Crack Propagation Behavior in Pure-aluminum

摘要

The behavior of fatigue crack growth in pure aluminum during cyclic torsional tests was observed using pre-cracked specimen. The crack propagation tests were carried out by the cyclic torsion with a static axial stress. In the case that high level of static tension was applied with cyclic torsion, the fatigue crack grew by shear mode. Also, fatigue crack pass made almost straight line. However, in the case that only cyclic torsiond stress was applied, branching of the crack was observed and fatigue crack propagation rate was lower than that of former case. It is found that the crack tip opening by the static tension affected to the crack growth behavior under cyclic torsion in pure aluminum. In addition, the cyclic torsion tests of pre-torsion specimen were performed. From these tests, it was found that the distortional crystal orientation and the strain hardening affected the crack growth behavior.