Spatial point pattern methodology for the study of pores 3D patterning in two casting aluminium alloys

Driss El Khoukhi (1) , Nicolas Saintier (1) , Franck Morel , Daniel Bellett , Pierre Osmond , Viet-Duc Le

1 I2M - Institut de Mécanique et d'Ingénierie

Two cast aluminium alloys fabricated by different casting processes (gravity die-casting and lost foam casting) and showing different degrees of porosity were characterized with X-ray Computed tomography. Information concerning the pore distribution inside the investigated materials is obtained in terms of pore size and the pore positions in 3D space. Subsequently, a spatial point pattern analysis is undertaken to investigate the pore distributions. Different methods, including a nearest neighbor analysis, Ripley's K-function and Clark-Evans tests developed for 3D applications, are used to analyse the observed patterns. The results show that the Homogeneous Poisson process, which provides the Complete Spatial Randomness (CSR) is suitable to approximate the spatial distribution of the pores present in the investigated alloys. Synthetic microstructures that mimic key macroscale features of the materials in terms of pore size and the 3D spatial distribution of the pores were generated. These microstructures can be used in the probabilistic modelling of fatigue behavior.

Mots clés: Casting process; X-ray computed tomography; Porosity; Point pattern; Spatial statistics; Ripley's K-function Nearest neighbor function; Poisson process; Fatigue

Domaines: Matériaux

Driss El Khoukhi, Nicolas Saintier, Franck Morel, Daniel Bellett, Pierre Osmond, et al.. Spatial point pattern methodology for the study of pores 3D patterning in two casting aluminium alloys. Materials Characterization, 2021, 177, pp.111165. ⟨10.1016/j.matchar.2021.111165⟩. ⟨hal-03472740⟩