A Simulation and Study on Strain Uniformity of Equal Channel Angular Pressing

The preparation of dense bulk nanostructured materials is becoming an important research subject with the development of nanostructured materials. Equal Channel Angular Pressing (ECAP) is thought to be one of the major technologies to prepare bulk nanostructured or ultra-fine grained metals, which can improve the mechanical property of materials considerably, but its processing effect was affected by many factors, such as press route, angle of channels, etc. Since some questions in the procedure of ECAP were not understood clearly, the researchers have different judgments on these factors affecting the result of ECAP processing. There were few reports about the processing condition that affect the strain uniformity, most of which deal with only 1 and 2 passes of ECAP. In present paper, a model dealing with four connective channels which can implement the continuous 4 passes ECAP processing was established firstly, the finite element software, DEFORM-3D, was used to simulate the processing of ECAP to study how the processing condition (press route and structure of die such as the channel angle and inner-arc radius) to affect the strain uniformity. Results show that the influence of press route is associated with pressing passes. In term of 4 passes pressing, route B_c has a most uniform distribution of strain, while in term of 2 passes pressing, route C can get a good strain uniformity. In addition, with the increase of channel angle and inner-arc radius, the strain uniformity was also improved considerably. So to get the best strain uniformity all the above factors should be taken into consideration.