyed Nb, Ta, Mo, Re, thiab W-26% Re ua cov hlau muab tub lim. Raws li qhov xav tau, muaj qhov porosity ntawm fusion kab hauv metallographic seem ntawm tag nrho cov pob qij txha (Fig. 6) txij li cov hlau puag yog hmoov metallurgy cov khoom. Welds ua nrog niobium thiab molybdenum muab tub lim hlau tawg.
Lub hardnesses ntawm welds thiab braze welds tau muab piv los ntawm kev kawm ntawm cov hlaws-on-phaj welds ua nrog unalloyed tungsten thiab W一26% Re raws li muab tub lim hlau. Cov roj tungstenarc welds thiab braze welds tau ua manually ntawm unalloyed tungsten hmoov metallurgy cov khoom (qhov tsawg porosity, proprietary (GE-15) qib thiab ib tug raug coj mus muag qib). Welds thiab braze welds nyob rau hauv txhua yam khoom muaj hnub nyoog ntawm 900, 1200, 1600 thiab 2000 ° C rau l, 10, 100 thiab 1000 hr. Cov qauv no tau kuaj xyuas metallographically, thiab hardness traverses raug coj mus thoob lub weld, heataffected zone, thiab base hlau ob as-welded thiab tom qab tshav kub kho.

Rooj 2

Daim duab 2

Txij li cov ntaub ntawv siv nyob rau hauv txoj kev tshawb no yog hmoov metallurgy cov khoom, qhov sib txawv ntawm cov porosity muaj nyob rau hauv weld thiab braze weld deposits. Ntxiv dua thiab, cov pob qij txha ua nrog cov hmoov hlau metallurgy tungsten puag hlau muaj porosity ntau dua li cov uas ua nrog cov porosity tsawg, muaj tswv tungsten. Lub braze welds ua nrog W-26% Re muab tub lim hlau tsis muaj porosity tsawg dua li cov welds ua nrog cov hlau tsis muaj tungsten.
Tsis muaj kev cuam tshuam ntawm lub sij hawm lossis qhov kub thiab txias tau pom ntawm qhov hardness ntawm cov welds ua nrog unalloyed tungsten li muab tub lim hlau. Raws li welded, qhov hardness ntsuas ntawm cov weld thiab lub hauv paus hlau yog qhov tseem ceeb tas li thiab tsis hloov tom qab kev laus. Txawm li cas los xij, lub braze welds ua nrog W-26% Re muab tub lim hlau tau hnyav dua li tsim dua li cov hlau hauv paus (Fig. 7). Tej zaum qhov hardness siab dua ntawm W-Re br 立e weld deposit yog vim cov khoom hardening thiab/los yog muaj er theem finely faib nyob rau hauv lub solidified qauv. Daim duab tungstenrhenium theem 11 qhia tau hais tias cov cheeb tsam hauv cheeb tsam ntawm cov ntsiab lus siab rhenium tuaj yeem tshwm sim thaum lub sijhawm txias sai thiab ua rau muaj qhov nyuaj, nkig er theem hauv cov txheej txheem sib cais. Tej zaum qhov er theem tau raug nplua zoo nyob rau hauv cov nplej lossis cov ciam teb, txawm tias tsis muaj ib qho loj txaus los txheeb xyuas los ntawm kev kuaj metallographic lossis X-ray diffraction.
Hardness yog plotted raws li ib tug muaj nuj nqi ntawm kev ncua deb ntawm lub braze-weld center kab rau txawv aging kub nyob rau hauv daim duab 7A. Nco ntsoov qhov kev hloov sai sai

nyob rau hauv hardness ntawm fusion kab. Nrog rau kev laus zuj zus, qhov hardness ntawm braze weld txo kom txog thaum, tom qab 100 hr ntawm J 600 ° C, hardness yog tib yam li cov unalloyed tungsten puag hlau. Qhov sib txawv ntawm kev txo qis hardness nrog nce kub tuav muaj tseeb rau txhua lub sijhawm laus. Kev nce lub sij hawm ntawm qhov kub thiab txias tas li kuj ua rau simiJar txo qis hauv hardness, raws li qhia rau kev laus kub ntawm 1200 ° C hauv daim duab 7B.
Kev koom tes los ntawm Tshuaj Vapor Deposition-Kev koom tes ntawm tungsten los ntawm CVD cov txheej txheem tau tshawb xyuas raws li ib txoj hauv kev tsim cov welds hauv ntau cov qauv qauv. Los ntawm kev siv cov khoom siv tsim nyog thiab lub qhov ncauj qhov ntswg txhawm rau txwv kev tso tawm mus rau thaj chaw uas xav tau, CVD thiab cov hmoov hlau metallurgy tungsten nplooj tau koom ua ke thiab kaw qhov kawg ntawm tubing. Muab tso rau hauv ib lub bevel nrog ib lub kaum sab xis ntawm 90 deg ua cracking, Fig. 8A, ntawm qhov kev sib tshuam ntawm columnar nplej loj hlob los ntawm ib lub ntsej muag ntawm bevel thiab lub substrate (uas yog etched tam sim ntawd). Txawm li cas los xij, cov pob qij txha muaj kev ntseeg siab tsis muaj qhov tawg lossis tag nrho ntawm cov impurities tau txais, Fig. 8B, thaum kev sib koom ua ke tau hloov los ntawm kev sib tsoo lub ntsej muag ntawm lub hauv paus hlau mus rau ib lub vojvoog ntawm 飞in. tangent rau hauv paus ntawm weld. Txhawm rau ua kom pom ib qho kev thov ntawm cov txheej txheem no hauv kev tsim cov khoom siv roj, ob peb qhov kawg kaw tau ua hauv cov raj tungsten. Cov pob qij txha no tau xau-nruj thaum kuaj nrog helium huab hwm coj spectrorr: eter leak detector.

Daim duab 3

Daim duab 4

Daim duab 5

Mechanical Properties
Khoov Kev Ntsuam Xyuas ntawm Fusion Welds 一Ductile-to-brittle hloov curves tau txiav txim siab rau ntau yam pob qij txha hauv unalloyed tungsten. Cov nkhaus hauv daim duab 9 qhia tau hais tias DBTT ntawm ob lub hmoov metallurgy hauv paus hlau yog li kuv 50 ° C. Feem ntau, DBTT (qhov kub qis tshaj plaws uas yuav ua tau 90 mus rau 105 deg khoov) ntawm ob qho khoom siv tau nce ntau tom qab vuam. . Kev hloov pauv kub nce txog 175 ° C mus rau tus nqi ntawm 325 ° C rau cov hmoov hlau metallurgy tungsten thiab nce txog 235 ° C mus rau tus nqi ntawm 385 ° C rau qhov tsis tshua muaj porosity, cov khoom muaj tswv yim. Qhov sib txawv ntawm DBTTs ntawm cov khoom siv welded thiab unwelded tau raug ntaus nqi los ntawm cov nplej loj loj thiab muaj peev xwm rov faib cov impurities ntawm cov welds thiab cov cheeb tsam uas muaj cua sov. Cov txiaj ntsig kev ntsuam xyuas pom tau tias DBTT ntawm cov hmoov hlau metallurgy tungsten welds yog qis dua li ntawm cov khoom siv, txawm tias tom kawg muaj tsawg porosity. Qhov siab dua DBTT ntawm cov vuam nyob rau hauv qhov tsis tshua muaj porosity tungsten tej zaum yuav yog vim nws qhov loj me me, daim duab 3A thiab 3C.
Cov txiaj ntsig ntawm kev tshawb xyuas los txiav txim siab DBTT rau ntau cov pob qij txha hauv cov tungsten uas tsis muaj cov khoom siv tau raug sau tseg hauv Table 3. Cov kev ntsuas khoov tau zoo heev rau cov kev hloov pauv hauv cov txheej txheem kuaj. Hauv paus khoov tau tshwm sim ntau dua ductile tshaj lub ntsej muag khoov. Ib qho kev xaiv kom raug kev ntxhov siab tom qab vuam tshwm sim kom txo qis DBTT ntau. CVD tungsten muaj, raws li welded, qhov siab tshaj DBTT (560 ℃); tseem thaum nws tau muab 1 hr kev ntxhov siab ntawm 1000 ℃ tom qab vuam, nws DBTT poob rau 350 ℃. Kev ntxhov siab ntawm 1000 ° C tom qab vuam, nws DBTT poob rau 350 ° C. Kev ntxhov siab ntawm arc welded hmoov metallurgy tungsten rau 1 hr ntawm 18000 C txo DBTT ntawm cov khoom no los ntawm 100 ° C los ntawm tus nqi txiav txim rau nws li- welded. Kev ntxhov siab ntawm 1 hr ntawm 1000 ° C ntawm kev sib koom ua ke los ntawm CVD txoj kev ua rau qis tshaj DBTT (200 ° C). Nws yuav tsum raug sau tseg tias, thaum qhov kev hloov pauv no tau qis dua li lwm qhov kev hloov pauv kub tau txiav txim siab hauv txoj kev tshawb no, qhov kev txhim kho no tej zaum cuam tshuam los ntawm qhov qis qis (0.1 vs 0.5 ipm) siv hauv kev sim ntawm CVD pob qij txha.

Khoov Test ntawm braze welds-gas tungsten-arc braze welds ua nrog Nb. Ta, Mo, Re, thiab W-26% Re raws li cov hlau muab tub lim kuj tau khoov kuaj thiab cov txiaj ntsig tau sau tseg hauv cov lus 4. qhov ductility feem ntau tau txais nrog rhenium braze weld.

Txawm hais tias cov txiaj ntsig ntawm qhov kev tshawb fawb cursory no qhia tau hais tias cov hlau tsis sib xws tuaj yeem tsim cov pob qij txha nrog cov khoom siv kho tshuab sab hauv mus rau lub tsev ntawm homogeneous welds hauv tungsten, qee qhov ntawm cov hlau muab tub lim no yuav muaj txiaj ntsig zoo hauv kev xyaum.

Cov txiaj ntsig rau Tungsten Alloys.