Investigation of Non-Basal Slip in Mg-1Y (wt%) using HR-EBSD and Digital Image Correlation (DIC)

Magnesium alloys are lightweight materials with potential applications in aerospace and the automotive industries; however, the challenge remains overcoming Magnesium’s low strength and low formability. By alloying with small amounts of rare earth metals like Yttrium, Magnesium alloys have shown an increase in strength and in ductility. Researchers have proposed that the activation of non-basal slip, with a higher CRSS than basal slip and prismatic slip, is responsible for cross slip of dislocations on the <c+a> planes. It is suggested that the segregation of Yttrium at the grain boundaries must lower the activation energy of non-basal slip, making the higher CRSS a smaller barrier to overcome for dislocation transmission across grain boundaries. Using In-Situ tensile testing at strain rates of 10^-3 coupled with High Resolution EBSD and Digital Image Correlation, this works investigates the origin of non-basal slip in Mg-1Y (wt%) and quantifies the complex stress state located in the interior grain vs grain boundaries. The use of the EBSD helps characterize the role crystal orientation plays in the deformation mechanism of non-basal cross slip.