Non-destructive techniques for microstructural and structural characterisation

The functional quality of a material or a component is influenced by (i) microstructure (ii) flaws (physical discontinuities like cracks, pores, delaminations etc.), and (iii) the presence of stress. Non-destructive evaluation (NDE) techniques are used to control and enhance the quality at various stages of the life cycle of a material or component. In this paper, various NDE techniques are discussed. The techniques mainly discussed are ultrasonics, radiography, X-ray techniques, and acoustic emission. The principles, procedures, advantages, and limitations of each technique, as well as applications in various materials are considered.