Executive Summary : | Magnesium (Mg) alloys are promising for lightweight transport and structural applications in the automobile and aerospace industries. However, their applications are limited due to high directional anisotropy and low crystal plasticity. Mg alloys containing yttrium and other rare earth elements show improved room temperature ductility through activation of c+a non basal dislocations, formation of double twins, and weakened basal texture. However, rare earth Mg alloys are difficult to process, commercially unattractive, and not compatible for recycling processes. The primary interest of this proposal is to investigate the edge and screw dislocations - twin boundary interaction mechanisms in rare earth free magnesium alloys Mg-XBi and Mg-XBi-XSn through transmission electron microscope studies. Understanding these interaction mechanisms is crucial for improving the mechanical properties of magnesium alloys. Previous experimental studies have studied basal a and basal dissociated c and c+a dislocations interaction mechanisms, but c and c+a dislocations (lying on non-basal planes) interaction with twin boundaries and dislocation-twin interaction mechanisms when the burgers vectors of edge and screw dislocations exhibit different orientations with twin boundaries have not been studied experimentally to date. |