|About this Abstract
||2021 TMS Annual Meeting & Exhibition
||Additive Manufacturing of Metals: Applications of Solidification Fundamentals
||Characterization of Material Solidification Behaviors in Laser Powder Bed Fusion Using Operando Synchrotron X-ray Imaging
||Tao Sun, Lianyi Chen
|On-Site Speaker (Planned)
In laser powder bed fusion (LPBF), a high-power laser scans across the powder layer with high velocities. This creates extreme thermal conditions (i.e. high temperature, fast cooling rate) and complex multi-phase dynamics (i.e. strong melt flow, high recoil and vapor dynamic pressures). As a result, LPBF-processed materials possess unique microstructures and thereby different mechanical properties than casted or wrought samples. Understanding the solidification behaviors of materials in LPBF requires the quantitative characterization of the solidification velocity and thermal gradient. At the Advanced Photon Source, we applied high-speed x-ray imaging to probe the dynamics of the keyhole and melt pool with micrometer spatial resolution and single x-ray pulse temporal resolution (i.e. ~100 ps). The result reveals that the solidification line (i.e. rear melt pool boundary) exhibits interesting morphological oscillation, driven by the keyhole fluctuation and melt flow, which leads to different solidification velocities at different depth of the melt pool.
||Additive Manufacturing, Characterization, Solidification