Investigation On Dynamic Mechanical Properties Of Zinc-Aluminum Alloys

This paper has studied the influence of microstructure on dynamic compression and dynamic shear properties of zinc-aluminum alloys. ZA8, ZA27, ZA35 alloys have been selected to achieve different proportions of the microstructure. The dynamic compression tests and dynamic shear tests under device different strain rates and temperatures have been done by the Hopkinson pressure bar. The influence of temperature and strain rate on the flow stress and yield strength has been analysed, the three alloys adiabatic shearing sensitive factors have been compared and the critical conditions of thermal viscoplastic instability have been derived.Flow stress and yield strength of the ZA8, ZA27, ZA35 alloys decreases with increasing temperature and increases with the increasing strain rate.Adiabatic shear sensitive is influenced by the proportion of hexagonal close-packed phase which changes with the aluminum content in the material. The adiabatic shear sensitive factor increases with increasing proportion of hexagonal phase and it means the probability of instability is bigger.Using the three thermal viscoplastic constitutive equation above, we have derived the material critical conditions of thermal viscoplastic instability. The results show a consistent trend with the sensitive factor above.