An examination of adiabatic shearing behavior in ZK60 alloy with different states of heat treatment

摘要

Adiabatic shearing behavior and fracture were investigated in ZK60 magnesium alloy by means of radial collapse of a thick-walled cylinder. The alloy was tested in the solid solution (T4), as-extruded (T5) and solid solution plus aged (T6) conditions to examine adiabatic shearing behavior. Results showed that the alloy was less susceptible to the formation of Adiabatic Shear Bands (ASBs) under the T4 condition due to the number of observed adiabatic shear bands and their corresponding average lengths. On the other hand, the alloy under the T5 condition was more susceptible to the formation of adiabatic shear bands with 39 and 41 shear bands observed under effective strains of 0.72 and 0.95 respectively. Nevertheless, the shear bands observed in the T6 condition were longer compared to all the other heat treated conditions. The widths of the ASBs are 3.8 μm, 8.56 μm and 8.62 μm at the T4, T5 and T6 states respectively. It was shown that the alloy under the different conditions provide a wide range of microstructural parameters and mechanical properties. It was shown that the ZK60 magnesium alloy under the different conditions provide a wide range of microstructural parameters (grain size, precipitates) and mechanical properties that affect its adiabatic shearing behavior. It is concluded that ASB is one of the damage fracture models under this kind of high strain rate loading where cracks nucleated on the edge of the ASBs and propagated along the shear direction.