The Influence of ECAP Geometry on the Effective Strain Distribution

Article Preview

Abstract:

Equal channel angular pressing (ECAP) is one of the most well-known severe plastic deformation (SPD) method for formation the UFG (ultrafine-grained) structures. This method provides very high strains leading to the extreme work hardening and microstructural refinement. To increase the efficiency of ECAP method, there is necessary to design the geometry of ECAP die with focus on high degree of plastic deformation homogeneity. The present study deals with the influence of channel angle on the deformation behavior and strain homogeneity in the transverse direction of sample after two ECAP passes. This analysis was carried out through finite element simulations in the Deform program. In the simulation, three main factors such as an intersecting angle of Ф = 90°, 100°, 110° a 120°, outer corner angle R (ψ) and inner corner angle (r) were being varied. The equation describing the dependence of R and r on average value of the effective plastic strain for different channel angles was established. Moreover, strain inhomogeneity index (Ci) in the transverse direction of sample was also calculated. The results from simulations have indicated that if the outer corner angle increases, mean effective strain decreases. After two ECAP passes (route C), there was seen the increase in strain homogeneity of the sample's cross section.

You might also be interested in these eBooks

Info:

Periodical:

Pages:

135-141

Citation:

Online since:

October 2015

Export:

Price:

* - Corresponding Author

[1] Valiev, R.Z., Islamgaliev, R.K., Alexandrov, I.V. Bulk Nanostructured Materials from Severe Plastic Deformation. Progress in Materials Science, Vol. 45, 2000, pp.103-189.

DOI: 10.1016/s0079-6425(99)00007-9

Google Scholar

[2] Furukawa, M., Iwahashi, Y., Horita, Z., Nemoto, M., Langdon, T.G. The shearing characteristics associated with equal-channel angular pressing. Materials Science and Engineering, Vol. A257, 1998, pp.328-332.

DOI: 10.1016/s0921-5093(98)00750-3

Google Scholar

[3] Kvačkaj, T., Kováčová, A., Kvačkaj, M., Pokorný, I., Kočiško, R., Donič, T. Influence of strain rate on ultimate tensile stress of coarse-grained and ultrafine-grained copper. Materials Letters, Volume 64, Issue 21, 15 November 2010, pp.2344-2346.

DOI: 10.1016/j.matlet.2010.07.047

Google Scholar

[4] Vinogradov, A., Kaneko, Y., Kitagawa, K., Hashimoto, S., Valiev, R. On the cyclic response of ultrafine-grained copper. Materials Science Forum, Vol. 269, 1998, p.987–992.

DOI: 10.4028/www.scientific.net/msf.269-272.987

Google Scholar

[5] Bidulský, R., Bidulská, J., Actis Grande M. Effect of High-Temperature Sintering and Severe Plastic Deformation on the Porosity Distribution. High Temperature Materials and Processes, 2009, Vol. 28, No. 5, pp.337-342.

DOI: 10.1515/htmp.2009.28.5.337

Google Scholar

[6] Zhu, Y.T., Lowe, T.C., Langdon, T.G. Performance and applications of nanostructured materials produced by severe plastic deformation. Scripta Materialia, 51, 2004. pp.825-830.

DOI: 10.1016/j.scriptamat.2004.05.006

Google Scholar

[7] Xua, Ch., Furukawab, M., Horitac, Z., Langdon, T. G. Severe plastic deformation as a processing tool for developing superplastic metals. Journal of Alloys and Compounds. Volume 378, Issues 1–2, 22. September 2004, p.27–34.

DOI: 10.1016/j.jallcom.2003.10.065

Google Scholar

[8] Matvija, M., Fujda, M., Milkovič, O., Kvačkaj, T., Vojtko, M., Zubko, P., Kočiško, R., The effect of ECAP and subsequent Post-ECAP annealing on the microstructure and mechanical properties of AlSi7Mg0. 3 alloy. Acta Metallurgica Slovaca, 2012, vol. 18, No. 1, pp.4-12.

DOI: 10.12776/amsc.v3i0.109

Google Scholar

[9] Navrátilová, L., Kunz, L., Nový, F., Mintách, R. Development of cyclic slip bands in UFG copper in gigacycle fatigue. Acta Metallurgica Slovaca, 2013, vol. 19, No. 2, pp.88-93.

DOI: 10.12776/ams.v19i2.92

Google Scholar

[10] Bidulská, J., Kvačkaj, T., Kočiško, R., Bidulský, R., Actis Grande, M., Donič, T., Martikán, M. Influence of ECAP-back pressure on the porosity distribution. Acta Physica Polonica A, 2010, vol. 117, No. 5, pp.864-868.

DOI: 10.12693/aphyspola.117.864

Google Scholar

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

DOI: 10.1016/j.pmatsci.2006.02.003

Google Scholar

[12] Kim, W.J., Namkung, J.C. Computational analysis of effect of route on strain uniformity in equal channel angular extrusion. Materials Science and Engineering. A 412, 2005, p.287–297.

DOI: 10.1016/j.msea.2005.08.222

Google Scholar

[13] Medeiros, N., Moreira, L.P. Upper-bound analysis of die corner gap formation for strain-hardening materials in ECAP process. Computational Materials Science. 91, 2014, p.350–35.

DOI: 10.1016/j.commatsci.2014.05.012

Google Scholar

[14] Cerri, E., De Marco, P.P., Leo, P. FEM and metallurgical analysis of modified 6082 aluminium alloys processed by multipass ECAP: Influence of material properties and different process settings on induced plastic strain. Journal of materials processing technology, 209, 2009, p.1550.

DOI: 10.1016/j.jmatprotec.2008.04.013

Google Scholar

[15] Lu, S. K., Liu, H. Y., Yub, L., Jiang, Y.L., Su, J. H. 3D FEM simulations for the homogeneity of plastic deformation in aluminum alloy HS6061-T6 during ECAP. Procedia Engineering, 12, 2011, p.35–40.

DOI: 10.1016/j.proeng.2011.05.007

Google Scholar

[16] Mahallawy, N.E., Shehata, F.A., Hameed, A.E., Abd El Aal, M.I., Kim, H.S. 3D FEM simulations for the homogeneity of plastic deformation in Al–Cu alloys during ECAP. Materials Science and Engineering, A 527, 2010, p.1404–1410.

DOI: 10.1016/j.msea.2009.10.032

Google Scholar

[17] KVAČKAJ, T., KOČIŠKO, R., KOVÁČOVÁ, A. Local analysis of plastic deformation in ECAP and ECAR processes. Chemické Listy, 106, 2012, p.464 - s467.

Google Scholar

[18] Oh, S.J., Kang, S.B. Analysis of the billet deformation during equal channel angular Pressing. Materials Science and Engineering, A343, 2003, pp.107-115.

DOI: 10.1016/s0921-5093(02)00324-6

Google Scholar

[19] Bidulská, J., Kočiško, R., Kvačkaj, T., Bidulský, R., Actis Grande, M. Simulácie ECAP procesu zliatiny EN AW 2014 pomocou MKP. Chemické Listy, 105, 2011, pp.155-158.

DOI: 10.4028/www.scientific.net/msf.667-669.535

Google Scholar

[20] Djavanroodi, F., Ebrahimi, M. Effect of die parameters and material properties in ECAP with parallel channels. Materials Science and Engineering, , A 527, 2010, p.7593–7599.

DOI: 10.1016/j.msea.2010.08.022

Google Scholar

[21] Li, S., Beyerlein, I.J., Necker, C.T., Alexander, D.J., Bourke, M. Heterogeneity of deformation texture in equal channel angular extrusion of copper. Acta Materialia. 52, 2004, p.4859–4875.

DOI: 10.1016/j.actamat.2004.06.042

Google Scholar