Equal channel angular pressing (ECAP) is carried out using two different configurations for the exit channel of the ECAP die, i.e., relieved and choked, with angles of 0.2 °. It is found that using a die with relieved exit channel, the sample was extruded for 6 passes with no surface cracks and an average cell size of 727 nm and a fraction of high angle grain boundaries of 54 % were achieved. M...

shape error due to elastic recovery of formed part in unloading known as springback, is one of the most important problems of tool design in sheet metal forming processes. many researches have been performed for proposing an efficient method to decrease or compensate springback error in sheet forming processes. these methods are usually based on iterative finite element algorithms. in this pape...

In this paper, an analytical method for noncircular shape extrusion is presented. Using this method, non-linear deformation field can be described with Hermit cubic spline which is prescribed by the boundary conditions of the die at its entryand exit. The upper bound method has been used to obtain optimum coefficient of the tangential boundary conditions. The results show that the optimum tange...

In this paper, an analytical method for noncircular shape extrusion is presented. Using this method, non-linear deformation field can be described with Hermit cubic spline which is prescribed by the boundary conditions of the die at its entryand exit. The upper bound method has been used to obtain optimum coefficient of the tangential boundary conditions. The results show that the optimum tange...

Prediction of the deformation characteristics is an important step to understand the workability of alloys during imposing large strains. In this research, severe plastic deformation of Sn-5Sb solder alloy was carried out under different t deformation conditions, including the temperature range of 298, 330, 36, 400 K and die designs. The current study applies an experimentally validated finite ...

The main limitation of the Equal Channel Angular Pressing (ECAP) is very high required punching force for pushing metallic sample to next channel. Frictional forces in ECAP process are responsible force. participation exit and entrance channels total friction has not been studied experimentally hitherto. Through current study, two dies (1) with (normal die) (2) only one channel (the was missed)...

Since tubes have numerous industrial applications, different attempts are focused on the Severe Plastic Deformation (SPD) processes of tubes. As an illustration, Tube Channel Pressing (TCP) is an attractive process for this purpose since it can be used for processing of different sizes of tubes. However, more attempts are needed to improve the outcomes of TCP. For example, imposing of greater s...

Institutionalizing Eurozone Exit: A modified NEWNEY approach Steffen Huck, Justin Mattias Valasek* In this note, we argue that the Eurozone needs an institutional exit mechanism to enhance Eurozone stability, and propose modifications to the Dobbs' NEWNEY mechanism, the only mechanism that satisfies the twin properties of eliminating incentives for intra-Eurozone capital flight and maintaining ...

Since tubes have numerous industrial applications, different attempts are focused on the severe plastic deformation processes of tubes. As an illustration, tube channel pressing (TCP) is an attractive process for this purpose since it can be used for processing of different sizes of tubes. However, more attempts are needed to improve the outcomes of TCP. For example, imposing of a greater strai...