Experimental and Numerical Investigation on Ductile-brittle Fracture Transition in a Magnesium Alloy

Tensile test on smooth and circumferentially notched specimens, systematic observation of fracture surfaces and large deformation finite element analysis were conducted to understand the deformation and failure behavior of a magnesium alloy (AM60). The plastic deformation is considered to be dominated by twining mediated slip. The tensile properties were not sensitive to the strain rates applied (3.3x10~0.1). Corresponding to the same loading level, higher stress triaxiality but lower plastic strain was observed in the specimens with a smaller notch profile radius. Deformation and failure of the magnesium alloy were sensitive to the constraint level and ductile-brittle fracture transition occurred with decreasing the notch profile radius.