Towards non-destructive prediction of porosity-induced mechanical property variations in L-PBF AlSi10Mg via pulsed laser thermography

Additive manufacturing of aluminium alloys by Laser Powder Bed Fusion (L-PBF) enables the fabrication of lightweight and highly integrated components. However, residual porosity still represents a critical limitation for structural applications. Internal voids affect stiffness, strength, and fatigue behaviour, and simultaneously modify the thermal transport properties of the material. This work investigates the use of pulsed laser thermography as a quantitative non-destructive approach to relate porosity to variations in mechanical properties in additively manufactured AlSi10Mg. The study is based on bi-layer specimens composed of a nearly dense surface thin layer and a porous substrate, obtained by systematically varying the hatch spacing during L-PBF. A pulsed laser spot thermography setup in reflection mode is employed to record the transient thermal response. Inverse analysis is used to estimate the in-depth thermal diffusivity of the surface layer and the thermal reflection coefficient at the coating– substrate interface. The results show that the reconstructed thermal parameters, particularly the substrate effusivity, exhibit a clear dependence on porosity. By exploiting established relationships between porosity and mechanical properties for AlSi10Mg, the thermographically estimated effusivity enables a non-destructive prediction of porosity-induced variations in mechanical performance. The proposed methodology represents a step towards fast and scalable NDT-based assessment of additively manufactured aluminium components.