Thermal diffusivity estimation in metallic alloys using a one-dimensional flux-based thermography

This work proposes a simple one-dimensional (1D) thermography technique to estimate a metallic alloy thermal diffusivity by employing a uniform flux-based heating source. A theoretical model is developed and validated to account for the sample dimensions, material thermal properties and the sample initial and boundary conditions. These conditions include the sample initial temperature, the effective convection heat transfer coefficient with the surrounding environment and the uniform heat flux supplied to the sample. The adopted theoretical model is tested against simulated thermal measurements to retrieve a sample unknown boundary conditions along with the material thermal diffusivity of interest following the Nelder-Mead optimization approach, which offers a high flexibility to the proposed technique. This technique is experimentally validated over a tempered aluminum alloy (Al-2024 T4) of relatively high thermal diffusivity and a one-order of magnitude lower thermal diffusivity annealed stainless-steel alloy (SS-304) delivering an uncertainty lower than 2 % in material thermal diffusivity estimation.

Automated summary

This study proposes a simple one-dimensional thermography technique to estimate the thermal diffusivity of metallic alloys. A theoretical model is developed and validated to account for sample dimensions and material properties, and experimental validation is done on tempered aluminum alloy and annealed stainless steel alloy, showing an uncertainty lower than 2% in material thermal diffusivity estimation.