Deformation strengthening (los yog strain strengthening, ua hauj lwm hardening)
Txhais
Tom qab cov khoom yields, nrog rau cov degree ntawm deformation, lub zog thiab hardness ntawm cov khoom nce, thiab cov plasticity thiab toughness txo, qhov tshwm sim yog hu ua deformation strengthening los yog ua hauj lwm hardening.
Mechanism
Nrog rau cov yas deformation, qhov dislocation ceev txuas ntxiv mus, yog li qhov dislocation nyob rau hauv lub zog ntawm kev sib nrig sib hla-txiav intensified, qhov tshwm sim uas ua rau ib tug taag txiav kauj ruam, dislocation entanglement thiab lwm yam teeb meem rau lub dislocation txav ntawm kev tiv thaiv kom nce, ua rau deformation kuj nce mus rau qhov txuas ntxiv ntawm cov yas deformation tshwm sim los ntawm cov teeb meem los txhim kho lub zog ntawm txoj cai hlau: qib ntawm deformation nce, lub zog ntawm cov khoom, hardness nce, plasticity, toughness txo, qhov dislocation ceev tseem nce ntxiv. , raws li daim duab formula, nws tuaj yeem pom tias lub zog thiab qhov sib txawv ntawm qhov ntom ntom ρ ib nrab lub zog yog proportional rau qhov dislocation, qhov loj dua Berthold vector b, qhov tseem ceeb tshaj qhov kev txhawb zog.
Cov txheej txheem
Txias deformation, xws li txias nias, tumbling, txhaj tshuaj peening, thiab lwm yam.
Piv txwv
Kev kos duab txias ntawm steel hlau nce nws lub zog exponentially.
Tswv yim tseem ceeb ntawm deformation strengthening (pros thiab cons)
(1) Qhov zoo:
① deformation ntxiv dag zog yog ib txoj hauv kev zoo los txhawb cov hlau, rau qee cov ntaub ntawv uas tsis tuaj yeem ua kom muaj zog nrog kev kho cua sov, koj tuaj yeem siv txoj kev deformation ntxiv dag zog los txhim kho lub zog ntawm cov khoom, uas tuaj yeem ua rau lub zog nce exponentially.
② yog ib qho tseem ceeb ntawm kev ua thiab molding ntawm tej yam workpieces los yog semi-tiav khoom, kom cov uniform deformation ntawm cov hlau, thiaj li hais tias cov workpiece los yog semi-tiav khoom molding ua tau, xws li txias-draw steel hlau, qhov chaw ntawm lub stamping molding.
③ deformation ntxiv dag zog tuaj yeem txhim kho kev nyab xeeb ntawm cov khoom lossis cov khoom siv hauv cov txheej txheem ntawm kev siv, qee qhov ntawm qhov chaw ntawm qhov kev ntxhov siab lossis qhov tshwm sim dhau los, yog li ntawd cov yas deformation ntawm qhov chaw, vim yog hardening ntawm deformation ntawm cov khoom overloaded. kom nres thiab yog li txhim kho kev nyab xeeb.
(2) Qhov tsis zoo
①Deformation ntxiv dag zog kuj ua rau muaj teeb meem rau kev tsim khoom thiab siv cov ntaub ntawv, deformation ua rau lub zog nce, plasticity txo, thiab txuas ntxiv deformation coj teeb meem, yuav tsum tau haus ntau zog.
(2) Txhawm rau tso cai rau cov khoom siv txuas ntxiv mus rau deform, nws yog ib qho tsim nyog yuav tsum tau ua cov recrystallization annealing nyob rau hauv nruab nrab, kom cov khoom tuaj yeem txuas ntxiv deform tsis tawg, uas ua rau cov nqi ntau lawm.
Solid Solution Strengthening
Txhais
Nrog rau qhov nce hauv cov ntsiab lus ntawm cov atom, cov khoom tov muaj zog, hardness, plasticity, toughness, lub phenomenon hu ua solid solution strengthening.
Mechanism
(1) Lub solute atoms yaj, thiaj li hais tias cov khoom tov lattice distortion, nyob rau hauv lub slip nto txav ntawm lub dislocation muaj ib tug cuam tshuam.
(2) Cov kab dislocation ntawm solute atom agglomeration ntawm Kirchner cov pa roj pab pawg tsim los ntawm dislocation ntawm pinning nyhuv, ua rau lub dislocation zog kuj.
(3) Polarization ntawm solute atoms nyob rau hauv lub laminar dislocation cheeb tsam cuam tshuam cov kev txav ntawm ncua dislocations. Txhua yam uas cuam tshuam rau kev txav mus los thiab ua rau muaj kev cuam tshuam rau kev txav txav tuaj yeem ua rau muaj zog ntxiv.
Kev cai lij choj
(i) Nyob rau hauv cov khoom tov solubility ntau, qhov ntau dua qhov loj feem ntawm cov ntsiab lus alloying, qhov ntau dua qhov ntxiv dag zog
② Qhov loj dua qhov sib txawv ntawm cov kuab tshuaj thiab cov kuab tshuaj atoms, qhov tseem ceeb tshaj qhov ua kom muaj zog.
③ qhov tsim ntawm interstitial khoom tov ntawm cov ntsiab lus ntawm lub zog ntawm cov nyhuv yog ntau dua qhov tsim ntawm cov khoom hloov cov ntsiab lus.
④ qhov ntau dua qhov sib txawv ntawm tus naj npawb ntawm valence electrons ntawm cov atoms thiab cov kuab tshuaj atoms, qhov ntau dua qhov ntxiv dag zog.
Cov txheej txheem
Alloying, piv txwv li ntxiv alloying ntsiab
Piv txwv
Lub zog ntawm tooj liab-nickel alloy yog ntau dua li ntawm cov hlau ntshiab ntawm tooj liab thiab npib tsib xee.
Fine grain ntxiv dag zog
Txhais
Nrog kev txo qis ntawm cov nplej loj, lub zog thiab hardness ntawm cov khoom nce, thiab cov plasticity thiab toughness kuj tseem txhim kho, ib qho tshwm sim hu ua nplua nplej ntxiv dag zog.
Mechanism
Lub hauv paus ntsiab lus lies nyob rau hauv lub blocking nyhuv ntawm grain ciam teb nyob rau hauv dislocation slip. Rau polycrystalline, dislocation txav yuav tsum kov yeej qhov kev tawm tsam ntawm cov ciam teb, qhov no yog vim qhov kev taw qhia ntawm cov dislocations ntawm ob sab ntawm cov nplej ciam teb sib txawv, yog li nyob rau hauv ib lub nplej, plam dislocations tsis tuaj yeem ncaj qha hla tus ciam teb rau hauv cov nplej. cov nplej uas nyob sib ze, tsuas yog nyob rau hauv cov qoob loo ciam teb nrog ntau qhov kev cuam tshuam los ntawm qhov kev xav tau ntawm kev ntxhov siab, txhawm rau txhawm rau txhawb kev txav ntawm dislocations nyob rau hauv cov nplej uas nyob ib sab tau tsim tawm. Yog li qhov zoo dua cov nplej, qhov siab dua lub zog ntawm cov khoom.
Txoj cai
Qhov zoo dua cov nplej, qhov loj dua ntawm thaj tsam ntawm thaj tsam, raws li Hall - Nplooj ntawv daim duab, qhov me dua qhov nruab nrab txoj kab uas hla ntawm cov nplej d, lub zog ntau dua ntawm cov khoom σs
Cov txheej txheem ntawm grain refinement
①Crystallization txheej txheem tuaj yeem nce los ntawm kev nce qib ntawm subcooling, kev kho metamorphic, kev co thiab nplawm kom nce tus nqi ntawm nucleation los ua kom cov nplej;
② rau qhov txias deformation ntawm cov hlau tuaj yeem tswj tau los ntawm qib ntawm deformation, annealing kub los kho cov nplej;
③ tuaj yeem ua tau zoo, annealed cua sov txoj kev kho kom zoo dua cov nplej;
④ tuaj yeem muab ntxiv rau cov hlau alloying ntsiab lus, tsim cov theem tshiab los tiv thaiv kev loj hlob ntawm cov nplej.
Qhov thib ob theem ntxiv dag zog
Txhais
Nyob rau hauv cov hlau matrix muaj lwm ib los yog ob peb lwm theem, muaj cov theem no los txhim kho lub zog ntawm cov hlau. Vim muaj cov txheej txheem sib txawv kom tau txais theem thib ob, theem thib ob ntxiv dag zog yog muab faib ua: ① Precipitation Strengthening: tau txais theem thib ob los ntawm theem hloov kho cua sov ② Dispersive Strengthening: tau txais theem thib ob los ntawm hmoov sintering lossis oxidation sab hauv.
Mechanism
Dislocations ntsib theem thib ob thaum lawv txav mus los thiab yuav tsum tau hla lossis txiav los ntawm theem thib ob, yog li theem thib ob cuam tshuam qhov kev txav ntawm cov dislocations, uas ua rau muaj zog ntawm cov khoom.
Piv txwv
Lub xub ntiag ntawm carburizers hauv steel ua rau muaj zog ntawm cov hlau.
