ABSTRACT
Nondestructive testing, while of obvious benefit in the industrial environment, is not the only approach. Traditionally, most materials evaluation methods involve the use of test samples cut from the materials or components of interest. Alternatively, representative samples taken from a batch of nominally identical specimens may be subjected to laboratory testing. In some cases, destructive tests are more economical than nondestructive tests because the cost of the destructive test is usually lower. Therefore, for low-cost parts, the sacrifice of a few components can be tolerated. On the other hand, for high-added-value parts, the cost of sacrificing some parts may outweigh the additional cost of nondestructive testing, and even if it does not, the use of representative samples is founded on the uncertain assumption that the remaining samples will behave in the same way. Additionally, in some applications it is necessary to directly test the actual part that will be in service. This chapter also looks at materials characterization as a special case of testing, which, because of its different objective of determining materials properties instead of defect detection and failure, can be distinctly different from nondestructive evaluation.
