ABSTRACT
In the aerospace industry, due to its basic requirement of light-weight metals and alloys, Mg has attracted large attention. The density of Mg (1.74 gm/cm3) is only two-third that of aluminum (2.70 gm/cm3) and one quarter that of steel (7.85 gm/cm3). These alloys are even popular in other sectors like automobile, biomedical, architecture and electronic industries (1). In order to produce components by various manufacturing processes, the material should possess good ductility. Various microstructural aspects of material play a very important role in influencing flow properties (2). Mg has excellent machining characteristics; it is estimated that Mg alloys may be safely machined at about ten times the rate possible for steel and twice that possible for aluminum. But, from production point of view, there is a need for good forming properties in a material. If the formability of Mg-alloys is compared to that of other materials like steel and aluminum, it has limitations. It has been attributed to its Hexagonal Close Packed (HCP) type of crystal structure. It has only three slip systems available for deformation i.e. basal, prismatic and pyramidal and, at room temperature (RT); only two of them are active. The third slip system becomes active only at elevated temperature. So, it is necessary to carry out high temperature deformation of Mg to activate other slip systems and mechanisms for deformation. However, high temperature deformation may affect some of the mechanical and metallurgical properties unfavorably (3).
