Quantitative assessment of preferential fatigue initiation sites in a multi-phase aluminium alloy

Complex multi-phase Al–Sn–Si alloys are commonly employed in the manufacture of small automotive plain bearings. The fundamental fatigue initiation behaviour of this class of alloys is currently not well understood. A range of analytical techniques were applied to investigate preferential initiation site location and to attempt to identify critical microstructural features. It was apparent from experimental studies that points of fatigue crack initiation are associated with the Si secondary phase. Using tessellation approaches and subsequently both adaptive numerical modelling and micro-scale finite element modelling allowed the identification of features affecting the probability that a given Si phase would initiate a fatigue crack.