PNNL

Abstract

Friction extrusion is a metal forming process that generates large plastic strains and deformation-induced heating through friction between a rotating die and the material to be extruded. The final deformation state in friction extruded wire has been visualized in previous studies. However, the distribution and evolution of the strain and strain rate during the process have yet to be elucidated. This paper discusses an approach that reveals the deformation during the process by visualizing the shape change of markers in the remnant billet. For the first time, the distribution of steady-state strain and strain rate in friction extrusion is obtained. The trend of strain and strain rate evolution from the undeformed zone to the extrusion die opening is revealed. The geometry of deformation zone and “dead metal” zone are deduced. The effects of billet material and processing parameters on the deformation evolution are discussed.