Buradasınız

Anasayfa » Content

EŞİT KANAL-AÇISAL PRESLEME (EKAP) YÖNTEMİYLE AŞIRI DEFORMASYON YAPILMIŞ 7075 ALÜMİNYUM ALAŞIMININ MİKROYAPISAL KARAKTERİZASYONU

MICROSTRUCTURAL CHARACTERIZATION OF 7075 ALUMINUM ALLOY SEVERE DEFORMED BY EQUAL CHANNEL-ANGULAR PRESSING (ECAP)

Journal Name:

  • Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

Publication Year:

  • 2012

Key Words:

Keywords (Original Language):

Author NameUniversity of AuthorFaculty of Author
Abstract (2. Language): 
In this study; Equal Channel Angular Pressing (ECAP) process for 7075 aluminum alloy were succesfully carried out up to 14 passes at 200 oC and at pressing speed of 2 mms-1 by using Route C. After ECAP processes, the specimens were characterized by Transmission Electron Microscope (TEM), hardness and macrostructural investigations. Macrostructural investigations showed that the plastic deformation in the ECAPed specimens occurred from edge to the centre, clock wise and like whirlpool. In addition, the deformation intensity increased with increasing pass number. The mean grain size of the specimens was effectively decreased with increasing ECAP pass number.That is, while the grain size of unECAPed specimen was 10 μm, this value was decreased to 300 nm at the 14th pass. At the beginning, while there was a banding tendency in the grains toward deformation direction, homogeneous and equ-axed grains were formed by increasing pass number. Hardness results showed that the hardness values increased up to 4 passes, decreased effectively at 6th pass, again increased 8th pass and after this pass, the hardness was again decreased due to dynamic recrystallization.
Bookmark/Search this post with
Abstract (Original Language): 
Bu çalışmada, 7075 Al alaşımı Eşit Kanal-Açısal Presleme (EKAP) yöntemi ile 200 °C’de 2 mm/s presleme hızında ve Rota C kullanılarak 14 pasa kadar başarılı bir şekilde deforme edilmiştir. EKAP işleminden sonra numuneler TEM (Geçirimli Elektron Mikroskobu), makroyapı ve sertlik incelemeleri ile karakterize edilmiştir. Makroyapı incelemeleri, EKAP yapılmış numunelerde plastik deformasyonun kenardan merkezine doğru, saat yönünde ve girdap şeklinde olduğunu göstermiştir. Ayrıca, deformasyonun şiddeti artan pas sayısı ile artmıştır. EKAP pas sayısındaki artışla numunelerin ortalama tane boyutu etkili bir şekilde azalmıştır. Şöyle ki; EKAP yapılmamış numunedeki tane boyutu ~10 μm iken bu değer 14 pasta ~300 nm’e inmiştir. Başlangıçta tanelerde deformasyon yönünde bir bantlaşma eğilimi varken, artan paso sayısıyla daha homojen ve daha eş kesimli taneler oluşmuştur. Sertlik sonuçları,4. pasa kadar sertliğin arttığını, 6. pasta etkili bir şekilde azaldığını, 8. pasta yeniden arttığını ve bu pastan sonra ise dinamik yeniden kristalleşme sebebiyle azaldığını göstermiştir.
FULL TEXT (PDF): 
PDF icon arastirmax-esit-kanal-acisal-presleme-ekap-yontemiyle-asiri-deformasyon-yapilmis-7075-aluminyum-alasiminin-mikroyapisal-karakterizasyonu.pdf
  • 4
807
812
  • Turkish

REFERENCES

References: 

1. Furui, M., Kitamura, H., Anada, H., Langdon,
T.G., “Influence of Preliminary Extrusion
Conditions on the Superplastic Properties of a
Magnesium Alloy Processed by ECAP”, Acta
Materialia,Cilt 55, 1083–1091, 2007.
2. Málek, P., Cieslar, M., Islamgaliev, R.K., “The
Influence of ECAP Temperature on the Stability of
Al–Zn–Mg–Cu Alloy”, Journal of Alloys and
Compounds, Cilt 378, 237–241, 2004.
3. Valiev, R.Z., Langdon, T.G., “Principles of Equal-
Channel Angular Pressing as a Processing Tool for
Grain Refinement”, Progress in Materials
Science, Cilt 51, No 7, 881–981, 2006.
4. Lowe, T., Zhu, Y., “Commercialism of
Nanostructured Metals Produced by Severe Plastic
Deformation Processing”, Advanced Engineering
Materials, Cilt 5, 373-378, 2003.
5. Valiev, R. Z., Langdon, T.G., “Principles of Equal-
Channel Angular Pressing as a Processing Tool for
Grain Refinement”, Progress in Materials
Science, Cilt 51, 881–981, 2006.
6. Valiev, R.Z., Alexandrov, I.V., Zhu, Y.T., Lowe,
T.C., “Paradox of Strength and Ductility in Metals
Processed By Severe Plastic Deformation”,
Journal of Materials Research, Cilt 17, 5-8,
2002.
7. Zheng, L.J., Chen, C.Q., Zhou, T.T., Liu, P.Y.,
Zeng, M.G., “Structure and Properties of Ultrafine-
Grained Al-Zn-Mg-Cu and Al-Cu-Mg-Mn Alloys
Fabricated by ECA Pressing Combined with
Thermal Treatment”, Materials
Characterization, Cilt 49, 455– 461, 2003.
8. Nagarajan, D., Chakkingal, U., Venugopal, P.,
“Influence of Cold Extrusion on the Microstructure
and Mechanical properties of an Aluminium Alloy
Previously Subjected to Equal Channel Angular
Pressing”, Journal of Materials Processing
Technology, Cilt 182, 363–368, 2007.
9. Petch, N.J., “The Cleavage Strength of
Polycrystals”, Journal of the Iron and Steel
Institute, Cilt 174 (8), 25-28, 1953.
10. Purcek, G., Saray, O., Karaman, I.,
Kucukomeroglu, T., “Effect of Severe Plastic
Deformation on Tensile Properties and Impact
Toughness of Two-Phase Zn–40Al Alloy”,
Materials Science and Engineering A, Cilt 490,
403–410, 2008.

Thank you for copying data from http://www.arastirmax.com