Texture and Microstructure Developments during Friction Stir Processing of Magnesium Alloy AZ31

摘要

As the need for more fuel-efficient vehicles having lesser carbon emissions is growing, the applicability of light weight metal such as magnesium having low density and high ratio of strength to weight have gained momentum to replace aluminum and steel in aerospace and automobile industry [1]. However, poor formability and low ductility of magnesium alloys due to inherent hexagonal close packed (HCP) structure and low hardness, strength and wear resistance posses' practical problems in its applicability at room temperature. Since, limited slip systems are available at room temperature; the deformation of magnesium alloy is complicated as compared to FCC metal alloys and highly texture dependent. There is considerable difference in the critical resolved shear stress of basal slip system and other slip systems ( prismatic and pyramidal) at room temperature and hence imparts high anisotropy in the mechanical properties of Magnesium. Basal slip system {0 0 0 2} <1 1 2 0> can be easily activated in magnesium alloys but it alone can't accommodate for the general plastic deformation and other non basal slip systems are needed to improve room temperature formability [2], Microstructure and texture modification can be done for activating non-basal slip systems and hence suitable thermo-mechanical processing needs to be formulated to accomplish this goal.