48 12 Ö Vol.48 No ACTA METALLURGICA SINICA Dec pp Î µ TG142.1, Á A Ì µ (2012)

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1 8 12 Ö Vol.8 No ACTA METALLURGICA SINICA Dec. 212 pp Ë É Ï¼ºÇ¹ Cr13 Ä ²¾ ÅÂ 1,2) 2) 2) 2) 3) 1) È ½, È 693 2) ÉÛÕÛ ½ÕÛ, 181 3) Ò ÄÚ Õ, Ï³ 616 ÖÜ» Cr13 Ü Ö ÊÐÀ 2 ÙÝÊ Ð (ECAP) ¼ Ð Ô. Ö Ö µ ÖÔÀ¼É, Ð ECAP Ð Í 6 7, Ð ½, 1% 3%(Ö Ì) «Ë¼ ±Ö. Đ ¼É, ± Ë¼ ± ß Î, Ò ± ß ¾ µm 18 2 nm. ¹ Â Ý¼É, ECAP Ð Í +7 Ð, ÝÊ ¹ÇØ ( 7 ) (212 J/cm 2 ), «¼³ Ç Ì «Á µ Ó µ ( ¾ÒÌ 1%, 3% 7%). «¼ ÒÌ Ð Ð ÒÌ. ±» Cr13 Ü Ö Ê, ÙÝÊ Ð (ECAP), Ô, ¹, Î µ TG12.1, Á A Ì µ (212) MICROSTRUCTURES AND MECHANICAL PROPERTIES OF Cr13 FERRITIC STAINLESS STEEL PROCESSED BY EQUAL CHANNEL ANGULAR PRESSING AND SUBSEQUENT ANNEALING TREATMENT YANG Muxin 1,2), YANG Gang 2), LIU Zhengdong 2), Du Xiqian 2), HUANG Chongxiang 3) 1) Faculty of Material Science and Engineering, Kunming University of Science and Technology, Kunming 693 2) Institute for Structural Materials, Central Iron and Steel Research Institute, Beijing 181 3) College of Architecture and Environment, Sichuan University, Chengdu 616 Correspondent: YANG Gang, professor, Tel: (1) , yanggang@nercast.com, HUANG Chongxiang, professor, Tel: (28)86919, chxhuang@scu.edu.cn Supported by National Natural Science Foundation of China (Nos.971 and ) and Fundamental Research Funds for the Central Universities (No.212SCUA) Manuscript received , in revised form ABSTRACT In comparison with austenitic stainless steel, the ferritic stainless steel has obvious advantage in price due to its lower nickel content. However, the relatively poor ductility and toughness limit its applications. To overcome these shortcomings, a new thermo mechanical approach, involving processing by severe plastic deformation and proper annealing treatment to introduce a bimodal grain size distribution, was adopted for achieving high work hardening capability, superior strength ductility combination and good impact toughness in metallic materials. In this work, the combined effects of severe plastic deformation and partially recrystallization on the microstructures and mechanical properties of a ferritic stainless steel were investigated and compared with the traditional forging and annealing process. An solution treated ferritic stainless steel (Cr13, AISI ) was subjected to equal channel angular pressing (ECAP, an important kind of severe plastic deformation) * Û ± Í 971, ßÌÄ±± Ö ² 212SCUA Ù ÄÆ Î : , ÄÆ ÆÎ : Ç : Ð,, 1982 ½, ½ DOI: 1.372/SP.J

2 12 Ö : ØÜÉ» «Cr13 Û Õ É Ó ³ 123 for two passes at room temperature and subsequent annealing treatments. Optical microscope (OM) and transmission electron microscopy (TEM) observations showed that ultrafine-grained (UFG) structure was obtained in the ECAP processed sample. After subsequent annealing at 6 7 for 1 h, partial recrystallization occurred and the remaining island like UFG grains (1% 3% volume fraction) distributed uniformly. Statistical measurements indicated that the microstructures of the annealed ECAP samples exhibited a bimodal grain size distribution including relatively coarse recrystallized grains (CRGs) and remaining ultrafine grains (UFGs). The average grain size for CRGs determined from OM observations was µm and the average grain size for UFGs measured from TEM observations was 18 2 nm. By contrast, the annealed forged sample (7 ) exhibited a unimodal grain size distribution with average grain size of about 7 µm. Tensile and impact tests showed that the strength of Cr13 ferritic stainless steel could be improved greatly through grain refinement by ECAP process, and the strength ductility combination could be modulated via sacrificing some strength for ductility by subsequent annealing treatment. In comparison with the conventional sample (forging+annealing at 7 ), the tested steel processed by the optimal processing involving ECAP deformation and annealing treatment at 7 showed higher yield strength, uniform ductility and static toughness (enhanced by 1%, 3% and 7% respectively), simultaneously a comparable impact toughness (212 J/cm 2 ). The refined microstructure and higher work hardening capacity were responsible for the improved mechanical properties of the annealed ECAP samples and the strengthening mechanisms were discussed based on the experimental results. KEY WORDS Cr13 ferritic stainless steel, equal channel angular pressing (ECAP), microstructure, tensile properties, impact toughness Cr13(AISI ) Ë» C Đ¹ Ì.8%, Cr Đ¹ 12% 1% Ý Ë, Ö ËÛ½Đ ³Ã Û Ë ß ½ [1]. Đ Å¹ Ð, Cr13 Ë Ð ¾ßÈ Ý Ý + ¹Â Ï [1,2]. Ñ Ì Ë, Cr13 Ý Ëº ¹ Cr-Ni Ì Ë, Ê ±, Ø Ì ¾ÌÂ ¼ÅËÑ [1,2]. ½ Ç Ó Ú ¾ ( ² >1 µm [3] ) Ò Ð [3,]. Wen [] Ý½Ê, Â + Ý Ï Ë (1Cr13 Ë) Ý ² ½ Ê ÓÍØ º. Song [,6] Calcagnotto [7] Ý½Ê, Ë ÜÞ ¹ Ø Ý ²½ ØÈ., ¾ Cr13 Ý Ë Ø, Ø Æ Ý, Í ¾ ²Ê [2], ÈÙ½ ( TMCP [3] ) Ø ², ÆÝ Ó ² ½ µm ¾ [1,3]. Ý [8,9] ½Ê, ÚÞË Ñ (ECAP) Ì½ ( ² 1 µm 1 nm ) ¾ Å. É Cr13 Ë ½ Ó ¼., Ò Ý Ë ECAP Ý. Ð, Ý ² ½ Ò Å Ç Cr13 Ë ² Ý. ºÓ ¹, ECAP ¾ Ð ¹Î ( ¹¹ßÈ 1 [8] ), Ø½. Yang [1] ß ECAP Ñ Ú 6 mm Õ Fe ÃĐ ± Ó ² 3 nm Ý. ÉÑÌ½ Fe ÂÐ Ú Ý, ¼ ºÊ Ú Fe 1/2 [1] Á Ñ Ø Ç, Ú ĐÑ. [11 13], ÔÒ ¹Î ¾ ÍÆ, µ ¾È, ¹Î µ., Wang [12] Ma [13], Õ Ñ ¾» Ñ, Å Ì½ (<3 nm) Ï ² (bimodal structure). ÉÑÏ ²½ Ð ¹ µ, ÍÐ Í [12]. ÎÞ, Å Ñ Ô Ò ¹Î ¾ Ô [1 16]. ² ¾Ð Cr13 Ý ËÑ ECAP ¹ Î½ Ñ µ Ü¹ Õ Ð Ï» Ã ½Ì, º¹ ĐÑ Ï¾, Ñ ½ Ñ ¾ Cr13 Ý Ë Ï À, ÓÍÝ Ë µ É Ê. 1 È Þ ¾ Ú 16 mm ¹, ( ¹ Í, %) : C.1, Cr 13.12, Si.36, Mn.11, S.12, P.13, Fe ¹. Ï Ù ± Ï Ê 11 mm ¾, Ñ 11 Å 1 h Ð Ñ ECAP Þ. Þ ECAP Ë Ú 16 mm, Ë 3, Ë 9. Á ¾¾Ð ¾ Æ B C Ú [1], Þ Ø Ñ Æ¾ Ù ÑÔÆ Ð Þ 9 Ï¾ Ø Ñ, 2 Ø ECAP Ñ ( Å ¹¹ 2) [17]., Æ Ñ ĐÑ 6, 6, 7 7 Å¾ Ñ 1 h. ¾, ¾¹ ĐÑ Ð± Ñ. Á º Ã ÜÄ HS WDW Ì«ºÃÞ

3 12 È 8 ± Ï, ¹ 2. 1 /s. ºĐÑ»» Ú 3mm, Ê1mm. ºĐÑ Đ Ù Å. Á Ã ± JBN 3B Ì ÃÞ ± Ï. ÃĐÆ GB/T , mm 1 mm mm Charpy V Ì ÃĐ, Đ Ù Å. ECAP Ñ ÃĐ V Ì Ô ¾, Å ±. (OM) ÕÁ Olympus GX1 Ï. ÃĐÃ : CuCl 2 (1 g)+fecl 3 (3. g)+ Á (2. ml)+ Ó ( ml)+ Þ ( ml) + ( ml). (TEM) ÕÁ Hitachi 8 Ì TEM ±Å, Ñ 17 kv. TEM ĐÑ 2 2 ÅÚÂ¾ Ï Ñ, %( Í) Í Þ. ÕÁÇ Ñ¾Å Ü ÔÇ. 2 È½ 2.1 ÆÃ Cr13 Ý Ë Ñ ßÈ Ñ [1,2,18]. [1] Å 6 83 Å. 1a ¹ ĐÑÑ 6 7 Å Ñ Þ Á º µ ¹Å., ¹ ĐÑ ÂÐ (YS) Æ Ð (UTS) 78 MPa; ºÊ (UE) ¼ ºÊ (TE).7% 13.%. Ñ Ñ, ¹ ĐÑ Ð ¾È, ÓÍ. Ø, YS ÕÃ² 6 Å ĐÑ 379 MPa ¾È 7 Å ĐÑ 19 MPa;, UE ÕÃ² 7.% ± 28.%. ¾, 1a,b Ð ĐÑ ºÆÅ., Ð ĐÑ YS, UTS, UE TE : 19 3 MPa, 2.8% 37.%. ²Ö À, ¾ Ð ĐÑ, ¹ 7 Å ĐÑ ³Í Ð (YS=2 MPa, UTS=37 MPa), ½ Å (UE=2.%, TE=37.%).» ¹ ĐÑ, ¹ 7 Å ĐÑ Ð Ì. 1b Ñ ĐÑÑ 6 7 Å Ñ Þ Á º µ ¹Å. ² À, Ñ ECAP ¹Î, ĐÑ YS UTS Đ MPa, ÌÐ ĐÑ (19 3 MPa) ÓÍ , Ì¹ ĐÑ ( 78 MPa) ÓÍ 8% 63%, Ø UE 1.3% Æµ. Ñ Ñ ĐÑ º ¾Ê ¹. ÓÍ, Ð ¾È, Ã, 7 Å ½., ¾ 1a, b, 6 7 Å Ð, Ñ ĐÑÐ Í ¹ ĐÑ. Ì, Ñ 7 Å ĐÑ YS UTS 22 MPa, ¹ 7 Å Engineering stress, MPa Normalized work-hardening rate S E S E+A6 S E+A Engineering strain, % S E S S F+A7 S S E+A7 (b) SE+A7 S E+A True stress, MPa = 1 S F S S F+A7 S E+A True strain, % 1 Ð Cr13 Ê ¼ Ñ º Fig.1 Tensile engineering stress strain curves of the Cr13 S F S E (c) = 1 steel processed by forging and annealing treatments (a) and ECAP and annealing treatments (b), and normalized work hardening rates Θ against the true strain (c) (Yield strength and uniform elongation are distinguished by open circles and squares in Fig.1a, b, respectively. The inset in Fig.1c shows the curves of Θ against true stress. S F means original forging sample; S means solid solution sample; S E means ECAP processed sample; S F+A6, S F+A6, S F+A7 and S F+A7 means forging+annealing at 6, 6, 7 and 7 samples, respectively; S E+A6, S E+A6, S E+A7 and S E+A7 means ECAP+annealing at 6, 6, 7 and 7 samples, respectively)

4 12 Ö : ØÜÉ» «Cr13 Û Õ É Ó ³ 12 ĐÑ (2 37 MPa) Í 1% 1%; Ð, UE TE Đ 27.% 2.8%, Ì¹ 7 Å ĐÑ (2.% 37.%) ÓÍ 3% 3%. ±Ë Þ½Ê, ECAP ÑÑ Cr13 Ë ÀÐ, Ñ ß Ð [1] ¾ ÞË Ð Ï Å, ÐĐ Ì Ð. 1c ¹ ECAP Ñ ĐÑ 7 Å Þ Ú ¹ Θ Ê ¹ ( Ê µ) ¹ Å ¾. Ì, ÐÆÐ ĐÑ Θ ¹. Considère Đ Å¾ ¾ º [11,19], ¾ : ( S e ) ė = S (1) Θ = 1 S ( S e ) ė (2), e Ê ¹, S Ê µ, ė ¹. ² (1, 2), Å Θ 1, ÒÄ¾, º Î». Θ Õ± ¾Ð µ, Õ± ¾ µ, Ð Đ ¾ [19]. Ù 1c, º µåæâ Ð ĐÑ, ß ¹ ECAP ÆĐÑ ¹, ĐÑ Θ e Å Ê ¹ e ¾ ¾È, Ø Ñ ĐÑ Θ Ã È. É½Ê ¹, ¹ Ñ ĐÑ º µê ¾È, ¾ ¹Ð, Û ÒÓ Ä¾. 7 Å, ¹ Ñ ĐÑ Θ Ê Ç, Ð ¹ ( µ) Ó¾ Ñ 7 Å ĐÑ ¹ µìð. É½Ê, ĐÑ µ Ð, ÓÍ, Ø Ñ 7 Å ĐÑ Θ ÓÍ Ø. 2a ¹ Ñ ĐÑÑ Ñ Ô µ Å. Ôµ U Ô º¼ Þ, ¾ Å ¹Î ¼ µ, [2] : U = εf σdε (3), σ ¹ µ, ε f ¼ ¹. 2a, ¹ ĐÑ Ôµ ¹ Å Í ±Ñ Ñ ĐÑ ¾. Ö, Å ¹ Ð, ¹ ĐÑ U Í, Ñ ĐÑ U Á, 7 ÅÑ, Đ 19. MJ/m 3 ( ¹ 7 Å ĐÑ Ôµ (11.2 MJ/m 3 ) Í 7%). Ôµ ¾Ð [21]. ²Ö, º¹ Static toughness, MJ/m 3 Impact toughness, J/cm (a) (b) ECAP-processed Original forging Annealing temperature, o C Annealing temperature, o C 2 µ½ Ð Cr13 ÊÓ µ Fig.2 Effect of annealing temperature on static toughness (a) and impact toughness (b) of the Cr13 steel after forging and ECAP deformation and annealed at different temperatures, respectively ĐÑ, Ñ ĐÑ. Ð ECAP Ñ Al-Cu Ý, [21] Ó ºØÔµ Ò, ÓÍ, Ð, ÓÍ Ôµ. 2b ¹ Ñ ĐÑÑ 6 7 Å ¹. 7 Å ¾, ¹ Ñ ĐÑ ÓÍ Í; 7 Å ±, ĐÑ ¹ Ó ³ Á, Í Đ 212 J/cm 2. Û, Ñ ĐÑÑ 7 Å, Ð Ð, ÌÍ. ±, ECAP Ñ¹Î +7 Å Ñ Æ Cr13 Ý Ë ± Ð µ. 2.2 ³ Í 3a ¹ ĐÑ Å., ¹ ĐÑ Ì ², ²ÎÐ Ù, Ã, Ó, Ó ² 131 µm. 3b Ð ĐÑ. ² À, Ð ĐÑ Ì Ô, ² µ¹đ Ã, Ó

5 ` P \, o h&b 9 µm. 3c i7mh m b? [. 7mh mih&u - V < G $ pn R, h& \=L2 -V- ; Yh&$ Y"8Y<G% V - 1B } 1 ( #I f ); h m-v * *h\, = B h [ ` }, b ) - pn [ 8 it V* Z. ( #I f ). a f -h mm 7 = B [h [. H, [hh&u > h B :, [ p 126 C 7 g f 8 }, h ) U, K3 87 M. b d B3 i ECAP 7m m 6, 7 7 m b? [. & H, 7mh ma 6 VY 8b78 M [hh&, b b *UqK F. 2 b d e ;qi1r, 7m mi B=(=B 72 [h ECAP -V&s. QN-V & s $ 7 [hh& W Y \v98b 7 8 M } 1, fæ < B : * m\ =. b ig R a> Z 3 Cr13 Fig.3 OM images of Cr13 steel in the different states (White arrows in Fig.3c mark the fiber like areas subdivided by deformation bands within the elongated grains, while the black arrows mark contorted grain boundaries) (a) original forged (b) solid solution (c) ECAP processed C,g 6lg R Z a>lj Cr13 Fig. OM images of the different Cr13 samples (Inset in the lower left corner of Fig.b is the magnified image of the square area in Fig.b, in which the island like ultrafine grained areas indicated by arrows are surrounded by recrystallized grains) (a) forging+annealing (7 (c) ECAP+annealing (7 ) ) (b) ECAP+annealing (6 (d) ECAP+annealing (7 ) )

6 12 Ö : ØÜÉ» «Cr13 Û Õ É Ó ³ 127 Ã Ð¹Î² ½ ( Á ). ² À, ºØÓ º ², Ð¹Î ½ Ì Î, Ê Î, ½ÊÅ ½ ¹ ÌÍ, ½. Í, ÉÆ Ð¹Î ÍÕÃ¾È. ½Ê, 6 Å, 7 Å 7 Å ĐÑ Ð¹Î Í 3%, 2% 1%. a Cr13 ËÑ ECAP Ñ Ì TEM ¾ Û Õ. Ù, ¹¹ ( 2) Ñ ĐÑ Æ Í, Ø Î ÍÆ Ã ß, Æ ² Ï Ò Å ( 371 nm) Ê. ¾ Û Õ Ê Ê Ð, ½Ê Â. a µ¾ë Á Ê, Æ ¹Ã,, Ã µ²íæ Ã ( ß). Ö, Î Ð Æº, Î Ä, Æ ÌÍ µ¹ôò, Đ Ë, a Á. b d Ñ ĐÑ 6 7 Å Ü TEM Å. Å µ, Ð¹Î nm Ì½. b d, Ì G» Å ², Ø Ì½. Ñ ECAP+6 Å Ñ ( b), ĐÑ Æ ¾È, Ì Æ º Ð ½, Î ±º Þ Â, Í ÊÚÐ. ² ¾ Î Þ¹ µ, Õ Ü¹ Ò, Ø ÍÒ ÌÅ Û Ú, ½ÊÉ Ò ÅÕÃ Ë Þ ¹. 7 Å ( c), ĐÑ Æ ¾È, Æº ½ ÕÃ Æ Ø ( c Á ). Ö, Ò ÅÈ Ú ÐÌ Ë Ü, Ò ² Ð Ô. 7 Å ( d), Ä À Ê, Ç Ð ( d Á ), ÕÁ Æº ½, ÍÒ Æ Ì ; Ò Î ÂÌ, Ê, Ò ÅÚ ( d Á ), ½Ê ÍÒ Þ¹ ÅÆ ± Ð Cr13 Ê Ý Ë TEM Ä ÚµÔ Fig. Typical TEM images of different Cr13 samples (Insets are the corresponding select area electrom diffraction patterns. Recrystallized grains are labeled by G. The white arrow in Fig.a indicates an area with high dislocation density, while the black arrow indicates a dislocation cell block. The black arrows in Fig.c indicate grains with low dislocation density. The black arrows in Fig.d indicate extinction contours of subgrain boundaries, while the white arrow indicates grain with low dislocation density) (a) ECAP processed (b) ECAP+annealing (6 ) (c) ECAP+annealing (7 ) (d) ECAP+annealing (7 )

7 128 È 8 ² [22]. ĐÑ Û Õ( Ú 2 µm, b d ), Û Å À ßÞ, Í ÕÃ. É½Ê, ĐÑ Þ µ¹, µ¹ Í ÕÃ Ã. Éº TEM ÊÆ ¾ÕÁ Æ Í Ã., Í, ÐÛ ÕÃ¹, ¾È, ½Ê ±, Ò Õ ÃÊ, ²ÍÎ¾È. ¹ ÕÁ½Ê, ECAP Ñ¹Î +6 7 Å ĐÑ Þ 2 Ñ ², b d ÕÁ ¾Ú Å ² b d TEM ÕÁ Ò Å Ì½ ². 2 Ñ ² 6a. ² Ì ½ ² Ï [23], 3 Â TEM Å ¾ 3 ² Ï. ² 6a À, Þ Ñ ĐÑ Þ Ï Ì½, Ó ² 371 nm. Ñ, ĐÑ ² Ì½ ² Ï, 2 Ñ ² Â 1 Í¹, ² Ï ÐÌ. Ù 6a, ÓÍ, ² Ó ².1 µm 8.3 µm; Ì½ ² ¹ ¾ÌÃ, 6, 7 7 Å, ØÓ 18, 38 2 nm. 6b ¹ ĐÑÑ 7 Å Þ ². ² À, Þ ² Ï, µm. Æ 6a, b Ï¾, À, ¹ 7 Å ĐÑ Ó ² Ñ 7 Å ĐÑ ²Ó 1 Í¹, Ì ½ ²Ó 2 Í¹. É½Ê, º¹ ĐÑ, Ñ ĐÑ ²Ê ½. 3 ÀÊ Ù TEM ÕÁ Þ, ECAP Ñ Cr13 Ë Õ Ü¹ Ç Ð Ì. Æ ÔÒ ¹Î². ECAP ¹Î ¹ Õ ¹ Ó ¼ Î (ÓÍÎ ), Ð ¼ ² [3], È ¼ Î, Û Î ½ Ã ² ( ). ØØ Ð¹Î ½ µ Ò Þ¹ ½ Ü¹ Ì½ ². Ù b d, ECAP ĐÑ Ð¹Î Ù, Í µ± ¼ ¾Â Ò, Ã µ Ò, Ë Þ¹, ÐÛ ÕÃÞ¹ Ò ½ÊÏ ± ² [22,2]. Ð¹Î ½ Æ Ì½ Î, ĐÑ Æ È Ð ¼ÌÍÆ Í, Ñ ĐÑ ¾Í Ð. Frequency, % Frequency, % d UFG =.18 m d UFG =.38 m d UFG =.2 m d UFG =.371 m d CRG =.1 m d CRG = 7.7 m d CRG = 8.3 m (a) ECAP-processed ECAP+annealing (6 o C) ECAP+annealing (7 o C) ECAP+annealing (7 o C) Grain size, m (b) Oringinal forging d = 131 m 2 16 Forging+annealing (7 o C) 12 d = 7 m Grain size, m 6 Ð Cr13 Ê Ý ± ß Fig.6 Grain size distributions of the ECAP processed Cr13 steel before and after annealing at 6 7 for 1 h (a) and grain size distributions of the forged Cr13 steel before and after annealing at 7 for 1 h (b) (The relatively coarse recrystallized grains (CRG, >1 µm in size) and ultrafine grains (UFG, <1 µm) were measured by OM and TEM observations, respectively) Æ ECAP Ñ ¹ ĐÑ Þ Ð ½ ¹ Ï¾, Ð Ñ ¹ Ñ 7 Å ¹ 7 Å ĐÑ Ôµ ºÊ 7., º ¹ Ð ĐÑ, Ñ ĐÑ ºÊ ¾È, ÂÐ ÓÍ 3 ( 1b), ØÔµ (

8 12 Ö : ØÜÉ» «Cr13 Û Õ É Ó ³ 129 Static toughness, MJ/m Static toughness Uniform elongation Solidsolution ECAPprocessed Original forging ECAP+ annealing Forging+ annealing Uniform elongation, % 7 Ð Cr13 ÊÐ 7 Ý «½³ Fig.7 Comparisons for static toughness and uniform elongation between the forged and ECAP processed Cr13 samples before and after annealing treatment at 7 µ ) ºÐ ĐÑ Ó. Ì ¹ ĐÑ, ºÊ ¾ÈÊ, ØÐ Ê ( 1 ), ØÔµ Ð ĐÑÃ 39%. ² Þ, º¹ ĐÑ, Ñ ĐÑÐ ØÓÍ Æ Ò ( ) Ê ½ ( 6a). 7 Å, ECAP Ñ ¹ ĐÑ Đ ± µ ( 2a, b). ² 7, Å ¾, Ñ 7 Å ĐÑ Ôµ ¹ 7 Å ĐÑÍ 7%, ÂÐ ºÊ Í 1% 3%, ( 1). À, Ñ 7 Å ĐÑ µ ± Ö ºÊ À. ¾ 1c ½Ê, Ñ 7 Å ĐÑ Ø ¹ µ ( Θ ) ØÓÍ. ¾, Ì½ ¾ ¹ µ Ã Ú ¾, ½ ÞÈ Θ ÈÃ [11]. ² Ì½Ò Ñ ĐÑ Θ Ã Ú ĐÑ ( 1c). Đ Ö, Ñ 7 Å ĐÑ Θ ÓÍÖ Ñ ²¾ ¹ µ., Ñ ĐÑ Ð¹Î Î Æ ÔÌ½ ² ( b d) ¾ ¹ µ ÓÍ [13,19,2]. ¾» Ñ ĐÑ Ü¹ ½Ê, Ü¹ºĐÑ µ (Ôµ ) ¹ Æ Ò ( 2a, b),, Ð [1,21]. ² Þ, Ñ 7 Å ĐÑ Ì Ð, Ôµ ÌÍ (Đ 19. MJ/m 3, 2a), ÌÍ (212 J/cm 2, 2b). Å º¹ ²² Å. Õ Ç, º¹ ² ½ Í, ECAP Ï ² ÐĐ½ Í ¾ Ç. (1) ½ : ²½ Ò ½ Î Ã [13], Ä¾ Å. (2) Ë : ¹ Ë ÅÇ¹ À Ú [26], ÓÍ ÀÆµ, ¾ Å. (3) µð Ç¹: Ï µì Ð ¹Î ß µ Ð ² ; Ô Ñ µð ¾, Ç ¹Î ¹Î [12], Û Ä¾²Ð º Þ¹ [13]. ½ (1) Cr13 Ý ËÑ 2 Ø ECAP Ñ¹Î 6 7 Å, ¾, 1% 3%( Í) ÐÌ½ ². ½Ê, ĐÑ ² Ì½ ² µm 18 2 nm, º¹ 7 Å (Ó ² 7 µm), Ê ½. (2) ECAP ÑÑ Cr13 Ý Ë À Ð, Å Ñ ÓÍØ ¹ µ, ½ Ð ÅÞ, ÌÍ µ. Ñ ± ECAP ¹Î +7 Å ÆÑ, Cr13 Ë ÂÐ Ôµ Đ 22 MPa, 27% 19. MJ/m 3, ¹ 7 Å (2 MPa, 2% 11.2 MJ/m 3 ) Í 1% 3% 7%, Ð ÌÍ (212 J/cm 2 ). Á [1] Fujita T. Translated by Ding W H, Zhang X J, Chen Y Z. Heat Treatment of Stainless Steels. Beijing: China Machine Press, 1983: 16 (ÑÙ,, Á Ç, Í¼. Ê Ð. : ³È, 1983: 16) [2] Lu S Y, Zhang T K, Kang X F, Yang C Q, Wang X. Stainless Steel. Beijing: Atomic Energy Press, 199: 77 (, ÁÞ«, ¹, ÐÉ, ³. Ê. :, 199: 77) [3] Wen Y Q. Ultra Fine Grained Steels Microstructural Refinement Theory and Controlled Technology of Steels. Beijing: Metallurgical Industry Press, 23: 7 (». Ë¼ Ê Ê «¼ ¹ Ê. :, 23: 7) [] Song R, Ponge D, Raabe D, Speer J G, Matlock D K. Mater Sci Eng, 26; A1: 1 [] Wen D C. Mater Trans, 26; 7: 2779 [6] Song R, Ponge D, Raabe D. Acta Mater, 2; 3: 881 [7] Calcagnotto M, Ponge D, Raabe D. Mater Sci Eng, 21; A27: 7832 [8] Valiev R Z, Islamgaliev R K, Alexandrov I V. Prog Mater Sci, 2; : 13 [9] Wu S D, An X H, Han W Z, Qu S, Zhang Z F. Acta Metall Sin, 21; 6: 27 (, Ð,, «¹, ÁÆ. É, 21; 6:

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