Cov nag lossis daus - hardening nickel - raws li cov alloys yog tsim los nrog cov ntsiab lus ntawm nag lossis daus - tsim cov ntsiab lus (xws li Al, Ti, Nb) hauv lawv cov muaj pes tsawg leeg. Cov txheej txheem kev laus tau muab faib ua ob theem tseem ceeb:
Kev kho mob ua ntej: Cov hlau yog rhuab mus rau qhov kub siab (feem ntau 980-1150 degree) thiab tuav rau ib lub sijhawm. Qhov no tso cai rau nag lossis daus - tsim cov ntsiab lus kom yaj zoo ib yam rau hauv cov npib tsib xee - raws FCC lattice, tsim cov tshuaj supersaturated. Tom qab ntawd, kev ua kom txias sai sai (dej quenching lossis cua txias) yog nqa tawm los tiv thaiv cov nag lossis daus ntawm theem ob ntawm chav tsev kub, tswj cov metastable supersaturated lub xeev ntawm cov khoom tov.
Tom qab kev laus kev kho mob: Cov tshuaj supersaturated yog rhuab mus rau nruab nrab kub (feem ntau 600-850 degree) thiab tuav rau ob peb mus rau kaum ob teev. Ntawm qhov ntsuas kub no, cov kua dej ntawm nag lossis daus - tsim cov ntsiab lus hauv npib tsib xee txo qis heev. Lub supersaturated atoms (Al, Ti, Nb) yuav diffuse thiab aggregate nyob rau hauv lub matrix, thiab react nrog nickel atoms rau tsim.xaj intermetallic compound theem(cov feem ntau yog 'theem Ni₃(Al, Ti) thiab 'theem Ni₃Nb). Cov theem no yog coherent los yog semi - coherent nrog lub matrix interface, uas tuaj yeem cuam tshuam kev txav ntawm kev txav thiab yog li txhim kho lub zog tensile ntawm alloy.
Kev txhim kho lub zog tensile los ntawm kev laus kev kho mob yog ua tiav los ntawm peb qhov kev cuam tshuam hauv qab no - thaiv cov teebmeem:
Lub lattice parameters ntawm 'thiab' theem sib txawv me ntsis ntawm cov nickel - raws matrix. Thaum cov theem no ntxiv dag zog rau hauv lub matrix, lub hauv paus elastic strain teb yuav raug tsim nyob ib ncig ntawm cov theem. Thaum lub dislocation txav nyob rau hauv lub matrix, nws yuav tsum tau kov yeej cov kuj ntawm lub strain teb, uas ua rau kom lub deformation tsis kam ntawm cov alloy thiab yog li txhim kho lub tensile zog. Qhov me me ntawm qhov me me ntawm lub zog ntxiv, qhov sib txawv ntawm qhov kev faib tawm ntau dua, thiab qhov muaj zog ntawm cov kab mob hauv cheeb tsam.
Thaum qhov luaj li cas ntawm lub zog theem particles nce mus txog ib theem (feem ntau 10-50 nm), dislocations tsis tuaj yeem txiav los ntawm cov hais thiab tsuas yog hla lawv, tawm hauv dislocation loops nyob ib ncig ntawm cov hais. Kev tsim ntawm cov voj voog no yuav tsum muaj lub zog ntxiv, uas ua rau muaj kev nyuaj ntawm kev txav mus los thiab ntxiv dag zog rau lub zog ntawm cov hlau. Rau siab - kub npib tsib xee - raws li alloys, qhov no mechanism plays lub luag hauj lwm tseem ceeb nyob rau hauv nruab nrab - kub aging theem.
Thaum lub sij hawm kev laus kho mob, cov kab ntawm cov ntsiab lus carbide (xws li C) nyob rau hauv cov hlau kuj tseem yuav ua rau cov qoob loo ciam teb los tsim cov khoom zoo carbide (xws li TiC, NbC). Cov khoom no tuaj yeem pin cov ciam teb nplej, tiv thaiv kev zawv zawg ntawm cov ciam teb thaum lub sij hawm txheej txheem tensile, thiab zam kev puas tsuaj ntawm intergranular. Nyob rau tib lub sijhawm, cov kab lus xws li B thiab Zr ntxiv rau cov hlau yuav sib cais ntawm cov ciam teb nplej, txhim kho lub zog sib txuas ntawm cov ciam teb nplej thiab tsis ncaj qha rau kev txhim kho lub zog tensile.
Cov nyhuv ntawm kev laus kev kho mob ntawm lub zog tsis yog ib qho yooj yim linear kev sib raug zoo, tab sis yog ze ze rau qhov kub thiab txias thiab tuav lub sij hawm:
Kev laus kub: Yog tias qhov kub thiab txias qis dhau lawm, qhov diffusion ntawm atoms qeeb, thiab nag lossis daus ntawm cov theem ntxiv tsis txaus, ua rau muaj zog tsawg; Yog hais tias qhov kub thiab txias siab dhau lawm, lub zog ntawm cov khoom yuav loj hlob sai heev (coarsening), qhov sib txuam nrog cov matrix yuav ploj mus, cov nyhuv strain yuav tsis muaj zog, thiab lub zog yuav txo qis.
Tuav lub sijhawm: Nrog rau kev ncua sij hawm tuav, cov nag lossis daus ntawm cov theem ntxiv nce ntxiv ua ntej thiab tom qab ntawd zoo li saturated. Lub sijhawm tuav ntev ntev yuav ua rau particle coarsening thiab txo cov nyhuv ntxiv dag zog.
Noj Inconel 718 alloy ua piv txwv, qhov pom kev laus feem ntau yogob - theem kev laus: cua sov rau 720℃rau 8 h, txias rau 620℃ntawm tus nqi ntawm 55℃/ h, thiab tuav rau 8 h. Tom qab qhov kev kho mob no, ntau qhov kev nplua 'theem yog precipitated hauv matrix, thiab nws lub zog tensile tuaj yeem ncav cuag ntau tshaj 1300 MPa, uas yog 2-3 npaug ntawm lub xeev li - quenched.
Nws yuav tsum tau muab sau tseg tias kev laus ntxiv dag zog rau tsuas yog siv tau raunag lossis daus - hardening nickel - raws li alloysmuaj nag lossis daus - tsim cov ntsiab lus. Rau kev daws teeb meem - hardening npib tsib xee - raws li alloys (xws li Hastelloy C276, Alloy 600) tsis muaj Al, Ti thiab Nb, kev laus kev kho mob tsis tuaj yeem ua rau cov theem ntxiv, yog li nws tsis tuaj yeem txhim kho lawv lub zog tensile. Tsis tas li ntawd, cov txheej txheem kev laus yuav txo qis cov yas ntawm cov hlau me ntsis thaum txhim kho lub zog, yog li cov txheej txheem kev laus yuav tsum tau ua kom zoo raws li cov ntawv thov tiag tiag kom sib npaug zog thiab plasticity.
