Label the mean stress and the maximum stress on this fatigue

Label the mean stress and the maximum stress on this fatigue stress graph. Which kind of fracture is associated with the intergranular crack mechanism? ductile brittle either ductile or brittle

Solution

6-b.Brittle-In dealing with brittle fracture, cracks spread very rapidly with little or no plastic deformation. The cracks that propagate in a brittle material will continue to grow and increase in magnitude once they are initiated. Another important mannerism of crack propagation is the way in which the advancing crack travels through the material. A crack that passes through the grains within the material is undergoing transgranular fracture. However, a crack that propagates along the grain boundaries is termed an intergranular fracture