environmental stress cracking
The environment stress cracking refers to the failure of metals or polymers in the presence of mechanical stress and specific environmental elements, including chemicals, moisture, or ultraviolet light. Cracks are formed instantaneously and without significant deformation, often at stress levels well below the yield strength of the material.
Key Feature:
- Bimodal Failure: When external stress and environmental exposure interact, only then will failure develop. If such an event were considered purely external, the resulting physical process would not conform to rules governing escape from ductile deformation.
- Cracking Without Yielding: Cracking occurs in an instant with little to no visible plastic deformation; therefore, it serves as a deadly silent threat.
- Material and Chemical Specific: The extent of susceptibility depends on the type of material, along with the specific chemicals or environmental conditions involved.
Environmental stress cracking presents a serious consideration in applications for chemical storage tanks, piping systems, and consumer products. For example, a plastic component under steady tension may crack earlier than would normally be expected in the presence of detergents or solvents. In metals, factors in the external atmosphere or particular industrial chemicals may enhance the rate of crack initiation.