Materials testing is the evaluation of components or systems in a non-destructive fashion to detect flaws, contamination, inconsistency in material or other physical parameters. A materials test will use methods which allow for in-depth analysis without destroying the sample or, if it is a product, rendering it useless.
An ultrasonic flaw detector will emit high frequency sound waves which, when they bounce off of flaws, produce echo patterns that can reveal cracking, excess porosity and other structural anomalies. Thickness gauges, on the other hand, determine the thickness of an object by sending ultrasonic waves into its center, recording the speed of sound through the test sample and calculating thickness from the data.
Laser methods can assess the makeup of an object as well; a laser micrometer reveals how brittle, elastic, deformed or soft something is, as well as its temperature. Ionographs discover ionic contamination in electronic components like printed circuit boards. Other technologies, like roughness testers and coordinate measuring machines, use styluses or probes to gather data on the consistency of the exterior and its exact spatial measurements respectively.
XRF testing involves exposing a sample to x-rays, and then measuring the resulting flourescence.