Improving the strength-ductility synergy of AZ80 alloy by twinning-dominated deformation combined with interrupted aging

AZ80 alloy is one of the most important commercial Mg alloys. However, its strength is still not high enough for wide applications due mainly to the poor precipitation strengthening effect. In this work, a new processing route, i.e. twinning deformation combined with interrupted aging, is proposed to effectively improve the strength of AZ80 alloy. Microstructural characterization reveals that basal precipitates are formed in the first stage of aging (200 degrees C/10 h), which are re-oriented to be parallel to the prismatic planes by the subsequently applied twinning dominant deformation. New basal precipitates are formed in the second stage of aging (200 degrees C/20 h) and the prismatic ones formed ahead remain stable. Therefore, by applying this new processing route, both prismatic and basal precipitates can be generated in the alpha-Mg matrix, forming a dual-precipitates microstructure. As a consequence, the strength-ductility synergy of the AZ80 alloy is remarkably improved in this work, which is superior to most recently reported AZ80 alloys. The experimental results indicate that this new processing route is practical, effective and economical, which has a great potential for developing low-cost and high-performance Mg alloys.