Available online 11 January 2023
Abstract
Based on the deforming technique of severe plastic deformation (SPD), the grain refinement of a Mg-9Gd-3Y-2Zn-0.5Zr alloy treated with
decreasing temperature reciprocating upsetting-extrusion (RUE) and its
influence on the mechanical properties and wear behavior of the alloy
were studied. The RUE process was carried out for 4 passes in total,
starting at 0 °C and decreasing by 10 °C for each pass. The results
showed that as the number of RUE passes increased, the grain refinement
effect was obvious, and the second phase in the alloy was evenly
distributed. Room temperature tensile properties of the alloy and the deepening of the RUE degree showed a positive
correlation trend, which was due to the grain refinement, uniform
distribution of the second phase and texture weakening. And the microhardness of the alloy showed that the microhardness of RUE is the largest in 2
passes. The change in microhardness was the result of dynamic
competition between the softening effect of DRX and the work hardening
effect. In addition, the wear resistance of the alloy showed a positive
correlation with the degree of RUE under low load conditions. When the
applied load was higher, the wear resistance of the alloy treated with
RUE decreased compared to the initial state alloy. This phenomenon was
mainly due to the presence of oxidative wear on the surface of the
alloy, which could balance the positive contribution of severe plastic
deformation to wear resistance to a certain extent.
