Abstract
Pure aluminum is highly ductile and thus fracture occurs by way of large scale yielding. The application of the linear elastic fracture criterion may be doubtful, since it was difficult to separate between stable and unstable propagation of crack in conventional R curve approach. We have measured the thickness dependence of the fracture mode of compact tension specimens, and determined the critical value of the J integral as 18±3 kJ/m^2. This value may be the plane strain fracture toughness; however, the physical meaning of this value is not certain in some respects.
