ANALYSIS OF THE TEMPERATURE EFFECT ON THE PLASTIC STRAIN OF POLYMERS DURING HIGH PRESSURE TORSION (HPT) PROCESS

Abstract

The high pressure torsion(HPT) is an efficient process to obtain enhanced microstructures viasuper-plastic deformation. In view of its optimization, it is of primeimportance to assess the relationships between processing conditions andmaterial flow. More precisely, detailed knowledge of the plastic straindistribution in the deformed material in relation to HPT processing variablesis very useful. In this context, the present work is focused primarily tohighlight the effect of the temperature on the plastic strain distribution intothe processed polymers by HPT. The effect of the sample thickness is alsostudied. To this end, the material parameters of an elasto-viscoplasticphenomenological model were derived from compressive tests at differenttemperatures and strain rates on a typical thermoplastic polymer (high densitypolyethylene (HDPE)). The distribution of the equivalent plastic strain and theloading conditions were analysed. Recommendations on process conditions wereproclaimed at the end of this work.