Grain size effect on deformation mechanisms in Mg-3Gd

Abstract

Mg-3Gd (wt. %) samples were prepared by accumulative roll-bonding (ARB) and subsequent annealing to produce samples with average grain sizes in a wide range from 3.3 μm to 45.1 μm. These samples were tensile tested at room temperature. Dislocation structures and deformation twins in the tested tensile samples were characterized by transmission electron microscopy. Dislocations with different types of Burgers vector were identified based on two-beam diffraction contrast experiments. The results revealed that deformation twins and dislocations are dominant in coarse-grained samples while and dislocations characterize the fine grain deformation structure. The transition of deformation mechanisms and its implications for microstructural design and property optimization are discussed.