Cobalt-based alloy yog ib qho nyuaj alloy uas tuaj yeem tiv taus ntau hom hnav, corrosion thiab kub oxidation. Cobalt-raws li alloys yog raws li cobalt raws li lub ntsiab tivthaiv, muaj ib tug ntau npaum li cas ntawm npib tsib xee, alloying tshuaj xws li chromium, tungsten thiab ib tug me me ntawm alloying ntsiab xws li molybdenum, niobium, tantalum, titanium, lanthanum, thiab qee zaus hlau. . Raws li qhov sib txawv ntawm cov hlau, cov cobalt-raws li alloy tuaj yeem ua rau hauv vuam hlau, thiab cov hmoov tuaj yeem siv rau cov tawv tawv vuam, thermal txau, tshuaj tsuag vuam thiab lwm yam txheej txheem, thiab nws kuj tuaj yeem ua rau hauvcastings, forgings thiab hmoov metallurgy qhov chaw. Muab faib los ntawm kev siv kawg, cobalt-based alloys tuaj yeem muab faib ua cobalt-raws li hnav-tiv taus alloys, cobalt-based high-temperature alloys thiab cobalt-based solution corrosion-resistant alloys. Hauv kev ua haujlwm dav dav, lawv yog ob qho tib si hnav-tiv taus thiab kub-resistant los yog hnav-resistant thiab corrosion-resistant. Qee qhov kev ua haujlwm kuj tseem yuav xav tau qhov kub thiab txias, hnav thiab tiv thaiv corrosion tib lub sijhawm. Qhov kev ua haujlwm nyuaj dua, qhov pom tseeb dua qhov zoo ntawm cobalt-based alloys.
Cov khoom ntawm Cobalt-Based Alloys
Lub ntsiab carbides hauv cobalt-based superalloys yog MC, M23C6 thiab M6C. Nyob rau hauv cam khwb cia cobalt-raws li alloys, M23C6 yog precipitated ntawm grain ciam teb thiab dendrites thaum qeeb txias. Hauv qee cov alloys, qhov zoo M23C6 tuaj yeem tsim eutectic nrog cov matrix γ. MC carbide hais yog loj dhau mus rau ncaj qha cuam tshuam rau dislocations, yog li lub zog ntawm cov hlau tsis pom tseeb, thaum finely dispersed carbides muaj ib tug zoo ntxiv zog nyhuv. Cov carbides nyob rau ntawm ciam teb nplej (feem ntau M23C6) tuaj yeem tiv thaiv cov qoob loo ciam teb, yog li txhim kho lub zog ua haujlwm ntev. Lub microstructure ntawm cobalt-raws li superalloy HA-31 (X-40) yog ib tug dispersed strengthening theem (CoCrW) 6 C-hom carbide. Lub topological kaw packed theem uas tshwm sim nyob rau hauv ib co cobalt-raws li alloys, xws li sigma theem yog teeb meem thiab ua rau cov alloy nkig.
Lub thermal stability ntawm carbides nyob rau hauv cobalt-raws li alloys yog zoo. Thaum qhov kub thiab txias, qhov kev loj hlob ntawm carbide tsub zuj zuj yog qeeb dua qhov kev loj hlob ntawm γ theem nyob rau hauv cov nickel-raws li alloy, thiab qhov kub ntawm re-solving rau hauv matrix kuj siab dua (txog 1100 ° C) . Yog li ntawd, thaum kub nce, cov cobalt-based alloy Lub zog ntawm cov hlau feem ntau txo qis. Cobalt-raws li alloys muaj zoo thermal corrosion kuj. Yog vim li cas yog vim li cas cobalt-raws li alloys yog superior rau npib tsib xee-raws li alloys nyob rau hauv no hwm yog hais tias lub melting point ntawm cobalt sulfide (xws li Co-Co4S3 eutectic, 877 ℃) yog siab tshaj cov nickel (piv txwv li, Ni-Ni3S2 eutectic. (645 ° C) yog siab, thiab diffusion tus nqi ntawm sulfur nyob rau hauv cobalt yog tsawg tshaj li nyob rau hauv nickel thiab vim hais tias feem ntau cobalt-based alloys muaj cov ntsiab lus chromium ntau dua li cov nickel-based alloys, lawv tuaj yeem tsim cov txheej txheem tiv thaiv ntawm alkali hlau sulfate (xws li Cr2O3 tiv thaiv txheej uas yog corroded los ntawm Na2SO4) ntawm qhov chaw ntawm cov hlau, txawm li cas los xij, oxidation tsis kam cobalt-based alloys feem ntau qis dua li ntawm cov nickel-based alloys.
Sib txawv ntawm lwm cov superalloys, cobalt-based superalloys tsis tau ntxiv dag zog los ntawm kev txiav txim nag lossis daus theem ruaj khov rau hauv matrix, tab sis yog tsim los ntawm austenite fcc matrix uas tau ua kom muaj zog ntxiv thiab me me ntawm carbides faib rau hauv matrix. Casting cobalt-based superalloys tso siab rau carbide ntxiv dag zog. Ntshiab cobalt crystals muaj hexagonal kaw packed (hcp) siv lead ua qauv hauv qab 417 ° C, uas hloov mus rau fcc ntawm qhov kub siab dua. Txhawm rau kom tsis txhob muaj qhov hloov pauv no thaum siv cov cobalt-based superalloys, xyaum tag nrho cov cobalt-raws li alloys yog alloyed nrog npib tsib xee kom stabilize cov qauv ntawm chav tsev kub mus rau melting point kub. Cobalt-raws li alloys muaj ib qho kev sib raug zoo ntawm kev ntxhov siab-kub, tab sis qhia superior thermal corrosion kuj ntawm qhov kub siab tshaj 1000 ° C dua li lwm qhov kub.
Kub Hreatment ntawm Cobalt-based Alloys
Qhov loj thiab kev faib tawm ntawm carbide hais thiab grain loj nyob rau hauv cobalt-raws li alloys yog rhiab heev rau covtxheej txheem casting. Yuav kom ua tiav qhov yuav tsum tau ua kom muaj zog thiab thermal qaug zog ntawm cam khwb cia cobalt-based alloy casting qhov chaw, cov txheej txheem casting yuav tsum tau tswj. Cobalt-based alloys xav tau kev kho cua sov, feem ntau los tswj cov nag lossis daus ntawm carbide. Rau cam khwb cia cobalt-raws li alloys, ua ntej nqa tawm high-temperature solid tov kev kho mob, feem ntau ntawm ib tug kub ntawm txog 1150 ° C, kom tag nrho cov thawj carbides, nrog rau ib co MC-hom carbides, yog yaj nyob rau hauv cov khoom tov; Tom qab ntawd, kev kho kev laus yog nqa tawm ntawm 870-980 ° C. Ua kom carbides precipitate dua.
Cov Qib Feem Ntau ntawm Cobalt-based Alloys
Cov qib zoo ntawm cov cobalt-raws li kub kub alloys yog: 2.4778 (raws li DIN EN 10295) Hayness 188, Haynes 25 (L-605), Alloy S-816, UMCo-50, MP-159, FSX-414, X -40, Stellite 6B, Qib 31, thiab lwm yam., Suav hom yog: GH5188 (GH188), GH159, GH605, K640, DZ40M thiab hais txog.
Kev siv ntawm Cobalt-based Alloy Castings
Feem ntau, cobalt-raws li superalloys tsis muaj coherent ntxiv dag zog rau theem. Txawm hais tias lub zog ntawm qhov kub nruab nrab yog qis (tsuas yog 50-75% ntawm cov nickel-raws li alloys), lawv muaj lub zog ntau dua, zoo thermal qaug zog tsis kam, tsis kam tiv taus, zoo dua weldability thiab thermal corrosion kuj siab tshaj qhov kub ntawm 980 ° C. Yog li ntawd, cobalt-raws li alloy castings yog tsim nyog rau kev qhia vanes thiab nozzle qhia vanes rau aviation dav hlau cav, muaj roj turbines, naval gas turbines, thiab diesel cav nozzles, thiab lwm yam.
Post lub sij hawm: May-05-2021