Dynamic mechanical behaviour of AZ31 magnesium alloy
摘要
To investigate the dynamic mechanical behavior of AZ31 Mg alloy,dynamic compression was carried out using a split Hop kinson pressure bar(SHPB) apparatus at strain rates up to 2.0×103 s-1,and d ynamic hardness was tested employing a dynamic hardness device at room temperatu re.Microstructural characteristic was analysed by optical microscopy.The dynam ic compression results demonstrate that AZ31 Mg alloy exhibits obvious yield phe nomena and strain hardening behavior at high strain rates.The basically same cu rvature of stress-strain curves shows a similar strain hardening rate.The dyna mic yield strength changes little,and the peak stress increases with the strain rates.The dynamic hardness test results indicate that the dynamic mechanical p roperties of AZ31 alloy sheet are anisotropic.The dynamic hardness increases sl owly with average strain for the 0° and 45° oriented samples.For the 90° ori e nted sample,dynamic hardness with strain increases rapidly first and then decre ases when the strain is more than 0.14.An examination by optical microscopy aft er high strain rate deformation reveals the occurrence of twinning,and the twin area percentage escalates with the strain rate increasing.