The Significance of Material Ductility to the Reliability and Load Carrying Capacity of Peak Performance Structures.
Final rept. 1 Jan 73-31 May 74,
SYRACUSE UNIV N Y DEPT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCE
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Biaxial ductility test on aluminum 7050 - T73651 and 2014-T6 showed that aluminum alloys follow the predictions of the volume strain fracture criterion, i.e. the fracture ductility decreased monotomically from the uniaxial stress state to plane strain to balanced biaxial condition. No such conclusion was possible for the steels. A miniature bulge test fixture was designed, built and tested following Azrin and Backofen. In comparison to all the ductility test methods studied, the hydraulic bulge test maintains the initial stress state to failure for most materials while necking generally intervenes before fracture for the three biaxial tests. The hydraulic bulge test is, therefore, proposed for use in fracture toughness, ductility, correlation work. Based on the authors proposed correlation between fracture resistance and local fracture strain, a method for analytical predictions of the thickness effect on fracture toughness is presented.
- Metallurgy and Metallography