In eddy current testing, what is the term for the effect of the material's magnetic domain response to an external magnetic field?

The correct term for the effect of the material's magnetic domain response to an external magnetic field is permeability. Permeability is a measure of how easily a material can support the formation of a magnetic field within itself. This property is essential in eddy current testing because different materials exhibit varying levels of permeability, affecting the way eddy currents are generated and behave.

In eddy current testing, the interaction between the magnetic fields created by the coils and the material being tested relies heavily on the permeability of that material. Materials with high permeability will allow magnetic lines of force to pass through them more easily, which leads to a more significant induction of eddy currents. Conversely, materials with low permeability will exhibit reduced eddy current generation.

Understanding permeability is crucial for interpreting the results of eddy current tests, as it impacts the detectable responses to flaws or material discontinuities. Therefore, the knowledge of permeability helps technicians to assess the material properties and potential defects effectively during inspections.