Role of different material processing methods on the fatigue behavior of an AZ31 magnesium alloy

The influence of extrusion, plate rolling, and sheet rolling on the fatigue life of an AZ31 magnesium alloy is investigated with a microstructure-sensitive fatigue model that comprises both crack incubation and growth stages. The model describes the effect of primary processing on the microstructure by incorporating specific mechanical properties and microstructural attributes such as grain and inclusion sizes. As such, the fatigue model successfully captured the experimentally observed differences in fatigue lifetimes of the Mg alloy due to the induced in-plane constraint effects resulting from different material processing methods. Quantitative prediction of cumulative damage due to cyclic loading and its comparison with experimental data is described in detail.

► Different active deformation mechanisms resulting from various processing methods were observed.
► SEM revealed that intermetallic particles initiated fatigue cracks in all three materials.
► The MSF model captured the effect of microstructural and/or material differences.
► MSF provides a path for exploring how changes to various mechanisms impacts fatigue performance.
► Yield/ultimate strength, particle, and grain sizes affect significantly fatigue life.