Termal Kararlılığı Arttırılmış Demir Esaslı Ferritik Çelik Tozlarının Sıcak Pres ve Sıcak Ekstrüzyon (ECAE) Yöntemleri ile Konsolidasyonu

Year 2016, Volume 31, Issue 1, 0 - 0, 23.03.2016

Hasan KOTAN

https://doi.org/10.17341/gummfd.17389

Abstract

Bilyeli değirmenler ile üretilen yüksek mukavemetli tozların konsolidasyonunda temel hedef mekanik özelliklerinde önemli bir kayıp olmadan bu tozların birleştirilerek porozite içermeyen ürüne dönüştürülebilmesidir. Son yıllarda yapılan araştırmalar sıcak ekstrüzyon ile yüksek kayma ve basınca maruz bırakılan tozların porozite içermeden, teorik yoğunluklarında birleştirilebileceğini göstermiştir. Bu çalışmada sıcak presleme ve yüksek sıcaklıklarda çok geçişli ekstrüzyon (ECAE - equal channel angular extrusion) teknikleri kullanılarak nanokristalin Fe-Ni-Zr tozlarından konsolide edilmiş ferritik alaşımların üretimi araştırılmıştır. Elde edilen sonuçlar sıcak presleme metodu ile teorik yoğunluğa ulaşılamadığını, ancak sıcak ekstrüzyon yöntemi ile yapısında porozite içermeyen ve teorik yoğunlukta malzeme üretilebileceğini göstermiştir. Konsolidasyon sonucunda mikroyapıda tane büyümesi gözlenmesine rağmen üretilen bu çeliklerin sertliği (5-6 GPa) günümüzde kullanılan yüksek mukavemetli çeliklerin üzerindedir.

Keywords

Toz metalurjisi, Mekanik alaşımlama, Tane büyümesi, Mekanik özellikler, Ekstrüzyon, ECAE

References

• Youssef K. M., Scattergood R.O, Murty K.L., Horton J.A., and Koch C.C., “Ultrahigh strength and high ductility of bulk nanocrystalline copper”, Applied Physics Letters, Cilt 87, 91904-91907, 2005.
• Zhao Y.H., Liao X.Z., Cheng S., Ma E. and Zhu Y.T., “Simultaneously increasing the ductility and strength of nanostructured alloys”, Advanced Materials, Cilt 18, 2280-2283, 2006
• Hall E.O., “Variation of hardness of metals with grain size”, Nature, Cilt 173, 948-949, 1954
• Meyers M. A., Mishra A., and Benson D. J., “Mechanical properties of nanocrystalline materials”, Progress in Materials Science, Cilt 51, 427-556, 2006
• Koch C.C., and Weertman J., “Bulk nanostructured materials” , Noyes Publications, 393, 2002
• Kumar K. S., Van Swygenhoven H., and Suresh S., “Mechanical behavior of nanocrystalline metals and aloys”, Acta Materialia, Cilt 51, 5743-5774, 2003
• Million B., Ruzickova J., Velisek J., and Vrestal J., “Diffusion processes in the Fe-Ni system”, Materials Science and Engineering, Cilt 50, 43-52, 1981
• Koch C.C., “The synthesis and structure of nanocrystalline materials produced by mechanical attrition: A review”, Nanostructured Materials, Cilt 2, 109-129, 1993
• Koch C.C, “Synthesis of nanostructured materials by mechanical milling: problems and opportunities”, Nanostructured Materials, Cilt 9, 13-22, 1997
• Soni P.R., "Mechanical Alloying, fundamentals and applications", Cambridge International Science Publishing, 2001
• Koch C.C, Ovid'ko I.A., Seal S., and Veprek S., “Structural nanocrystalline materials”, Cambridge, New Yok, 25-85, 2007
• Suryanarayana C., "Mechanical alloying and milling", CRS Press Taylor and Francis, 2004
• Kirchheim R., “Reducing grain boundary, dislocation line and vacancy formation energies by solute segregation. I. Theoretical background”, Acta Materialia, Cilt 55 5129-5138, 2007
• Kirchheim R., “Reducing grain boundary, dislocation line and vacancy formation energies by solute segregation: II. Experimental evidence and consequences”, Acta Materialia, Cilt 51, 5139-5148, 2007
• Millett P.C., Selvan R.P., Bansal S., “Stabilizing nanocrystalline materials with dopants”, Acta Materialia, Cilt 53, 2329-2336, 2007
• Weissmuller J., “Alloy effects in nanostructures”, Nanostructured Materials, Cilt 3, 261-272, 1993
• Darling K.A., VanLeeuwen B.K., Koch C.C., and Scattergood R.O., “Thermal stability of nanocrystalline Fe–Zr alloys”, Materials Science and Engineering A, Cilt 527, 3572-3580, 2010
• Darling K.A., VanLeeuwen B.K., Semones J.E., Koch C.C., Scattergood R.O., Kecskes L.J., and Mathaudhu S.N., “Stabilized nanocrystalline iron-based alloys: Guiding efforts in alloy selection”, Materials Science and Engineering A, Cilt 528, 4365-4371, 2011
• VanLeeuwen B.K., Darling K.A., Koch C.C., Scattergood R.O., and Butler B.G., “Thermal stability of nanocrystalline Pd81Zr19”, Acta Materialia, Cilt 58, 4292-4297, 2010
• Saber M., Kotan H., Koch C.C., Scattergood R.O., “Thermal stability of nanocrystalline Fe–Cr alloys with Zr additions”, Materials Science and Engineering A, Cilt 556, 664-670, 2012
• Kotan H., Darling K.A., Saber M., Koch C.C., Scattergood R.O., “Effect of zirconium on grain growth and mechanical properties of a ball-milled nanocrystalline FeNi alloy”, Journal of Alloys and Compounds, Cilt 551, 621-629, 2013
• Kotan H., Darling K.A., Saber M., Scattergood R.O., Koch C.C., “Thermal stability and mechanical properties of nanocrystalline Fe–Ni–Zr alloys prepared by mechanical alloying”, Journal of Materials Science, Cilt 48, 8402-8411, 2013
• Guduru R.K., Darling K.A., Kishore R., Scattergood R.O., Koch C.C., Murty K.L., “Evaluation of mechanical properties using shear–punch testing”, Materials Science and Engineering A, Cilt 395, 307-314, 2005
• Jian L.i., Malis T., Dionne S., “Recent advances in FIB–TEM specimen preparation techniques”, Materials Characterization, Cilt 57, 64–70, 2006
• Chowdhury S.G., Xu C., Langdon T.G., “Texture evolution in an aluminum alloy processed by ECAP with concurrent precipitate fragmentation”, Materials Science and Engineering A, Cilt 473, 219–225, 2008
• Kotan H. , Saber M., Koch C.C., Scattergood R.O., “Effect of annealing on microstructure, grain growth, and hardness of nanocrystalline Fe–Ni alloys prepared by mechanical alloying”, Materials Science and Engineering A, Cilt 552, 310–315, 2012
• Karaman I., Haouaoui H., Maier H.J., “Nanoparticle consolidation using equal channel angular extrusion at room temperature”, Journal of Materials Science, Cilt 42, 1561-1576, 2007
• Grosdidier T., Goran D., Ji G., LIorca N., “On the processing of hetero-nanostructured metals for improved strength/ductility balance by ECAE and SPS techniques”, Journal of Alloys and Compounds, Cilt 504, 456-459, 2010
• Youssef K.M., Scattergood R.O., Murty K.L., Koch C.C., “Nanocrystalline Al-Mg alloy with ultrahigh strength and good ductility”, Scripta Materialia, Cilt 54, 241-256, 2006
• Koch, C.C., “Optimization of strength and ductility in nanocrystalline and ultrafine grained metals”, Scripta Materialia, Cilt 49, 657-662, 2003