Non-equal Channel Multi Angular Extrusion (NECMAE) – Part 2: The Role of Friction and Heat Generation due to Plastic Deformation

Abstract

Among the procedures developed for structure grain refinement, equal channel angular extrusion techniques experience a great popularity, owing to its proficiency to produce significant grain refinement in fully dense bulk-scale materials. It is essential to compromise between the design of die and processing parameters to estimate a homogeneous deformation, optimize the strain distribution, and load requirement. In this regard, numerical modelling has been done to comprehend the impact of temperature and friction on the newly developed plastic deformation technique known as "nonequal channel multi-angular extrusion" (NECMAE), which experienced a cross-sectional area reduction on the subsequent channel. Three friction coefficients were examined combined with heat generation analysis to evaluate the plastic strain homogeneity. The preliminary results obtained show that 30% reduction case with µ=0.1 has the most uniform strain distribution across the workpiece and improves strain homogeneity significantly by 6 times greater than the frictionless case. In general, the optimum strain distribution could be achieved by using the right combination of area reduction and frictional conditions. The analysis implies that plastic strain, temperature, and required load are significantly affected by localized plastic deformation zone and the incrementation of heat generated. Current study opens the opportunity to satisfy the workpiece hardening level due to different localizations of plastic deformation of the proposed die design.

Keywords

• severe plastic deformation (spd)
• finite element modelling (fem)
• equal channel angular extrusion (ecae)
• friction coefficient