What is the term for an interruption in the physical structure of a part that produces a visual testing indication?

The term "discontinuity" refers specifically to an interruption in the physical structure of a material or component, which is relevant in the context of visual testing. In this field, a discontinuity can manifest as cracks, voids, or any other flaws that disrupt the continuity of the material's surface. Visual testing aims to identify these discontinuities through various methods of inspection, as they can impact the integrity and performance of the part.

Discontinuities can be critical in determining the quality and reliability of a component. Recognizing and classifying these interruptions helps engineers and inspectors make informed decisions regarding repairs, further testing, or replacement of materials.

While the other terms, such as defect, indication, and deformation, are related to issues in materials, they do not precisely capture the specific meaning of an interruption in structural continuity as seen with "discontinuity." A defect might imply a problem with the functionality, an indication refers to a sign of possible discontinuities seen during testing, and deformation pertains to a change in shape rather than a break in continuity. Thus, "discontinuity" is the most accurate term to describe this phenomenon in visual testing.