Effect of equal channel angular pressing on magnesium alloys − A review

Abstract

Magnesium (Mg) alloys own excellent properties that includes better castability, low density and great specific strength. Mg and its alloys are easily available and economical. Necessity of Mg and its alloys for manufacturing and engineering purposes has increased, predominantly in the area of aircraft and automobile applications. The known limitation of magnesium is its poor formability at room temperature, with inadequate slip systems due to hexagonal closed packed construction of magnesium. Formability of magnesium alloys will be enhanced at room temperature by grain structure refinement which improves ductility with grain refined structure. Severe plastic deformation (SPD) procedure induces extreme strain within the sample to produce ultrafine grained structure. Additionally, few shortcomings of magnesium is increased wear mass loss and corrosion rate obstructing the use of Mg and its alloys in several industrial appliances. Wear resistance and corrosion behaviour can be enhanced by SPD thereby increasing the requirement of magnesium alloys for engineering applications. Among SPD, equal channel angular pressing (ECAP) is an efficient approach to develop and vary the mechanical and microstructural properties as per the need. In ECAP approach, the workpiece undergoes shear deformation and large strains are induced in the workpiece with no variation in cross sectional aspect of the workpiece. Microstructure plays a very important role in achieving the required mechanical properties. ECAP process creates ultrafine-grained microstructure with different number of ECAP passes with varying temperatures inducing high strain rate.