Influences of extrusion temperatures on the wear behavior of magnesium alloy AZ31 fabricated by the extrusion shear process

Abstract

Abstract The wear resistance of as-cast AZ31 magnesium alloy samples fabricated by extrusion shear (ES) with various preheating temperatures (420, 400, 370 °C) of billets was tested by using pin-on-disc experiments under dry sliding wear conditions. Wear rates and friction coefficient were measured at various sliding frequencies and normal forces. To define the wear mechanism for each tested condition, the worn surfaces were analyzed using scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS). Based on the test results, the wear resistance of the ES-processed samples decreases with drop of the billet temperatures. The friction coefficients and wear rates of the samples with a preheating temperature of 370 °C are lower than those with deformation temperatures of 400 °C and 420 °C. With the increase of normal loads and reciprocating frequencies, the wear mechanism changes from mild wear (adhesion, abrasion and oxidation) to severe wear (delamination, plastic deformation and melting). Therefore, the extrusion methods have significant influences on the wear behaviors of the samples, and the wear resistance of AZ31 magnesium alloy can be improved by ES process.