Simulating equal channel angular pressing of commercially pure aluminium using Johnson–Cook model

Abstract

Optimizing the Equal Channel Angular Pressing (ECAP) process for a new material can be a complex endeavour, given the multiple variables such as Coefficient of Friction (COF), channel angle, temperature, etc. To address the need for a material model that can account for temperature-dependent plastic flow, the present study applies the Johnson-Cook plasticity model for simulating ECAP. The present study reports the effects of varying the channel angle (90°, 120°, 150°) and COF (ranging from 0 to 0.15) at room temperature. The results show that the channel angle plays a significant role in influencing the behaviour of the aluminium, with stress and strain exhibiting an inverse relationship with the channel angle. Additionally, the aluminium material experiences a maximum stress distribution and higher flow stress within the COF range of 0 to 0.15 for a channel angle of 90°, as compared to 120° and 150°. This behaviour can be attributed to the restriction of movement at higher COF values. Notably, a maximum shear stress of 56 MPa was observed when the channel angle was set to 90° with a COF of 0.15. Furthermore, across all simulations involving channel angles of 90°, 120°, and 150°, an increase in COF lead to a decrease in curvature. These simulated results are consistent with existing literature. Thus, the Johnson-Cook plasticity model, with appropriate modifications, serves as a viable approach for studying the ECAP process.