Study the effect of Bauxite ceramic powder on the fracture mechanics of aluminum alloy using digital image correlation

The modern research and industries have seen great interest in reinforcement of aluminum metal composites, AMMCs by ceramic particles due to their superior properties and applications. Digital image correlation, DIC method has proved its accuracy and effectiveness in tracking of crack initiation, propagation, and plastic deformation ahead the crack tip in fracture mechanics investigations. In this study, DIC was used to detect the surface strain and plastic deformation (necking) during tensile test of AMMCs reinforced using Iraqi natural bauxite ceramic powders (2-6% wt) with particle size of 3.3µm using stir casting method. Also, the mechanical properties and fracture mechanics of AMMCs cast were investigated using extensometer method for comparison with DIC method. The results show maximum values for the ultimate tensile strength, yield strength, and Young’s modulus (E) at 4% bauxite addition while the 6% addition exhibits the composite a nearly brittle behavior. Also, the hardness increases with bauxite increasing from 19.3 HBN for the aluminum matrix to 40.1 HBN for the AMMCs. DIC results could prove its superiority in comparison to the extensometer method as a suitable and very precise contactless method to identify the localized strain at the necking region and the plastic deformation at this region and the distribution of the brittle phases under tensile loading.