**1. Introduction**

Wrought magnesium alloys are one of the most promising lightweight materials of special interests in structural applications due to their homogeneous microstructure and improved mechanical properties compared to as-cast Mg alloys [1]. Mg alloys are one of the most reactive metals that have poor corrosion resistance and low mechanical properties, which limit its applications in industries. Therefore

enhancement of mechanical properties and corrosion resistance has led to greater interest in magnesium alloys because of its special applications [2–4]. Presently much effort is required for preparation of magnesium alloys with a grain size lower than 1 μm, i.e. ultrafine-grained (UFG) materials to improve the strength and corrosion resistance of Mg alloys, many researchers worked and finally developed a severe plastic deformation (SPD) process which greatly contributes towards grain refinement and distribution of secondary phases to enhance mechanical and corrosion properties [5]. However, in SPD, ECAP is most developed and frequently used metalworking technique for significant materials hardening due to increasing dislocation density and considerable grain size reduction to sub-micro-level [6]. Finally, ultrafine grain structure and uniformly distributed secondary phase particles increase re-passivation tendency, which exhibits the improved mechanical properties and corrosion resistance. The ECAP process was planned with two equal channels: traversing at particular angles called the die channel angle (*ϕ*) and the corner angle (*ψ*) subtended at the channels' intersection. In this work, the effect of ECAP die channel angles and processing temperature on microstructures, mechanical properties and corrosion resistance of ECAPed AZ80/91 Mg alloys were investigated.
