The Use of an Alternative Method for Fracture Toughness Evaluation on Different Materials

摘要

Through this paper an alternative procedure to obtain fracture toughness parameters on blunt-notched samples rather than on standard sharp-notched samples has been applied to several materials which display different fracture behavior. An aluminum alloy, an austempered ductile iron (ADI), and two different polymeric materials, polyamide 6 and poly(methyl methacrylate) (PMMA), were tested. The use of the alternative methodology allows simplification and cost reduction in fracture toughness evaluation. For the aluminum alloy, the fracture parameter obtained by this method was 16 percent lower than that determined using ASTM standard methodology with data scatter similar to that reported in literature. For the ADI, fracture toughness values from blunt-notched samples were close to those obtained using standard test samples, showing low sensitivity to the changes in the crack tip diameter. For polyamide 6, the alternative methodology led to a toughness value within the same range of the values obtained from the traditional technique. In the case of the PMMA, the K_(IC) values obtained from both methods showed good agreement.