Abstract
The influences of Fe and Fe+Mn contents were studied by a double torsion bending test. The fracture toughness of as cast and aged alloys is unsusceptible to Fe concentration less than 0.57wt%. When the Fe content is increased up to 1wt%, the fracture toughness lowers by about 20%. Although increase in Fe+Mn content from 0.32 to 1.67wt% has little effect on the fracture toughness, the alloy containing Fe 1wt% and Mn 0.71wt% has improved fracture toughness.
