Nanomechanical and EBSD Characterization of Additive Manufactured Mg Alloys

The Solid State Additive Manufacturing (SSAM) process referred to as Additive Friction Stir (AFS) provides a new path for repair, coating, joining and additively manufacturing materials such as magnesium alloys. This additive manufacturing process differs from traditional friction stir welding/processing since metal powder or solid rod is fed through a non-consumable rotating cylindrical tool generating heat and plastically deforming the feedstock material through controlled pressure from the tool as successive layers are built upon a substrate. In this research, the dynamic recrystallization and grain refinement is characterized for the successive layers in as-deposited WE43 samples using Electron Backscattered Diffraction (EBSD). The EBSD results depict grain structures formed by dynamic recrystallization (DRX) with even finer grain structures forming at the layer interfaces. Nanoindentation performed on the deposited WE43 was spatially correlated to scanning electron microscopy – energy dispersive X-ray spectroscopy (SEM-EDX) to provide a relationship of the nanomechanical modulus and hardness to the indent chemical composition.