Santrifüj Döküm Yöntemiyle Üretilen Al-Cu Fonksiyonel Derecelenmiş Malzemelerde Üretim Parametrelerinin Malzemenin Sertliği Üzerine Etkisi

Year 2017, Volume: 20 Issue: 1, 121 - 127, 01.03.2017

Semih Ağca Neşet Akar

Abstract

Bu çalışmada, soğuma hızı (0,27 – 7,38 – 14,23 – 21,56 °C/s), kalıp dönme hızı (160 – 225 – 275 rpm) ve döküm atmosferi (açık atmosfer – vakum atmosferi) parametrelerinin santrifüj döküm yöntemiyle üretilen Al-Cu fonksiyonel derecelendirilmiş malzemelerin (FDM) sertliği üzerine etkisi araştırılmıştır. Yapılan deneysel araştırmalar sonucunda, soğuma hızının artması ile sertlik değerinin arttığı ve diğer parametrelerin etkisinin soğuma hızına bağlı olarak farklılık gösterdiği tespit edilmiştir. Yüksek (7,38 – 14,23 – 21,56 °C/s) soğuma hızlarında üretilen döküm parçaların bütün bölgelerinde, kalıp dönme hızı arttıkça sertlik artmış ve açık atmosferde üretilen numunelerin sertliği vakum atmosferinde üretilenlerden daha yüksek çıkmıştır. Düşük (0,27 °C/s) soğuma hızında ise, kalıp dönme hızı arttıkça sertlik, numunenin dönme merkezine uzak bölgesinde artmış, orta bölgede değişmemiş ve dönme merkezine yakın bölgesinde de azalmıştır. Bununla birlikte, açık atmosferde üretilen numunelerin sertliği merkeze uzak bölgede vakum ortamında üretilenlerden daha düşük, orta bölgede aynı ve merkeze yakın bölgede de daha yüksektir. Bu sonuçlar santrifüj döküm yöntemiyle FDM üretiminde, üretim parametrelerinin birbirleri ve malzemenin sertliği üzerine etkisi olduğunu göstermektedir.

Keywords

FDM, Santrifüj Döküm, Sertlik

Effect of Fabrication Parameters on Hardness of Al-Cu Functionally Graded Materials Manufactured by Centrifugal Casting

Abstract

In this study, the effect of cooling rate (0,27 – 7,38 – 14,23 – 21,56 °C/s), mold rotation speed (160 – 225 – 275 rpm), and casting atmosphere (air – vacuum) on hardness of Al-Cu functionally graded materials (FGMs) were investigated. According to the experimental results, it was found that the hardness value became higher with increasing cooling rate and efficiency of other parameters varied according to cooling rate. The hardness increased with increasing mold rotation speed and hardness values of specimens produced in air atmosphere are higher than that of manufactured in vacuum atmosphere for all parts of specimens produced in high (7,38 – 14,23 – 21,56 °C/s) cooling rates. On the other hand, the specimens produced in low cooling rate (0,27 °C/s) have varying hardness values depending on the location of the cast part. Hardness increased with increasing mold rotation speed in the far part of specimens to the rotation axis. It remained unchanged in middle section and decreased with increasing mold rotation speed in parts close to the rotation axis. Also, hardness values of specimens obtained in air atmosphere are lower in far part, same in middle and higher in rotation axis by comparison with the specimens obtained in vacuum atmosphere. Results showed that all parameters affected each other and the hardness in fabrication of FGMs by centrifugal casting.

Keywords

FGMs, Centrifugal Casting, Hardness

References

• 1. Shiota I. and Miyamoto Y., “Functionally graded materials 1996”, Elsevier Science B. V., Amsterdam, 1-14, (1997).
• 2. Miyamoto Y., Kaysser W. A., Rabin B. H., Kawasaki A. and Ford R. G., “Functionally graded materials design, processing and applications”, Springer Science+Business Media, New York, 1-26, (1999).
• 3. Kieback B., Neubrand A. and Riedel H., “Processing techniques for functionally graded materials”, Materials Science and Engineering A, 362: 81-105, (2003).
• 4. Zhai Y., Liu C., Wang K., Zou M. and Xie Y., “Characteristics of two Al based functionally gradient composites reinforced by primary Si particles and Si/in situ Mg2Si particles in centrifugal casting”, Transactions of Nonferrous Metals Society of China, 20: 361-370, (2010).
• 5. Rajan T. P. D., Pillai R. M. and Pai B. C., “Characterization of centrifugal cast functionally graded aluminum-silicon carbide metal matrix composites”, Materials Characterization, 61: 923-928, (2010).
• 6. Rahvard M. M., Tamizifar M., Boutorabi S. M. A. and Shiri S. G., “Characterization of the graded distribution of primary particles and wear behavior in the A390 alloy ring with various Mg contents fabricated by centrifugal casting”, Materials and Design, 56: 105-114, (2014).
• 7. Chumanov I. V., Anikeev A. N. and Chumanov V. I., “Fabrication of functionally graded materials by introducing wolframium carbide dispersed particles during centrifugal casting and examination of FGM’s structure”, Procedia Engineering, 129: 816-820, (2015).
• 8. Watanabe Y., Kim I.S. and Fukui Y., “Microstructures of functionally graded materials fabricated by centrifugal solid-particle and in-situ methods”, Metals and Materials International, 11: 391-399, (2005).
• 9. Arsha A. G., Jayakumar E., Rajan T. P. D., Antony V. and Pai B. C., “Design and fabrication of functionally graded in-situ aluminum composites for automotive pistons”, Materials and Design, 88: 1201-1209, (2015).
• 10. Reis B. P., França R. P., Spim J. A., Garcia A., DaCosta E. M. and Santos C. A., “The effects of dendritic arm spacing (as-cast) and aging time (solution heat-treated) of Al-Cu alloy on hardness”, Journal of Alloys and Compounds, 549: 324-335, (2013).
• 11. Houria M. I., Nadot Y., Fathallah R., Roy M. and Maijer D. M., “Influence of casting defect an SDAS on the multiaxial fatigue behaviour of A356-T6 alloy including mean stress effect”, International Journal of Fatigue, 80: 90-102, (2015).
• 12. Ceschini L., Morri A., Toschi S., Johansson S. and Seifeddine S., “Microstructural and mechanical properties characterization of heat treated and overaged cast A354 alloy with various SDAS at room and elevated temperature”, Materials Science & Engineering A, 648: 340-349, (2015).
• 13. Watanabe Y. and Oike S., “Formation mechanism of graded composition in Al-Al2Cu functionally graded materials fabricated by a centrifugal in situ method”, Acta Materialia, 53: 1631-1641, (2005).
• 14. Watanabe Y., Hattori Y. and Sato H., “Distribution of microstructure and cooling rate in Al-Al2Cu functionally graded materials fabricated by a centrifugal method”, Journal of Materials Processing Technology, 221: 197-204, (2015).
• 15. Lin X., Liu C. and Xiao H., “Fabrication of Al-Si-Mg functionally graded materials tube reinforced with in situ Si/Mg2Si particles by centrifugal casting”, Composites: Part B, 45: 8-21, (2013).
• 16. Huang X., Liu C., Lv X., Liu G. and Li F., “Aluminum alloy pistons reinforced with SiC fabricated by centrifugal casting”, Journal of Materials Processing Technology, 211: 1540-1546, (2011).
• 17. Akar N., Şahin H. M., Yalçin N. and Kocatepe K., “Experimental study on the effect of liquid metal superheat and casting height on interfacial heat transfer coefficient”, Experimental Heat Transfer, 21(1): 83-98, (2008).
• 18. Şahin H. M., Kocatepe K., Kayıkcı R. and Akar N., “Determination of Unidirectional Heat Transfer Coefficient during Unsteady-State Solidification at Metal Casting–Chill Interface”, Energy Conversion and Management, 47(1): 19-34, (2006).
• 19. Akar N., Boran K. and Hozikliğil B., "Effect of Mold Temperature on Heat Transfer Coefficient at Casting-Mold Interface", Journal of the Faculty of Engineering & Architecture of Gazi University, 28(2): 275-282, (2013).