Nondestructive techniques have potential for characterization of material properties either in situ or on test pieces. The approach is based on the measurement of some physical characteristics of the material under the effect of variations in microstructure and/or stress state. Typical applications include measuring various parameters such as elastic strains dependent upon interplanar spacing of the crystallographic planes by x-ray diffraction, or velocity/attenuation of ultrasonic waves based on the elasto-acoustic effect, or magnetic properties from the hysteresis curves of ferromagnetic materials. To prove the achievement of the design requirements in the heat-treated components, determining the microstructure in a reliable, rapid and cost-effective way is important for heat treatment industry. The aim of this paper is to review research studies on microstructure characterization of heat-treated components via non-destructive techniques.
Prof.Dr. C. Hakan Gür received his BSc, MSc and PhD (1995) degrees from the Department of Metallurgical Engineering of Middle East Technical University (METU, Ankara). He performed research studies at BAM-Berlin between 1991 and 1993. He is the editor of the Handbook of Thermal Process Modeling of Steels (2009 CRC-Press). In 2010, Prof. Gür received the Fellowship Award of the International Federation of Heat Treatment and Surface Engineering. He is currently the chair of the Department of Metallurgical and Materials Engineering (since 2012), and also the head of the Welding Technology and Non-destructive Testing Center (since 2007) at METU. His main research topics include non-destructive characterization of materials, non-destructive testing, heat treatment, and residual stress. He is the author of about 60 journal articles and 140 conference articles.