PNNL

Abstract

Charges of melt spun AZ91E flake were indirectly extruded into tubes using shear assisted processing and extrusion (ShAPE). The effect of instrument parameters and tool features on densification and microstructural evolution was studied. At a constant extrusion ratio, the tool rotational velocity was varied from 75 to 300 rpm, and was demonstrated to reduce the forge force by a factor of four. Modification of the extrusion die face with successively more aggressive scrolled features was found to enhance material flow into the extrusion orifice which led to a 30% reduction in spindle torque. Microstructure, texture and hardness are reported for the range of rpm and scroll geometries investigated. It was observed that the ShAPE process is able to retain the average grain size of the as-spun flake (2.5-4 µm) while simultaneously imparting strong textural alignment in the resultant tube.