Crack Tip Shielding in 2090 Al-Li Alloy
Thermal dependency of fracture toughness as a function of normal cracking and cold pre-stressing (CPS) conditions at the 173 K is studied in 2090 Al-Li alloy. It was found that fracture toughness increases with decreasing temperature for L-T orientation. This behavior is attributed to the increase of delamination cracking associated with transition from localized to homogeneous plastic deformation. CPS effects improve fracture resistance at temperature above 200 K. This behavior relates mainly to the influences of delamination cracking and residual stresses. A simple model is suggested in order to evaluate the contribution of these two sources to the global toughness value.
KeywordsResidual Stress Fracture Toughness Stable Crack Growth Acoustic Emission Technique Plain Strain Condition
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