Compression deformation behavior of AZ91D magnesium alloy at elevated temperature

The compression tests of AZ91D magnesium alloy at elevated temperature were carried out on Instron-5500 at strain rates ranging from 0.005 to 1 s-1 and deformation temperate between 250 and 350 ℃.The true stress—strain curves were obtained and the influences of deformation temperature and strain rate on the curves were analyzed.The constitutive equation and some constants of AZ91D magnesium alloy during compression deformation were gained.The results show that during the compression,the flow stress of AZ91D magnesium alloy decreases with increasing deformation temperature whereas it increase with increasing strain rates.The flow stress of AZ91D magnesium alloy at elevated temperature can be described with the hyperbolic sine function,and the hyperbolic sine value of flow stress will increase linely with increasing natural logarithm of Zener-Hollomon parameter.The strain rate sensitivity index(m) of AZ91D magnesium alloy is equal to 0.14.