Strength-ductility synergy in a wrought AZ80 magnesium alloy by microstructure engineering

The present investigation is conducted on microstructure engineering of a Mg-8Al-0.5Zn (AZ80) alloy by different processing routes including conventional aging, cold rolling followed by aging, and aging followed by warm and hot rolling in order to find a strength and ductility synergy. Aging at 175 degrees C followed by hot rolling at 200 degrees C is suggested to obtain remarkable mechanical properties with a strength of-450 MPa together with an acceptable total elongation of-8%. This procedure decorates a bimodal microstructure containing a low-volume fraction of discontinuous precipitates at the grain boundaries and a high-volume fraction of fine continuous precipitates in grain interiors. Microstructural analyses and a microstructure-based strength calculation confirm that the recommended thermomechanical treatment leads to bimodal structure and grain boundaries strength-ening together with increasing precipitation strengthening significantly by reducing the size of CP and increasing CP/DP. Achieving superior mechanical properties without adding alloying elements for strengthening is the main advantage of the proposed method. It is suggested that aging followed by hot rolling plays a pivotal role in engineering the microstructure to improve the mechanical properties of AZ80 alloy which is applicable to other age-hardenable magnesium alloys.