Abstract
Magnesium alloy AZ91 (Mg-9.2Al-0.7Zn-0.26Mn) was prepared by chill casting technology. Samples were subjected to solution treating followed by step-by-step isochronal annealing at temperatures from 300 to 723 K.
Microstructure changes due to annealing of the samples were studied by means of electrical resistivity and Vickers hardness measurements. Pronounced resistivity and hardness changes were observed between 500 and 650 K.
Light microscopy studies were performed in order to identify the development of the microstructure. It was found that the resistivity and hardness changes are due to continuous and discontinuous precipitation processes in the alloy.
Measurements of the electrical resistivity could be pointed out as an effective tool for study of the samples thermal history.