|About this Abstract
||MS&T21: Materials Science & Technology
||Nucleation of Solid-State Phase Transformations
||Observing the Solid-state Processes under Additive Manufacturing Conditions Inside the TEM
||Sriram Vijayan, Meiyue Shao, Avantika Gupta, Rohan Casukhela, Joerg Jinschek
|On-Site Speaker (Planned)
Rapid thermal cycling and steep thermal gradients are the dominant process conditions during metal based additive manufacturing (AM) techniques such as powder bed fusion. These process conditions cause reduced partitioning of solute and thereby lead to the formation of metastable microstructures with an anisotropic, columnar morphology. To fabricate AM components with equiaxed microstructures, a careful understanding of AM process conditions is still needed. In this study, we describe the use of a MEMS-based heating stage to simulate ‘AM like’ processes inside a transmission electron microscope (TEM). This modified MEMS device enables us to study the microstructural response of the material under the combined influence of large thermal gradients (106 K/m) and rapid thermal cycling. We expose TEM lamellae, obtained from AM builds, to ‘AM like’ conditions in-situ to understand fundamental processes that contribute to the microstructural evolution of AM Ti-6Al-4V and Inconel 738 during the AM build process.