Abstract Scope |
Additive manufacturing processes of metallic materials involve complex physics and often the generation and/or retention of various defects (e.g., pores, keyholing). Defects are perceived as undesirable as they significantly affect key properties. Thus, in-situ monitoring and/or post-deposition processes are typically undertaken to avoid their formation or eliminate them. However, these otherwise bad actors can act as 'informants', revealing information about the temperature fluctuations, phase transformations, and stresses that occur, both locally and in the part as a whole. Microstructural, crystallographic, compositional, and morphological analysis of defects in electron beam powder bed printed Ti-6Al-4V parts, as well as knowledge of their mechanisms of formation, among other aspects, has been used to reveal key information about the physical mechanisms undergone by the material during the build process, including the relationship between local thermal stresses and cyclic phase transformations, melt pool fluid flow, and grain growth and formation. |