Effect of Compression Passes on Mechanical Properties and Corrosion Behavior of ZK60 Magnesium Alloy

Abstract:

The impact of multi-directional compression passes on the microstructure, mechanical properties, and corrosion behavior of ZK60 magnesium alloy was investigated. Results reveal that severe dendrite segregation exists in the as-cast ZK60 magnesium alloy with coarse MgZn phases distributed along the grain boundaries. After 9 passes of compression, the coarse solidified phases at the grain boundary are significantly refined, and back dissolution occurs. Fine recrystallized grains accompanied with the fine diffused nano-phases emerge in the local area around the large grains. The tensile strength of ZK60 magnesium alloy generally exhibits the upward trend with the increase in compression passes, whereas the compression rate shows the downward trend. The compressive strength reaches 433.6 MPa with the compression rate of 21.3% after 9 passes of compression. Multi-directional compression can significantly reduce the degradation rate of ZK60 magnesium alloy in simulated body fluids. Furthermore, it is observed that in the as-cast ZK60 magnesium alloy, micro-segregation can easily lead to severe intragranular local corrosion. However, after multi-directional compression, the tendency to intragranular local corrosion is significantly diminished.