Investigating the Effects of Expansion Equal Channel Angular Extrusion (Exp-ECAE) on Dynamic Behavior of AA7075 Aluminum Alloy

ADMT Journal

مقاله 2، دوره 9، شماره 3، آذر 2016، صفحه 11-18   

نوع مقاله: Original Article

نویسندگان

J. Shahbazi Karami¹؛ S. Sepahi-Boroujeni²؛ Mohsen Khodsetan^{* 3}

¹University of Shahid Rajaee Teacher Training, Iran

²University of Bu-Ali Sina, Iran.

³School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran. *Corresponding author

چکیده

Expansion equal channel angular extrusion (Exp-ECAE) is a severe plastic deformation (SPD) operation for processing bulk materials. In the current study, AA7075 Al was SPD-processed by expansion equal channel angular extrusion (Ex-ECAE) at various temperatures and ram velocities. Then, using split Hopkinson pressure bar (SHPB), the severely deformed products were compressed at room temperature and strain rates of 0.1~3000 s^-1. Both the strain rate sensitivity (SRS) and the apparent activation volume (AAV) were determined for all deformed samples. The results revealed that the Ex-ECAE operation has noticeably increased the SRS. The tensile strength at a strain rate of 3000 s^-1 was 6 times increased by conducting Ex-ECAE at 100 °C and with a ram velocity of 7 mm/min. Ex-ECAE was also capable of considerably decreasing the AAV. The results showed the yield stress of both the Exp-ECAE and the annealed samples increased with increasing the strain rate. Also, the results showed that after the Exp-ECAE process, the AAV reached to 6.3 b³ from the initial values of 118.5 b³ in the annealed state.

کلیدواژه‌ها

AA7075 Aluminum Alloy؛ Dynamic Behavior؛ Expansion Equal Channel Angular Extrusion؛ Hopkinson Pressure Bar؛ Severe Plastic Deformation

مراجع

[1]  Valiev, R. Z., Islamgaliev, R. K. and Alexandrov, I. V., “Bulk nanostructured materials from severe plastic deformation”, Progress in Materials Science,Vol. 45, 2000, pp. 103-189.

[2]  Pardis, N., Talebanpour, B., Ebrahimi, R. and Zomorodian, S., “Cyclic expansion-extrusion (CEE): A modified counterpart of cyclic extrusion-compression (CEC)”, Materials Science and Engineering: A, Vol. 528, 2011, pp. 7537-7540.

[3]  Torabzadeh, H., Faraji, G. and Zalnezhad, E., “Cyclic Flaring and Sinking (CFS) as a New Severe Plastic Deformation Method for Thin-walled Cylindrical Tubes”, Transactions of the Indian Institute of Metals, 2015, pp. 1-6.

[4]  Suo, T., Chen, Y., Li, Y., Wang, C. and Fan, X., “Strain rate sensitivity and deformation kinetics of ECAPed aluminium over a wide range of strain rates”, Materials Science and Engineering: A,Vol. 560, 2013, pp. 545-551.

[5]  Meyers, M. A., Mishra, A. and Benson, D. J., “Mechanical properties of nanocrystalline materials”, Progress in Materials Science,Vol. 51, 2006, pp. 427-556.

[6]  Ferguson, W. G., Kumar, A. and Dorn, J. E., “Dislocation Damping in Aluminum at High Strain Rates”, Journal of Applied Physics,Vol. 38, 1967, pp. 1863-1869.

[7]  Kumar, A., Hauser, F. E. and Dorn, J. E., “Viscous drag on dislocations in aluminum at high strain rates”, Acta Metallurgica,Vol. 16, 1968, pp. 1189-1197.

[8]  Chinta Babu, U., Prasad, K. and Kamat, S. V., “Effect of strain rate on tensile behaviour of cryo-rolled ultrafine grained OFHC copper”, Transactions of the Indian Institute of Metals,Vol. 64, 2011, pp. 321-324.

[9]  SridharBabu, B., Kumaraswamy, A., and AnjaneyaPrasad, B., “Effect of Indentation Size and Strain Rate on Nanomechanical Behavior of Ti-6Al-4VAlloy”, Transactions of the Indian Institute of Metals,Vol. 68, 2014, pp. 143-150.

[10]        Fereshteh-Saniee, F., Sepahi-Boroujeni, S., Lahmi, S. and Majzoobi, G. H., “An Experimental Investigation on the Strain Rate Sensitivity of a Severely Deformed Aluminum Alloy”, Experimental Mechanics,Vol. 55, 2015, pp. 569-576.

[11]        Sepahi-Boroujeni S. Fereshteh-Saniee, F., “Expansion equal channel angular extrusion, as a novel severe plastic deformation technique”, Journal of Materials Science,Vol. 50, 2015, pp. 3908-3919.

[12]        Kolsky, H., “An Investigation of the Mechanical Properties of Materials at very High Rates of Loading”, Proceedings of the Physical Society. Section B,Vol. 62, 1949, pp. 676.

[13]        Krausz, A. S. Krausz, K., “Unified Constitutive Laws of Plastic Deformation”, San Diego, California: Elsevier Science, 1996.

[14]        Wei, Q., Jiao, T., Mathaudhu, S. N., Ma, E., Hartwig, K. T. and Ramesh, K. T., “Microstructure and mechanical properties of tantalum after equal channel angular extrusion (ECAE)”, Materials Science and Engineering: A,Vol. 358, 2003, pp. 266-272.

[15]        Valiev, R. Z. Langdon, T. G., “Principles of equal-channel angular pressing as a processing tool for grain refinement”, Progress in Materials Science,Vol. 51, 2006, pp. 881-981.

[16]        Kapoor, R., Singh, J. B. and Chakravartty, J. K., “High strain rate behavior of ultrafine-grained Al–1.5 Mg”, Materials Science and Engineering: A,Vol. 496, 2008, pp. 308-315.

[17]        Suo, T., Li, Y. l, Xie, K, Zhao, F., Zhang, K. S. and Deng, Q., “Experimental investigation on strain rate sensitivity of ultra-fine grained copper at elevated temperatures”, Mechanics of Materials, Vol. 43, 2011, pp. 111-118.

[18]        Wolfer, W. G., “Phonon Drag Dislocations at High Pressures”, UCRL-ID-136221; TRN: US0204469, 1999.

[19]      Kumar, A. Kumble, R. G., “Viscous Drag on Dislocations at High Strain Rates in Copper”, Journal of Applied Physics,Vol. 40, pp. 3475-3480, 1969.