Analysis of Fatigue Crack Growth Resistance of Aluminum Matrix Composites

Authors

Calderón, Hermes E.

Suárez, Oscar Marcelo

Abstract

This work analyzes fatigue resistance of aluminum matrix composites with the support of robust statistics. The experimental samples studied were aluminum-based composites with a matrix containing Al, Cu and Mg and reinforced with diboride particles fabricated via both gravity and centrifugal casting. The variation in fatigue strength due to boron addition (forming diboride particles) was assessed via a comparison of the Paris equation exponent calculated for each composition as the slope of the da/dN vs ΔK curve plotted on a log-log scale. This approach, combined with the implementation of Kujawsky’s crack driving force parameter and the application of robust statistics, allowed identifying variations in the crack growth behavior due to heterogeneities in the microstructure. The results showed that samples obtained via centrifugal casting have a higher fatigue resistance than those obtained via gravity casting. In addition, the analysis demonstrated how crack growth resistance decreased by increasing amounts of reinforcing particles in the material. The use of a robust statistics analysis was fundamental to avoid rejecting data from samples exhibiting variations in the crack growth curve.