About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
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Symposium
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Additive Manufacturing: Advanced Characterization with Synchrotron, Neutron, and In Situ Laboratory-scale Techniques II
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Presentation Title |
In Situ X-ray Diffraction and Visualization of Laser Melting and Subsequent Phase Evolution |
Author(s) |
Anthony D. Rollett |
On-Site Speaker (Planned) |
Anthony D. Rollett |
Abstract Scope |
In situ x-ray experiments at modern light sources have provided many insights into materials aspects of laser-based additive manufacturing. Visualization of the melting process has demonstrated the importance of metal vaporization for, e.g., driving keyhole development, porosity formation, spatter, hot cracking and absorptivity. Related to the scientific impact has been the importance of the new understanding on process control: the laser light intensity is directly related to spot size, which then controls the intensity of keyholing. Absorptivity directly influences the extent of melting, which in turn affects melt pool overlap and whether or not lack of fusion porosity occurs. Post-solidification, in situ diffraction experiments reveal phase evolution. Stainless steel (316) is found to solidify as ferrite before transforming (partially) to austenite [CHECK J’s paper]. Alloy 718 precipitates carbides and Laves phase but not other commonly observed phases. At high enough cooling rates, Ti-6Al-4V transforms martensitically. |
Proceedings Inclusion? |
Planned: |
Keywords |
Additive Manufacturing, Solidification, Phase Transformations |