Evaluation of wear and corrosion resistance of pure Mg wire produced by friction stir extrusion

Abstract

A solid-state process—friction stir extrusion (FSE) was applied to produce wires from Mg chips. The FSE process was performed using tool rotational speed of 150, 250 and 355 r/min at a constant plunge rate of 20 mm/min. The microstructural evolution, tribological behavior and corrosion resistance of the reference specimen and the friction stir extruded specimens were investigated. Microstructural characteristics of the specimens were investigated by optical microscopy (OM) and scanning electron microscopy (SEM). The evaluations of mechanical properties include microhardness and dry sliding wear test. The corrosion resistance of the extruded specimens was characterized by potentiodynamic polarization test. The results show that the extruded specimens possess good surface quality and the process is beneficial for the improvement of hardness and wear resistance of the first machined chips. The produced wires are also found to have adequate corrosion resistance. These results demonstrate that FSE is an effective strategy for converting the machined Mg chips into the usable wires.