Preparation of Super-High Strength Bimodal Aluminum Based Nanocomposite Via Mechanical Alloying and Hot Extrusion

Subject Areas : journal of New Materials

A. Abdollahi ¹ (دانشجوی کارشناسی ارشد مهندسی مواد مرکب دانشگاه صنعتی مالک اشتر، تهران.)
A. Alizadeh ² (استادیار، مجتمع مواد و فناوریهای ساخت دانشگاه صنعتی مالک اشتر، تهران.)

Received: 2013-09-16 Accepted : 2013-09-16 Published : 2013-09-23

Keywords: Al2024 Alloy, Bimodal Composite, mechanical alloying, Hot Extrusion,

Abstract :

In this paper, bimodal Aluminum based nanocomposite prepared via mechanical alloying and hot extrusion. Mechanical alloying was used to synthesize Al2024 nanostructured powder in attrition mill under argon atmosphere up to 50 h. After mixing nanostructured aluminum and unmilled aluminum powders in low energy ball mill, the resulting composite powders were shaped through hot Pressing. Finally, the hot pressed powders were hot extruded. The microstructure and fracture surface were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM) equipped with energy dispersive X-ray spectrometry (EDS). In order to compare the mechanical properties of hot extruded samples, tensile, compression, and hardness tests were performed. Results showed that, with an increase in unmilled aluminum percentage, ductility of composite increased but strength and hardness decreased. The mechanisms for the simultaneously improved strength and ductility involves increased dislocation activity in the coarse-grained (i.e., unmilled powder) regions as a result of the constraint of plastic deformation in these coarse-grained regions.

References:

1- B. Ahn, and S.R. Nutt, “Strain Mapping

of Al–Mg Alloy with Multi-scale Grain

Structure using Digital Image Correlation

Method”, Experimental Mechanics, Vol.

50, pp 117–123, 2010.

2- Z. Lee, D.B. Witkin, V. Radmilovic,

E.J. Lavernia, and S.R. Nutt, “Bimodal

microstructure and deformation of

cryomilled bulk nanocrystalline Al–7.5Mg

alloy”; Materials Science and Engineering

A, Vols. 410–411, pp 462–467, 2005.

3- D. Witkin, B.Q. Han, and E.J. Lavernia,

“Mechanical Behavior of UltrafineGrained Cryomilled Al 5083 at Elevated

Temperature”; Journal of Materials

Engineering and Performance, Vol. 14, pp

519-527, 2005.

4- D. Witkin, B.Q. Han, and E.J. Lavernia,

“Room-Temperature Mechanical Behavior

of Cryomilled Al Alloys”; Metallurgical

and Materials Transactions A, Vol. 37, pp

185-194, 2006.

5- A. Yamashita, D. Yamaguchi, Z. Horita,

and T.G. Langdon, "Influence of pressing

temperature on microstructural

development in equal channel angular

pressing"; Materials Science and

Engineering A, Vol. 287, pp 100–106,

2000.

6- J.H. Ahn, Y.J. Kim, and H. Chung, “AlAlN Tri-modal Composites prepared by

Mechanical Alloying”, Rev. Adv. Mater.

Sci, Vol. 18, pp 329-334, 2008.

7- D. Witkin, Z. Lee, R. Rodriguez, S.

Nutt, and E. Lavernia, “Al–Mg alloy

engineered with bimodal grain size for

high strength and increased ductility”,

Scripta Materialia, Vol. 49, pp 297–302,

2003.

8- C. Hofmeister, B. Yao, Y.H. Sohn, T.

Delahanty, M. Bergh, and K. Cho,

“Composition and structure of nitrogencontaining dispersoids in trimodal

aluminum metal–matrix composites”,

Journal of Materials Science, Vol. 45, pp

4871–4876, 2010.

9- B.Q. Han, J. Ye, F. Tang, J. Schoenung,

and E.J Lavernia, “Processing and

behavior of nanostructured metallic alloys

and composites by Cryomilling”, Journal

of Materials Science, Vol. 42, pp 1660–

1672, 2007.

10- R.W. Hayes, D. Witkin, F. Zhou, and

E.J. Lavernia, “Deformation and activation

volumes of cryomilled ultrafine-grained

aluminum”, Acta Materialia, Vol. 52, pp

4259–4271, 2004.

11- S.S. Razavi Tousi, R. Yazdani Rad, E.

Salahi, I. Mobasherpour, and M. Razavi,

“Production of Al–20 wt.% Al2O3

composite powder using high energy

milling”, Powder Technology, Vol. 192,

pp 346–351, 2009.

12 -ر. اسدیفرد، ن. پروین، ج. آقازاده و پ. صفارزاده،

"بررسی تأثیر فرایند آلیاژسازی مکانیکی بر مورفولوژی و

اندازه دانه پودرهای کامپوزیتی SiCp-Al6061"؛

هشتمین کنگره سالانه انجمن مهندسین متالورژی ایران؛

دانشکده مهندسی مواد دانشگاه صنعتی اصفهان؛ مهرماه

.1383

13- J.B. Fogagnolo, F. Velasco, M.H.

Robert, and J.M. Torralba, “Effect of

mechanical alloying on the morphology,

microstructure and properties of

aluminium matrix composite powders”,

Materials Science and Engineering A, Vol.

342, pp 131-143, 2003.

14 -ع. علیزاده، "ساخت و بررسی خواص مکانیکی و

سایشی نانوکامپوزیت B4C-Al ،"پایاننامه دکتری،

دانشکده فنی و مهندسی دانشگاه تربیت مدرس، 1390 .

15- N. Zhao, P. Nash, and X. Yang, “The

effect of mechanical alloying on SiC

distribution and the properties of 6061

aluminum composite”, Journal of

Materials Processing Technology, Vol.

170, pp586-592, 2005.

16- G.J. Fan, H. Choo, P.K. Liaw, and E.J.

Lavernia, “Plastic deformation and fracture

of ultrafine-grained Al–Mg alloys with a

bimodal grain size distribution”; Acta

Materialia, Vol. 54, pp 1759–1766, 2006.

17 -ن. نصیریان و خ. رنجبر، "بررسی خواص مکانیکی و

ریزساختاری کامپوزیت Brass/Al ساخته شده به روش

اتصال نوردی تجمعی" مجله مواد نوین، جلد 3 ،شماره 1،

 .1391 پاییز، 54 -45 صص

18- R.G. Vogt, Z. Zhang, T.D. Topping,

E.j. Lavernia, and J.M. Schoenung,

“Cryomilled aluminum alloy and boron

carbide nano-composite plate”, Journal of

Materials Processing Technology, Vol.

209, pp 5046–5053, 2009.