Effect of constraint on tensile behavior of an AZ91 magnesium alloy

The deformation and failure behaviour of a cast AZ91 alloy was investigated using tensile test on the circumferentially notched tensile specimens with different notch radii. The strain and stress triaxiality corresponding to the failure point were estimated. The fracture surface was observed using scanning electron microscopy (SEM). The results indicated that deformation and failure of the AZ91 magnesium alloy are very sensitive to constraint level (stress triaxiality). The fracture mechanisms changed from typical ductile tearing to quasi cleavage with increasing constraint level. (C) 2004 Elsevier B.V. All rights reserved.