On the origin of deformation mechanisms in a heterostructured aluminum alloy via slip trace and lattice rotation analyses

In this study the micro-deformation mechanisms in an Al–Si cast alloy under stepwise compressive loading up to a cumulated plastic strain of 9.7% are examined via detailed EBSD and slip trace analyses. The presence of heterogeneous microstructural features in the alloy like eutectic structure and second-phase particles significantly affects slip trace characteristics. Four types of slip traces (namely, bowed, ‘C’-type curved, ‘S’-type curved, and flat slip traces) present in primary α-Al grains are identified, which unveil the nature of dislocation motion in the alloy and reflect the extent of deformation difficulty associated with α-Al grain orientations and eutectic Si particles. Crystallographic factors like lattice rotations, misorientation angles, active slip systems, and Schmid factors are jointly analyzed for the first time to understand the deformation behavior of the heterogeneous alloy.