Failure Mechanisms

· Rupture of a ductile sample involves extensive plastic deformation in the neck region with a final reduction of the neck area to zero.
· In a single crystal sample, the process involves dislocation induced slip on two intersecting slip planes. The sample shape changes are shown in the top diagram.
· In a polycrystalline sample, neck area reduction continues until the zero area condition is reached. Pure materials can exhibit this behavior at high homologous temperatures.

From: Courtney, "Mechanical Behavior of Materials," McGraw Hill (1990)