EFFECT OF STRAIN RATE ON MICROSTRUCTURE EVOLUTION AND MECHANICAL BEHAVIOR OF A LOW C HIGH Mn TRIP/TWIP STEELS

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1 u 48 8 u 5 & Vol.48 No ν 5 K u ν ACTA METALLURGICA SINICA May 2012 pp e&od/. C 9 Mn TRIP/TWIP 7rnb&= l d Ca_V,g ± Π x Ξwv ( [ -h? fi I, d ) (x 'C>@ Ξ6XBΩ, ' ) ±/f Fe 18Mn r C 3 Mn TRIP/TWIP /R*ffffiuν s 1 ] w Wffkkfff. Rff+ρK_*ffffiuν5 ( s 1 ), *ffffiuff3 Mn TRIP/TWIP / k=k3λ8e k*,»fl*ffffiuk G, =K3ΛWΦ_u ffr; R~ρK_*ffffiuν5 ( s 1 ), *ffffi uff3 Mn TRIP/TWIP /kφ_u8e k*, =K3ΛWΦ_u»fl*ffffiuk G W ; R*ffffiu s 1 j, 3 Mn TRIP/TWIP /=K3ΛAYf 957 MPa, Φ_uYf 55.8%, 57 Sk Y] w ;»fl*ffffiukfl3, y ψ ffdξy, xeffrefl8ße Z. 02 SEM, TEM W XRD oß ffffr._kffkψufffij, Rν7*ffffiuν 5 kk_ffrpay 8ef±yψe yψ ffwrffx%, "6R*ffffiu s 1 k3ffik_pay8e9h@gk *, ohoψrf. :>+ TRIP/TWIP /, *ffffiu, ffkfiff, yψ ff, rffx% ps36b< TG X[(MH A Xm%< (2012) EFFECT OF STRAIN RATE ON MICROSTRUCTURE EVOLUTION AND MECHANICAL BEHAVIOR OF A LOW C HIGH Mn TRIP/TWIP STEELS WU Zhiqiang, TANG Zhengyou, LI Huaying School of Materials and Metallurgy, Northeastern University, Shenyang ZHANG Haidong MCC Capital Engineering & Research Incorporation Limited, Beijing Correspondent: TANG Zhengyou, lecturer, Tel: (024) , tangzy@smm.neu.edu.cn Supported by National Natural Science Foundation of China (No ) and Fundamental Research Funds for the Central Universities (No.N ) Manuscript received , in revised form ABSTRACT The microstructure and mechanical properties of Fe 18Mn low carbon high manganese TRIP/TWIP steels during tensile tests in the range of initial strain rate of s 1 at room temperature were studied. The inverse effect of strain rate on strength of steel was produced, the strength and ductility of steels decreased with increasing strain rate in the range of quasi static tensile strain rate of s 1. While inverse effect of strain rate on ductility of steels was produced in the range of dynamic tensile strain rate of s 1, the strength and ductility of materials increased significantly with increasing strain rate. The tensile strength of high manganese TRIP/TWIP steels was 957 MPa and their elongation was 55.8%. These results indicated that Fe 18Mn steel had excellent mechanical properties and good fracture resistance. The higher the strain rates applied, the less martensite, the more directions of deformation twins. The microstructure evolution of the specimen was analyzed by SEM, TEM and XRD, martensitic transformation and * M~ E@ oflbff vy N fflλ fi5l' : , fz+5l' : ψ_λß : Gr3, ffi, 1987 οe, %te DOI: /SP.J

2 594 ff u 48 8 deformation twins were produced during the tensile deformation, and adiabatic temperature rise effect made the matrix softening during the high speed deformation. KEY WORDS TRIP/TWIP steel, strain rate, microstructure evolution, martensitic transformation, deformation twin s C 4 Mn TRIP/TWIP 0wρ pq-<μ D30, 68 4l4ΞXΨ`v, )z TRIP (transformation induced plasticity) l+=8y<ffi40l 4Ξ, TWIP (twinning induced plasticity) l+8y ffi40l x [1], p)b+3<-<<bp,φlvu, ffizgπ} ffi4ξaxpfil. Sn}f9QB z, <b,φ>sqblfisfflvs s 1 i, ρωfl&ufz-<μdφlfisfflvs 10 3 s 1 ffi 9 [2]. L<fi-<χΨΞAxl?r, 4+fifflvQ4 Mn TRIP/TWIP 0lx w^ zο?rldχ. awgfi/9o, N}Xfi4 Mn TRIP/TWIP 0l 0ffi3}<@χ2Π >χ filpfifi,ffx l.a, fi4+fifflvql]kx 0 Z [3], S ff PXfi,ff P#ΦQlfisv98 ]l:χ,!us /jfisl3,x (paxx4mlhn$l+p, fi fffisv9 0l(νSρ BΞX.ag/j>χ Ψx lffi4. +fifflvfis C 4 Mn TRIP/TWIP 0^ v9x xicl.a, m KNgßS-<μD Φzlf9Xp3ΞAx [4]. οffi 0+fifflvfis C 4 Mn TRIP/TWIP 0filflfiX^ x l.a=6 8n}#$X+3 n. "ßN Grassel p [5] X Curtze p [6] 0g((+ fifflvfi TWIP 0^ x l.a, a#=2fisqb zfilflfifi TWIP 0sfiqUl.a!v 0. Sahu p [7] Hwang p [8] X Parka p [9] 0g Al Refi TWIP 0S4+fifflvQfilflfil.a, 4+fifflv fi TWIP 0^ v9l.av Z w. fi<+fifflv, (( `fi)ο6eχμ($](. ρωbffi!vpqe χ [10] : fi,ff+fifflvο6ρ< s 1 i, +fifflv]< 10 1 s 1 9 ff+fifflvο6. μb»z?rgn}f9x-<χψz-<μdφlfisfflv, 0gs C 4 Mn TRIP/TWIP 0Sfi,ffL`+fiffl vο6 ( s 1 ) X ffl`+fi fflvο6 ( s 1 ) l AL`nfflQBzfilfl fixfisv9wqu. 9»ZY3 TRIP/TWIP Cfl + nus C 4 Mn TRIP/TWIP 0filx levw 4gffiAff4. 91Slpρ_4ΞAx }e8l-< 3HΞ0fflf9ffiAU pn. 1 Lc42 Fe 18Mn kg cdz"-+q!vma, ) g >χ (weχπ, %)9: Mn 18.10, Si 3.15, Al 3.12, C 0.03, S 0.009, P 0.008, Fe >e. ΩΞz±U> 30 mm ^l±ψ, F` Is 1150 ffla 2h,IY>^Ξ9 3mmlff/, Q*Q 1100 ffla 30 min `SYs^ Ξ9 1 mm. fl`ωsyff Is 1000 ffla 10 min HNPU`ΦU. Y3[56ΦIPU`l0ffv>P- 1 οsll`~. +fifflvο s 1 ll`nffls MTS /jnfflqx!v, +fiffl vο s 1 ll`nffls Zwick HTM fflL`/jnfflqX!v, L`ρf@Yvρf](. &Q[56ΩL`/`l~ v>nfflχkο3~. &Q SSX 550 V x- (SEM)!v SEM χk. 3 foφfi X [[Ω[ (XRD) ~ ffi±!vhl, F`Ω ~ ffus5 50 ml l 30%H 2 O 2 X 5mLl HF l! ΦkZNßz!vffi±#l, 13 D/Max Ra X [[Ω [fld H]fi>. ΩL`/`l~ v>m.9 3mm lfsffi!, ^Ξ9 50 μm, 3 TenuPol 5 qxν fl Πffifl!vΠffi, xνß3 9% (!rχπ) l4s 1) Nß, xξ V, AΞ9 20, 13 TECNAI G [x- (TEM) L6L`/`l4Lfil. Fig.1 T 1 K_} FW Dimension of tensile specimen (unit: mm) 2 Lc?;k5Y 2.1 AJ'^`W - 2 w Fe 18Mn 0fi,ffX ffl`l@b+^ +fi<[. Bffi<L, S+fifflvο s 1 +fi<[vs](lfig9v, Fe 18Mn 0Stil+fiο6 Zg=(, F`!Q xfis» ; S xfis», +^ +filx] X. c+fifflv s 1 k, S xfisjq», +fi lx, +^Xhgρ n`8]$ξlqfi, F`QX h; S `l xfis», +^ +filx]8$ps l*', *'l$ξ(w ], #7aρ» D~g ;», ms~ Φl. ffi 1 w Fe 18Mn 0S((+fifflv L`kl^ x. SffizBffi<L, ffitsfflv s 1 Xt4fflv 10 3 s 1!vL`fisk, Fe 18Mn 0 ffiulbtl^ x, (χ684l>l4ξ, Ψ`vμ 4. )z, Fe 18Mn 0S+fifflv9 1.67

3 u 5 & Fq2n : )ρfltωq C 2 Mn TRIP/TWIP.ρjffρV t7j-` s 1 k, >L4ΞZg 915 MPa, Ψ`v9 55%, 4 rzg MPa %. S+fifflv s 1 k, >L4Ξ9 957 MPa, Ψ`v9 56%, 4 rzg MPa %. B, ff PXfi, ff P# Φ Qlfisv98 ]l:χ, Sfi,ffL`+fifflv s 1 k, Fe 18Mn 0l>L4 ΞXΨ`v ffi+fifflvl H fis; S ffl` +fifflvο s 1 k, ffi+fifflvl H, Fe 18Mn 0l>L4ΞXΨ`v X. 5ffi 1 hbffi<l, Sο 0l+fifflvο6, ^ x S+fifflv s 1 kluiw. - 3 w+fifflv , X 10 3 s 1 kl c+^x+fi0gv c+filfig<[. S- 3a Bffi <L, 29+fifflvQ~ lc+^ c+fi<[lfig 9v]t](, Sbxfis:, c+^ c+fi<[]} Z, ffi+filx, Szb](c+fiQ=(. S s fflvl`kc+^4, +fi0gug=9φt. ffic+ fielx, 29+fifflvQl+fi0gvLUΦT7%, +fifflv s 1 k+fi0gv!nφt4< +fifflv s 1 l+fi0gv. 2 +fifflv Ql+fi0gv LUSQfi, QXhfl`;Qfilfig QB, Fe 18Mn 0S+fifflv s 1»ν+fi fflv s 1 QLU!nl+fie»] 0.05 ffi 9. ffiφs xfis» l+fi0gv!nluj2, J.E/jiC, )Ψ`vμJ], οffi sfflvl`k 8=]lΨ`v, =Tl x. S- 3b Bffi<L, S+fifflv s 1 kfisl Fe 18Mn 0lc+^X+fi0gv c+filfigkn. 5R-Bffi<L, Fe 18Mn c+filx, + fi0gvxc+^xhgρ n`8]$ξlqfi, F `Xh, 8$Psl*', #7 Fe 18Mn 0Sc+fi X l», +fi0gv8*nll U, affiφs4fflfisqbz8sgug. Fe 18Mn 0S fffis#φql:iahffiwfi l T 2 Fig.2 Fe 18Mn /R''*ffffiuPk?A*] *ff;z Engineering strain stress curves at strain rates in the range of s 1 (a) and the range of s 1 (b) for the Fe 18Mn steel ) 1 Fe 18Mn 1T)),fl wrm_λy» Table 1 Ultimate tensile strength (σ b ), ultimate elongation (δ) and product of strength and ductility of Fe 18Mn steel at different strain rates Strain rate, s 1 σ b,mpa δ, % σ b δ, MPa % T 3 Fe 18Mn /R''*ffffiuPffrkkb*]W*ff/ fffiu»b*ffkfffjm Fig.3 True stress and strain hardening rate against true strain curves of Fe 18 Mn steel at strain rates of and s 1 (a), and 10 3 s 1 (b)

4 596 ff u 48 8 filflfi8k. 2.2 ZUso Fe 18Mn 0S((+fifflvL`/`l XRD %. Bffi<L, Fe 18Mn 0fis/`lfil5 γ fcc ] ε hcp ]X α bcc ]fi>, )z α bcc ]9 α % fi!m α }z!. ν fis/`ω[!»u, Fe 18Mn 0L`fis` 111 γ, 200 γ, 220 γ X 311 γ l γ fcc ]l Ω[!ΦTΠT; 110 α, 200 α X 211 α l α bcc ]Ω[!ΦTX4; 002 ε l ε hcp ]Ω[!fig i. ffiφ, SL`fisQBz»fg TRIP l hbffi< L, S+fifflv s 1 k γ fcc ]lω[! s<)ß+fifflvklω[!, R+fifflvk Fe 18Mn 0l α }z!φfie4<)ß+fifflvklφfie. 13m ν μ e g Fe 18Mn 0S((+ fifflvl`/`l:]l!rχπ, Pffi 2 οs. Bffi< L, L`fis`, z! (γ) l!rχπφtπz, α } z!φtxffi, ε }z!z8πzafig(], ffiφl` QBB»fg γ α, γ ε, ε α m γ ε α lφfi. 5ffi 2 hbffi<l, +fifflvfi α }z!φfi e.a ], ffi+fifflvl H, α }z!φfie!9vwfisl, ffl`k α }z!φfiez<fi, ffl`klφfie. - 5 w Fe 18Mn 0S((+fifflvL`fis/` l SEM d. - 5a wipu`=fisl Fe 18Mn 0l T4fil, /l`lfil8ßο#ml/ly&lu. ) z, ΠQ@l]9 z! (γ),,*dω]9%fi! (α F ). μz XRD χk, Fe 18Mn 0fis/lfil»8 z!p! %fi!x ε }z!fi>; fis`lfil9 z! %fi! ε }z!x α }z!; fis/`%fi! s 8»fΦTfig. S- 5a hbffi<l, &Q 1000 HNPU 30 min ΦU`, Fe 18Mn 0l]ffiΠ z!p! VS]e/ ly&, Zep! 8/ly&. )z],χ/ly& Fig.4 T 4 Fe 18Mn /K_._k XRD $ XRD patterns of Fe 18Mn steel before and after tensile deformation *q<&[ßο, o<&[lnρßο, #7 fcc &N y&±9111&±ο, ρ9 z!p! ly& 8ρ l?f, ßΞi l?fffi9 60 m 120, ρ9&[ 2ρ9yfN*. SL`fis`ly& (- 5b f) B ffi»u, Fe 18Mn 0filz8]elsfiy&, ffiφl` QB»fgsfi:»yf, y TWIP l+. Fe 18Mn 0 lsfiy&ρ,χ5/ly&s+^l!3q9f, h8 ρ,χse/ly&l&[ s>. - 5b 9+fifflv s 1 kl`fis`lt4fil. Bffi<L, ) sfiy&ffiffi`9yfn*vs, μ8zeffi9yfn* lsfiy&vs, #7],χsfiy& o<&[lnρ ßο. +fifflv s 1 (- 5c) X 10 1 s 1 (- 5d) kl`fis`lt4filzlu ffic9ρflyf N*, +fifflv s 1 (- 5e) X 10 3 s 1 (- 5f) kl `fis`lt4filz]ffivsffi9ρflyfn*] cfl6, sfiy&hlu1<, #7S4fflL`QBz, s fiy&stπlk N(wN, ],χ o<&[,. amugψφ, ffi+fifflvl H, ffi9((ρf lyfn*+, fi&[!vg!ρ+χ6, Ogg&[. - 6 w Fe 18Mn HNPU 30 min Φ U` (fis/) l TEM d. S- 6a X b Bffi<L, Fe 18Mn 0HNPU`VS&ο#ml/ly&X]e 5X, <4/ly&s>ο ~ν e#φ: y&οlο ± H]<ρΩ>f]ffiΞ&οlο±, οffi/ly& &:S fcc z!filws>. Fe 18Mn 0l5X s, LU]e5X. ]e5xl9f9`~fisk+fi: e}z!lsuφfiffiwsfiy&l9f, ffia8yl# Φ [11,12]. &QΩ[Ψ4, Fe 18Mn 0HNPU`8 ε }z! (- 6c) X bcc %fi! (- 6d), #7%fi! 8Ze>Xχ*. ε }z!llu8y<+fi:» α }z!l9f, S5X sl4 Mn 0z»U [13], }z! ws ε }z! GPfiχwc! ε ]flοplu, Ψffl5XUfi*QE 5xc#fiX5fiwweyg, y B5 ε }z!φfi9 α }z!. y fcc z! (γ) * Q hcp z ] (ε) i`φfi9 bcc }z! (α ). - 7 Tsg Fe 18Mn 0+fifflv X 10 3 s 1 kl`fis`l TEM d. S-Bffi<L, α }z!s z!&οxsu;] (- 7a), (ks&[ ) 2 Fe 18Mn 1)),fl wma0a;^"sψ± Table 2 Volume fraction of the constituent phases measured by XRD (volume fraction, %) Strain rate, s 1 ε α F α γ

5 5 N GNSM : ONHVNO C O Mn TRIP/TWIP P PQNQW IJPRK B RL Æ j B _ 5 Fe 18Mn SEM Fig.5 SEM images of the Fe 18Mn steel before deformation (a) and after tensile deformation with strain rates of s 1 (b), s 1 (c), 101 s 1 (d), 102 s 1 (e) and 103 s 1 (f) j 6 Fe 18Mn TEM SAED Fig.6 TEM images of the Fe 18Mn steel before tensile deformation (a) annealing twins and stacking faults (b) large amounts of stacking faults (c) image and corresponding SAEDP of ε martensite (εm ) (d) image and corresponding SAEDP of αf 597

6 598 B RL Æ 48 7 Fe 18Mn TEM Fig.7 TEM images of Fe 18Mn steel after tensile deformation with strain rates of s 1 (a e) and 103 s 1 (f, g) (a) martensite presented at grain boundary (b) intragranular martensite (c) ε martensite (d) single twin system (e) primary and secondary twin systems (f) dislocation and slip in twin system (g) intersection of several sets of deformation twins 8 Z 7 α ]Y. % (; 7b), ]Y.&a_ e5r K., a_ ik )7!!]Y. e, bf Mc f b #:+), "$e +&4l j2. ; 7c lkek,,' ε ]Y., MAV, & = & &$, g1) [Y. &']Y., ]'0 γ α, γ ε, ε α \ γ ε α &. V8 T : T W &! ' s 1 I, &à$_v`'2` ' (; 7d), 5R&^`àL 7G& &à (; 7e). &! ' 103 s 1 I, [Y.abL(/`'.h bf#mc (; 7f) #ÆVA< &à+b'@ / S (; 7g). "X, &! )`' ]#'.-*. E &!,Y, `'[ni, G_ `'2`<ÆV Æ

7 u 5 & Fq2n : )ρfltωq C 2 Mn TRIP/TWIP.ρjffρV t7j-` 599 ρflyfn*φfi, a@ SEM L6lμO]&. 3 5YQG 3.1 f'pe0f'i1 α INRq'-h] +fifflvfis C 4 Mn TRIP/TWIP 0^ v9 l.a, S ]BΞXffO<+fifflvfi+fi:» α } z!φfil.a. +fi:» α }z!φfi@i^» Φfilfl]:χS<, +fi:» α }z!φfi(as xfiszf>suw, h 50 +^!9qn> ^& GI^ > ^(νl,χ. fisaξj "}z!i^»φfilfl4aξ M s, ο lqn> ^Ji; J "+fi:»}z!φfilfl4aξ M d, ο lqn> ^J], 4< M d Ω(Q8}z!Φfi. S],zfi Fe 18Mn 0!v4+fifflvl ffl`, Ω^N@s+ fifflvlfi,fffis((li^ Dχ, fi,ff#φql Isfil+fi+fi:» α }z!φfil.a i, ) xfisqbbffi<χwρ9paqb, ff#φqbk 9wρ9:Imfi:IQB, ]νfi,ffl`, 5<S ff4ffll`qbzl3,xx(pax, +fi 9flI S Πlk ( A,JUg],z, S et3,a Ξh4 [14]. :IAh ΔT B5Qr [15] : ΔT = ΔQ = β ε2 σdε (1) ρc p ρc p ε 1 rz, ΔQ 9qn fi lφfie, ρ 9/jΠΞ, C p 9νIO, β 9qn ΦfiI lnπ, σ 9c+^, ε 9 c+fi. fi<+fifflv s 1 fisl4 Mn 0, β ρω? 0.95, ρ=7.8 g/cm 3, C p =0.46 kj/(kg K), qn &Qn4l σ ε <[rχig. &Qr (1) B L Fe 18Mn 0S+fifflv s 1 k,δt =121. fi s/`8pr ]la7, οωjfifilflfix^ v9 9f.a. Fe 18Mn 0»5 z!x%fi!d>, z!5 X XC xl]ifi Fe 18Mn 0filflfiX^ v 99f}».a, fisaξxg >χw.a z!c xx5x fl}»l&fi [16,17]. S5X sl Fe 18Mn 0 ( A5X 9 15 mj/m 2 ) filz5x ffi, >X]fi Z (- 6b). "(l]k 0 [9] Ts, AΞX +fifflvfi α }z!φfil.a, &am&fiet5 X»ffig, 5XRBWflwlE ffk=y<f α }z!&7φfi. s+fifflv#φq, Jq» P0^ XhfflΞ, }z!φfifflξ i, Φfie Z, aw ffi +filx, qn> ^X4, }z!]fil> ^X, 7 8Il+, }z!φfifflξx, ΦfieXffi. S 4+fifflv#ΦQ, c+fiezgρ ni`, 4+fiffl v#φ:iah ], z!5x μh4, fisaξz gm " M d Φfi, α }z!]fii^ > ^Πi, ο lqn> ^Sfisz ffx, az(g]fi> ^, α }z!φfifflξπ, ΦfieΠZ. οffi Fe 18Mn 0 S ffl`ql α }z!φfie;i<sfi,ffl` QlΦfie (ffi 2), #7Sfi,ffL`#ΦQ, ffi+fi fflvlfis, }z!φfiex. 0 [18,19] hφ, z! 0+fi0gvXhG <)zl}z!φfi, 7}z! ΦfifflvJH, ΦfieJffi, +fi0gvxhμjh. ο ffi+fifflv s 1 Ql+fi0gvXhν+fi fflv s 1 H (- 3a), +fi0gloφt. 3.2 f'pe0jfk'^-h] +fifflvfi Fe 18Mn 0y&s Xχ* 68}».a, ypffi il+fifflv X s 1!vL`, Fe 18Mn 0~ SfisQBzμ j9f]elsfiy& (- 5b X 5c), #7sfiy&] ffi o<&[lnρßο. ffi+fifflvl H, sfiy &fii= OitΠ, #7y&χ*9<;M, 5<fis k Π, sfiy&ffi o<&[,. +fifflvhbffi4 m.a Fe 18Mn 0lyfΨr, c+fifflv sk, ( ρ&[ y&ρfffi9(ρρf, p8zesfiy&]fl. ffi+fifflvl H, `~s>lsfiy&@ss>ls fiy&]cflx, (ρ&[ 8cfimffifisfiy&]fl >ρ ffiξ, LUffi9sfiy&]cfl6lUg (- 7f X g), #7 fiy&c]#v. +fifflvfiyffis9f}».a,»w5<c xfiszgρ nk, 5< 4 l+^uz, sfiy& 6fl ffiρ Πel>X, S4 l+fifflvq, >XN(wfi, sfiy& 6l+^Ω X], S T!gyffisl»f [20]. 3.3 f'pe0 Fe 18Mn 8'^`W-h] +fifflvο s 1 kfi Fe 18Mn 0^ v9l.aχ9c9,χ. vρ,χw+fi fflv s 1 lfi,ffl`k, ffi+fifflvl Hh4et xicxψ`vfis. y& 9flΛ±n ε +fifflvji, ε c Ji. #7+fifflv ik/jsfik ;, +fi:» α }z!xsfiy&8νelk f;, et/j4 xx [21]. Fe 18Mn 0Stil+fifflv s 1 k α }z!lφfiez 40%, 4<)ß+fifflvlΦfi e. Fe 18Mn 0SfisJ(, %fi! Sfis, ]e>x S%fi!&[ Ψr, 9f8Yl+fi0g, rql+fi ffiag z!+fi:»]fil^ > ^. c+firq gφfi#φk, z! fiscq ΨΦfi9}z!, ρ ρ±5<c`l!r((, ``l!r ], 9fgffi, ßΛgdfi±dfi,! '*>XΠΞlx7X, et g4l+fi0g ^; nρρ±, }z!μb0ξ 4, fi >XlN "8ßΛ!3, pi0l+fi0g ^;DS 4Φ#. v,χw+fifflv s 1 ffl`k,

8 600 ff u fifflvfi4 Mn TRIP/TWIP 0lΨ`v9fμl +,»ffiu9 ffi+fifflvlh4/j>l4ξxψ` vffi4. ffl`k, Fe 18Mn 0;Mfis» l α } z!φfiez<fi,ffl`klφfie, a>l4ξcx. 5R<L.a+^l&fi(pw}z!lΦfie, y ffisμw.a Fe 18Mn 04gqvX4glOl}» &fi. Syf9»fisΨrlfisz, yf+^ ffi+ fifflvlffi4 fis [22], #7SdfifyfΦglQB z, +fi0gbξlffi4w5<dfi±xy&l.a, (wyfο +^l.a [23]. ff4ffll`k, z!& VSl]effi9ρflyfN*]cfl6, ρρ±bffi,fi&!ω,χl>f, pien(y<dfil>ffii 8Y<dfi [12] ; z!&[»ffi9ρfly&!ρ+o g, S psfi=;m, X x; nρρ±, ffi9ρf9 flsfiy&φeq&[χ>=il:b, S X g/ j!ρ+fislß^, U>+fi0gvl!ρ+ffi4. n 0, ffisfil!v, sfiy&ωffiλp!56> ffii F, >X5<»μΠ N Iffl; n0, y&οlvsμß Λg>XlN, pi Fe 18Mn 0»f xfisk C (=]lß^, 5<VSac ß^, &R Fe 18Mn 0 l4ξjd~x. S ffl`fis#φq, Fe 18Mn 0l+fi0gv Xc+^ c+filfig?u$psl*', aw+fi 0gXp!Sg]c!3lμO. ffl`fisqbz l+fi0g»@ffiq 3 9ρ±8K: (1)4ffl fffis ψvg>xlfldfixffindfi, pi/jx70g; (2) 8]el z!]fi9}z!, }z!l0gl+iffit U; (3) +^l(φh4, z!p!»]effi9ρf] cfl6lsfiy&χ6, &[igog, (k]elsfi y&ο8ltßλg>xdfi. fffisqbzlp! Sg»w&9:IAhl+pi/jSg, >X!<d fi [14,24], (k:iahpi5x h4, ψvgfisq Bz z!f}z!l]fi [16,17,25]. 4?G (1) Fe 18Mn 0Sfi,ffL`#ΦQ, ffi+fiffl vl H, Fe 18Mn 0l>L4ΞXΨ`v fis. S ffl`#φq, Fe 18Mn 0l>L4ΞXΨ`v +fifflvlh4 X]. Fe 18Mn 0S ffxfi,ffl `` ffl`` VS]effi9ρflyfN*]cfl6. (2) ffl`k;mfis» l α }z!φfiez <fi,ffl`klφfie, a>l4ξcx, yffis μw.a Fe 18Mn 04gqvX4glOl}»&fi. (3) S ffl`#φq, Fe 18Mn 0l+fi0gv Xc+^ c+filfig?u$psl*', aw+fi 0gXp!Sg]c!3lμO. *@X[ [1] Zhang W N, Liu Z Y, Wang G D. Acta Metall Sin, 2010; 46: 1230 ([:fl, pda, 3M. fl, 2010; 46: 1230) [2] MasaakiI,KozoK.Int J Impact Eng, 2000; 24: 117 [3] Liu C Y, Li D Z, Wei Y H, Hou L F, Liu D F, Jin X Z. J Iron Steel Res, 2010; 22(6): 48 (pql, V ],?(i, ]X", p}#, flv^. /$±/, 2010; 22(6): 48) [4] Liu W, Li Z B, Wang X, Zou H, Wang L X. Acta Metall Sin, 2009; 45: 285 (p <, Vrψ, 3 _, μ ", 3Zo. fl, 2009; 45: 285) [5] Grassel O, Kruger L, Frommeyer G, Meyer L W. Int J Plast, 2000; 16: 1391 [6] Curtze S, Kuokkala V T. Acta Mater, 2010; 58: 5129 [7] Sahu P, Curtze S, Das A, Mahato B, Kuokkalab V T, Chowdhurya S G. Scr Mater, 2010; 25: 6 [8] HwangSW,JiJH,ParkKT.Mater Sci Eng, 2011; A528: 7267 [9] ParkaKT,HwangSW,JiJH,LeeCS.Proc Eng, 2011; 10: 1002 [10] Hsu C H, Lee S C, Wang L, Dong X. Mater Chem Phys, 2002; 73: 174 [11] Murr L E, Staudhammer K P, Hecker S S. Metall Trans, 1982; 13: 627 [12] Yu Y N. Fundamentals of Materials Science. Beijing: High Education Press, 2006: 559 (=1ρ..i@ om. (: 3offlCKfi], 2006: 559) [13] Xu Z, Zhao L C. Metal Solid Phase Transformation Principle. Beijing: Science Press, 2004: 86 (}, ]`=. fl Gρ ffdt. Kfi], 2004: 86) [14] WuCC,WangSH,ChenCY,YangJR,ChiuPK,Fang J. Scr Mater, 2007; 56: 717 [15] Lee W S, Xiea G L, Lin C F. Mater Sci Eng, 2001; A257: 256 [16] Hokka M, Kuokkala V T, Curtze S, Vuoristo T, Apostol M. JPhysIVFr, 2006; 134: 1301 [17] Huang B X, Wang X D, Rong Y H, Wang L, Jin L. Mater Sci Eng, 2006; A : 306 [18] DeAK,SpeerJG,MurdockDC,MatayaMC,Comstock RJ.Metall Mater Trans, 2006; 37A: 1875 [19] Schramm R E, Reed R P. Metall Trans, 1975; 6: 1345 [20] Bolling G F, Richman R H. Acta Metall, 1965; 13: 709 [21] Zhou X F, Fu R Y, Su Y, Li L. J Mater Therm Treat, 2009; 30(5): 145. (~hfl, %J#, ff #, V $..ihot, 2009; 30(5): 145) [22] Bohle J, Chmelic F. J Alloys Compd, 2004; 378: 207 [23] Barnett M R, Keshavara Z, Beer A G, Atwell D. Acta Mater, 2004; 52: 5093 [24] Xue Q, Liao X Z, Zhu Y T, Gray III G T. Mater Sci Eng, 2005; A : 252 [25] Allain S, Chateau J P, Bouaziz O, Migot S, Guelton N. Mater Sci Eng, 2004; A : 158 (Λ}uy: t~z)