Dynamic strain-induced transformation of the low carbon steel Q(235) at 770℃ and 850℃ leads to fine ferrite grains. The microstructure characterization and mechanism of the fine ferrite grain were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD) technique. The results show that strain-induced microstructure is the mixed microstructure of ferrite and pearlite, with cementite randomly distributed on ferrite grain boundaries and the grains interiors. EBSD images of grain boundaries demonstrate that high angle grain boundaries (HAGBs) are dominant in both of the deformation induced microstructures occurring below and above A(e3) , with only a few low angle grain boundaries (LAGBs) existing in the grain interiors. It implies that the dynamic strain-induced transformation (DSIT) happens above and below A(e3) temperature and has the same phase transition mechanisms. The refinement of ferrite is the cooperative effect of DSIT and continuous dynamic recrystallization (CDRX) of ferrite. Besides, DSIT is deemed as an incomplete carbon diffusion phase transition through the analysis of microstructure and the previous simulated results. The strengths of the Q(235) steel with refined ferrite and pearlite structure get doubled than the initial state without treated by DSIT and the residual stress in the refined structure is partly responsible for the ductility loss.
参考文献
| [1] | B.Q. Han;S. Yue .Processing of ultrafine ferrite steels[J].Journal of Materials Processing Technology,2003(1/3):100-104. |
| [2] | R. Ueji;N. Tsuji;Y. Minamino .Ultragrain refinement of plain low carbon steel by cold-rolling and annealing of martensite[J].Acta materialia,2002(16):4177-4189. |
| [3] | N. Tsuji;R. Ueji;Y. Minamino .A new and simple process to obtain nano-structured bulk low-carbon steel with superior mechanical property[J].Scripta materialia,2002(4):305-310. |
| [4] | M. R. Hickson;P. D. Hodgson .Effect of preroll quenching and post-roll quenching on production and properties of ultrafine ferrite in steel[J].Materials Science and Technology: MST: A publication of the Institute of Metals,1999(1):85-90. |
| [5] | M.R. HICKSON;P.J. HURLEY;R.K. GIBBS .The Production of Ultrafine Ferrite in Low-Carbon Steel by Strain-Induced Transformation[J].Metallurgical and Materials Transactions, A. Physical Metallurgy and Materials Science,2002(4):1019-1026. |
| [6] | P. J. Hurley;P. D. Hodgson .Formation of ultra-fine ferrite in hot rolled strip: Potential mechanisms for grain refinement[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,2001(2):206-214. |
| [7] | P.J. HURLEY;B.C. MUDDLE;P.D. HODGSON .Nucleation Sites for Ultrafine Ferrite Produced by Deformation of Austenite During Single-Pass Strip Rolling[J].Metallurgical and Materials Transactions, A. Physical Metallurgy and Materials Science,2001(6):1507-1517. |
| [8] | H. Beladi;G.L. Kelly;A. Shokouhi;P.D. Hodgson .The evolution of ultrafine ferrite formation through dynamic strain-induced transformation[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,2004(1/2):343-352. |
| [9] | H. Beladi;G. L. Kelly;P. D. Hodgson .Ultrafine grained structure formation in steels using dynamic strain induced transformation processing[J].International Materials Reviews,2007(1):14-28. |
| [10] | H.Yada;C.M.Li .Dynamic #gamma# -> #alpha# transformation during hot deformation in iron-nickel-carbon alloys[J].ISIJ International,2000(2):200-206. |
| [11] | G.L. KELLY;H. BELADI;P.D. HODGSON .Ultrafine Grained Ferrite Formed by Interrupted Hot Torsion Deformation of Plain Carbon Steel[J].ISIJ International,2002(12):1585-1590. |
| [12] | S. Gourdet;F. Montheillet .A model of continuous dynamic recrystallization[J].Acta materialia,2003(9):2685-2699. |
| [13] | A. Shokouhi;P. D. Hodgson .Dynamic adjustment of ferrite grains during dynamic strain induced transformation[J].Materials Science and Technology: MST: A publication of the Institute of Metals,2007(10):1233-1242. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%