In steel hardening processes, laser treatments and wear or machining of ceramics, the microstructural variations of the material are combined with variations of the thermal properties and therefore become detectable by non-destructive photothermal methods. This paper presents the theoretical basis of a parameter profile reconstruction, based on photothermally measured data. It compares numerical approach using the finite difference method with analytical solution, derived directly from the thermal diffusion equation. Both models are applied to photothermal measurements, leading to depth profiles of steel hardness, which are compared with data, destructively obtained from the same samples using Vickers indentation techniques.
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