Effect of tool geometry on the velocity and strain rate fields in continuous rotary extrusion of magnesium AZ91 alloy

Abstract

The Continuous Rotary Extrusion (CRE) process is also known in literature under Conform TM name and it is mainly used for the continuous extrusion of aluminum and copper alloys. In the CRE process a feedstock in the form of rod, powders or chips, is fed into the groove of the rotating wheel. CRE has lot to offer when compared to other more conventional extrusion processes such as low energy input, no limit for billet length because it is a continuous process as well as improved material physical properties due to plastic deformation under constant parameters. Therefore, the CRE process is of our interest in forming Mg alloys. In the presented study, the effect of tool geometry on the velocity and strain rate fields in the deformation zone are investigated by FEM simulation of the CRE extrusion of magnesium alloys AZ91. The FEM process model was developed in commercially available DEFORM 3DTM software. The flow stress data for AZ91 magnesium alloy were obtained from reported literature. The metal flow predictions for two different feeder plate and presence of draft angle in exit die have been presented.