تأثیر چگالی نابجایی‌ها بر رفتار تغییر شکل فولاد بینیتی فوق مستحکم

نویسنده

گروه مهندسی مواد، دانشگاه شهید مدنی آذربایجان، تبریز

چکیده

وجود فریت بینیتی و آستنیت پرکربن پایدار در دمای محیط با ابعاد نانومتری در ریزساختار فولادهای بینیتی فوق مستحکم،سبب دست‌یابی به مجموعه‌ای از خواص استحکامی و انعطافی منحصر به فرد در این دسته از فولادهای نانوساختار شده است. در این پژوهش تأثیر تغییر چگالی نابجایی‌ها در حین آزمایش کشش در دمای محیط، بر رفتار تغییر شکل فولادهای بینیتی نانوساختار دما پایین مورد بررسی قرار گرفته است. نتایج نشان می‌دهند جذب نابجایی‌های تیغه‌های فریت بینیتی توسط آستنیت موجود در اطراف آن‌ها، باعث کاهش کارسختی و در نتیجه افزایش قابلیت فرم پذیری فریت بینیتی در حین تغییر شکل و در نهایت دست‌یابی به ترکیب مناسبی از استحکام و انعطاف‌پذیری می‌شود.

کلیدواژه‌ها


عنوان مقاله [English]

Effect of Dislocation Density on Deformation Behavior of Super Strong Bainitic Steel

نویسنده [English]

  • B. Avishan
چکیده [English]

Presence of nanoscale bainitic ferrites and high carbon retained austenites that are stable at ambient temperature within the microstructures of super strong bainitic steels makes it possible to achieve exceptional strengths and ductility properties in these groups of nanostructured steels. This article aims to study the effect of the dislocation density variations during tensile testing in ambient temperature on deformation behavior of nanostructured low temperature bainitic steels. Results indicate that dislocation absorption from bainitic ferrite subunits by surrounding retained austenite reduces the work hardening and therefore increases the formability of bainitic ferrite during deformation, which in turn results in a suitable combination of strength and ductility.

کلیدواژه‌ها [English]

  • Nanostructured bainite
  • Strength
  • Ductility
  • Dislocation
  • Work hardening
1. Khare, S., Lee, K., and Bhadeshia, H.K.D.H., “Carbide-Free Bainite: Compromise between Rate of Transformation and Properties”, Metallurgical and Materials Transactions A, Vol. 41, pp. 922-928, 2010.
2. Caballero, F.G., Santofimia, M.J., García-Mateo, C., Chao, J., and De Andrés, C.G., “Theoretical Design and Advanced Microstructure in Super High Strength Steels”, Materials & Design, Vol. 30, pp. 2077-2083, 2009.
3. Garcia-Mateo, C., Caballero, F.G., and Bhadeshia, H.K.D.H, “Low Temperature Bainite”, Journal de Physique IV, Vol. 112, pp. 285-288, 2003.
4. Caballero, F. G., Bhadeshia, H.K.D.H, Mawella, K.J.A., Jones, D.G., and Brown, P., “Very Strong Low Temperature Bainite”, Materials Science and Technology, Vol. 18, pp. 279-284, 2002.
5. Caballero, F.G., and Bhadeshia, H.K.D.H., “Very Strong Bainite”, Current Opinion in Solid State and Materials Science, Vol. 8, pp. 251-257, 2004.
6. Yoozbashi, M.N., and Yazdani, S., “Mechanical Properties of Nanostructured, Low Temperature Bainitic Steel Designed Using a Thermodynamic Model”, Materials Science and Engineering: A,
Vol. 527, pp. 3200-3205, 2010.
7. Bhadeshia, H.K.D.H., “Properties of Fine-Grained Steels Generated by Displacive Transformation”, Materials Science and Engineering: A, Vol. 481,
pp. 36-39, 2008.
8. Bhadeshia, H.K.D.H., “New Bainitic Steels by Design”, Modelling and Simulation for Materials Design, Vol. 76, pp. 227-232, 1998.
9. Bhadeshia, H.K.D.H., Bainite in Steels, 2nd edn, London, Institute of Materials, 2001.
10. Caballero, F.G., Garcia-Mateo, C., Santofimia, M., Miller, M., and García de Andrés, C., “New Experimental Evidence on the Incomplete Transformation Phenomenon in Steel”, Acta Materialia, Vol. 57, pp. 8-17, 2009.
11. Bhadeshia, H.K.D.H., and Edmonds, D., “The Mechanism of Bainite Formation in Steels”, Acta Metallurgica, Vol. 28, pp. 1265-1273, 1980
12. Bhadeshia, H.K.D.J., and Christian, J., “Bainite in Steels”, Metallurgical Transactions A, Vol. 21, pp. 767-797, 1990.
13. Caballero, F. G., Miller, M., Garcia-Mateo, C., and Cornide, J., “New Experimental Evidence of the Diffusionless Transformation Nature of Bainite”, Journal of Alloys and Compounds, Vol. 577, pp. 626- 630, 2013.
14. Bhadeshia, H.K.D.H., “The Bainite Transformation: Unresolved Issues”, Materials Science and Engineering: A, Vol. 273, pp. 58-66, 1999.
15. Chatterjee, S., Wang, H.S., Yang, J.R., and Bhadeshia, H.K.D.H., “Mechanical stabilisation of austenite”, Materials Science and Technology,
Vol. 22, pp. 641-644, 2006.
16. B. Avishan, S., Yazdani, F., Caballero, T , Wang, C., and Garcia-Mateo, “Characterisation of Microstructure and Mechanical Properties in Two Different Nanostructured Bainitic Steels”, Materials Science and Technology, Vol. 31, pp. 1508-1520, 2015.
17. Avishan, B., Garcia-Mateo, C., Morales-Rivas, L., Yazdani, S., and Caballero, F.G., “Strengthening and Mechanical Stability Mechanisms in Nanostructured Bainite”, Journal of Materials Science, Vol. 68,
pp. 6121- 6132, 2013.
18. Bhadeshia H.K.D.H.,: Materials Algorithms Project, https://WWW.msm.cam.ac.uk/map/steel/programs/ mucg83.html
19. Chang, L.C., and Bhadeshia, H.K.D.H., “Austenite Films in Bainitic Microstructures”, Materials Science and Technology, Vol. 11, pp. 874-881, 1995.
20. Cullity, B.D., and Stock, S.R., Elements of X-Ray diffraction, Prentice Hall, New York, 2001.
21. Williamson, G.K., and Hall. W.H., “X-ray Line Broadening From Filed Aluminium and Wolfram”, Acta Metallurgica, Vol. 1, pp. 22-31, 1953.
22. Williamson, G.K., and Smallman, R.E., “III. Dislocation Densities in Some Annealed and Cold-Worked Metals from Measurements on the X-Ray Debye-Scherrer spectrum”, Philosophical Magazine., Vol. 1, pp. 34-46, 1956.
23. Singh, S.B., and Bhadeshia, H.K.D.H., “Estimation of Bainite Plate-Thickness in Low-Alloy Steels”, Materials Science and Engineering: A, Vol. 245, pp. 72-79, 1998.
24. Cornide, J., Garcia-Mateo, C., Capdevila, C., and Caballero, F.G., “An Assessment of the Contributing Factors to the Nanoscale Structural Refinement of Advanced Bainitic Steels”, Journal of Alloys and Compounds, Vol. 577, pp. 43- 47, 2013.
25. Caballero, F.G., Yen, H.W., Miller, M.K., Yang, J.R., Cornide, J., and Garcia-Mateo, C., “Complementary Use of Transmission Electron Microscopy and Atom Probe Tomography for the Examination of Plastic Accommodation in Nanocrystalline Bainitic Steels”, Acta Materialia, Vol. 59, pp. 6117-6123, 2011
26. Caballero, F.G., Miller, M.K., Babu, S.S., and García-Mateo, C., “Atomic Scale Observations of Bainite Transformation in a High Carbon High Silicon Steel”, Acta Materialia, Vol. 55, pp. 381-390, 2007.
27. Bhadeshia, H.K.D.H. and Honeycombe, R.W.K., Steel, Microstructure and properties, Butterworths-Heinemann (Elsevier), Amsterdam 2006.
28. Zhang, K., Zhang, M., Guo, Z., Chen, N., and Rong, Y., “A New Effect of Retained Austenite on Ductility Enhancement in High-strength Quenching–Partitioning Tempering Martensitic Steel”, Materials Science and Engineering: A, Vol. 528, pp. 8486-8491, 2011.
29. Wang, Y., Zhang, K., Guo, Z., Chen, N., and Rong, Y., “A New Effect of Retained Austenite on Ductility Enhancement in High Strength Bainitic Steel”, Materials Science and Engineering: A, Vol. 552,
pp. 288- 294, 2012.
30. Zhang, M.X., and Kelly, P.M., “Crystallography of Carbide-Free Bainite in a Hard Bainitic Steel”, Materials Science and Engineering: A, Vol. 438,
pp. 272-275, 2006.

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