SINOPSIS

An annular thermal-wave diffusing measurement method for local thermal diffusivity evaluation is reported. The local thermal diffusivity is calculated by fitting all specific theoretical equation parameters estimated from the original temperature evolutions of different ring areas of the sample. The proper time and space range for thermal diffusivity calculation is determined using the principal component analysis (PCA). Compared with the conventional method, that requires the calculation area large enough to perform a complete and reliable Gaussian temperature fitting, the main advantage of this method is that the thermal diffusivity of local area in the whole mechanical structure can be evaluated just by extracting the temperature evolutions close to the heat source center. A measurement system is established with a pulsed Gaussian beam heating the sample surface and an IR camera detecting the temperature distribution. The measured radial thermal diffusivity of local area near the center of samples prepared from both Ti and Ni is in good agreement with the reference data with a 1.3% error bound at maximum.