ABSTRACT

Understanding and describing plastic deformation in polycrystalline
materials is fundamentally challenging due to the complex atomic
rearrangements that must occur at grain boundaries. Thus, there is a
significant need to develop new techniques to study, correlate, and
describe deformation accommodation at grain boundaries. Due to hexagonal
structure of the hcp materials, these metals exhibit strong anisotropy
mechanical properties, which is more pronounced than for construction
metals with cubic crystal structure. Deformation mechanisms in hcp
metals, dislocation motion on specific slip systems, activation of
twinning, and interaction between them and Grain boundary are not yet
completely understood. On the other hand, understanding of solidification
microstructure evolution in complex hcp structures can help to have a
link between processing routes, microstructures, properties and
performance of these materials.
Within this framework, the work presented in this first year assessment
has two objectives. The first one is to develop a new gradient furnace
for in-situ tomography solidification purpose. The second goal is to
correlate observations of slip transfer with a geometric parameter m’,
which can be used to identify and predict crystallographic arrangements
that are better suited for slip transfer.