COMPUTATIONAL AND MICROSTRUCTURAL ANALYSIS OF EQUAL-CHANNEL ANGULAR PRESSING (ECAP) PROCESS THROUGH DIFFERENT CHANNEL ANGLES

Abstract

Severe Plastic Deformation (SPD) is an innovative process capable of producing uniform plastic deformation in a variety of materials, without causing significant change in geometric shape or cross section. SPD involves simple shear deformation that is achieved by passing the work piece through a die containing two channels of equal cross section that meet at a predetermined angle usually between 90° to 135°.  Equal-Channel Angular Pressing (ECAP), a typical SPD process, has emerged as a widely known procedure for the fabrication of ultrafine-grained metals and alloys. The present work attempts to design, model and analyze ECAP dies with different channel angles viz. 90⁰, 120⁰ and 135⁰. The designed dies are modeled in SolidWorks and analyzed in COSMOS.  Computational results indicate that the SPD properties are decided based on the die angle as the strain rates produced depends on the die angles. Best strain rates and mechanical properties are achievable with increase in acuteness of the die angle accompanied by the application of high pressure. Metallurgical test results obtained from specimen processed through the fabricated dies indicate enhanced mechanical properties are feasible in ECAP processed components as compared to conventional extrusion.  Based on the product requirements superior mechanical properties can be produced in ECAP process in different dies.