Theoretical analysis of equal channel angular pressing method for grain refinement of metals and alloys Krishna Mohan Agarwal a,⇑ , R.K. Tyagi a , Anurag Dixit b a Mechanical Engineering Department, Amity University, Uttar Pradesh, Noida 201303, India b Mechanical & Automation Engineering Department, G B Pant Govt Engineering College, New Delhi 110020, India article info Article history: Received 18 March 2019 Received in revised form 6 June 2019 Accepted 1 August 2019 Available online xxxx Keywords: Ultra-fine grain structure Severe plastic deformation Equal channel angular pressing (ECAP) Grain refinement Aluminium alloys Mechanical properties abstract The most innovative ECAP method is used for grain refinement of bulk crystalline material to ultrafine structure and subsequent improvement in mechanical properties of materials. In this research paper, dis- cussion has been made about the exertion of earlier researchers related to improvement of microstruc- ture and mechanical properties for industrial fabrication. In general, the result obtained shows that this method is useful for grain refinement up-to certain level due to high imposed shear strain. It has also been observed that strength is also increased with ductility as desired in most of the cases. Ó 2019 Elsevier Ltd. All rights reserved. Peer-review under responsibility of the scientific committee of the 2nd International Conference on Computational and Experimental Methods in Mechanical Engineering. 1. Introduction Almost all the components bear either static or dynamic loading during service and the components fail due to poor mechanical properties and that is the reason we require good mechanical strength and better ductility. So in this research paper, our focus is to gather information regarding, to produce the material of desirable properties so that these failures can be minimized. The study shows that grain refinement through severe plastic deforma- tion can be utilized to improve the mechanical properties. There are number of methods of severe plastic deformation. ECAP the most innovative severe plastic deformation method was initially founded by Segal in 1980s in the former Soviet Union which in the later years was developed by Valiev and co-workers in order to refine the microstructure which results in the improvement of mechanical behaviour in materials by grain refinement. The beauty of this method lies in its ability to improve the mechanical beha- viour of material without any change in the dimension as com- pared to traditional deformation methods. This method involves two equal channels that meet at some angle, which is usually between 90 0 and 135 0 . Then after a billet is extruded through the channels and as the billet crosses the main deformation zone, the deformation is produced by simple shear which is method of defor- mation for structure and texture formation in metal forming pro- cess [1–8]. In last decades, lot of activities related to metal forming/severe plastic deformation shows interest in the mechanical properties of micro crystalline, ultrafine grained (UFG) and Nano crystalline materials in the size range of micro meter and sub micro meter even at Nano meter level [9–20]. It is now an established fact that the grain size of metals and alloys may be substantially refined by the application of severe plastic deformation using ECAP. The mechanical and physical properties can describe any material and these can be determined by several factors. The average grain size of the material plays an important role and often dominant role in defining strength of the material. The strength of the mate- rial can be increased by decreasing the average grain size of the material and this can be explained by the well-known Hall–Petch equation. The relation for yield stress r y with grain size is given in Eq. (1): r y ¼ r 0 þ kd 1=2 ð1Þ where r 0 is the friction stress and k is a yielding constant. The above relation is also termed as grain-boundary strengthening as it improves the strength. It has been observed that the grain bound- aries hamper movement of dislocation and that the number of dis- locations within a grain has an effect on how easily dislocations can https://doi.org/10.1016/j.matpr.2019.08.026 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Peer-review under responsibility of the scientific committee of the 2nd International Conference on Computational and Experimental Methods in Mechanical Engineering. ⇑ Corresponding author. E-mail address: profkmagarwal@gmail.com (K. Mohan Agarwal). Materials Today: Proceedings xxx (xxxx) xxx Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr Please cite this article as: K. Mohan Agarwal, R. K. Tyagi and A. Dixit, Theoretical analysis of equal channel angular pressing method for grain refinement of metals and alloys, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.08.026