Microstructure Evolution of Peak-Aged ZK60 Magnesium Alloy under High Strain Rate Deformation

Abstract

The microstructure evolution of peak-aged ZK60 magnesium alloy under high strain rate deformation was studied by the radial collapse of a thick-walled cylinder technique and transmission electron microscope. The results showed that the rod-like β₁^’ phase was the main precipitated phase in the peak-aged ZK60 magnesium alloy, and precipitate-free regions were present along the grain boundaries. A large number of twins and dislocations were produced in the sample within 4.0 μs after high strain rate loading, and a number of thin and long rod-like β₁^’ phases were observed within the dislocated tangle of the deformed sample. The length and diameter of the rod-like phases in the samples were gradually reduced, and some of the rod-like phases were converted into spherical phases with increasing strain rate, which indicated that the original precipitated phases were partly dissolved after high strain rate loading. The microhardness of the samples increased from HV80.12 to HV101.20 as the strain rate increased.