Browsing by Subject "temperature gradient"

Now showing 1 - 2 of 2
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    3-Dimensional Finite Element Modeling of Selective Laser Melting Ti-6Al-4V Alloy
    (University of Texas at Austin, 2014) Fu, C.H.; Guo, Y.B.
    Selective laser melting (SLM) is widely used in making three-dimensional functional parts layer by layer. Temperature magnitude and history during SLM directly determine the molten pool dimensions and surface integrity. However, due to the transient nature and small size of the molten pool, the temperature gradient and the molten pool size are very challenging to measure and control. A 3-dimensional finite element simulation model has been developed to simulate multi-layer deposition of Ti-6Al-4V in SLM. A physics-based layer build-up approach coupled with a surface moving heat flux was incorporated into the modeling process. The melting pool shape and dimensions were predicted and experimentally validated. Temperature gradient and thermal history in the multi-layer build-up process was also obtained. Furthermore, the influences of process parameters and materials on the melting process were evaluated.
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    Convection Heat Transfer Coefficients for Laser Powder Bed Fusion
    (University of Texas at Austin, 2018) Masoomi, Mohammad; Soltani-Tehrani, Arash; Shamsaei, Nima; Thompson, Scott M.
    This study investigates the effects of convection heat transfer during the laser-powder bed fusion (L-PBF) additive manufacturing process. For the L-PBF process, parts are fabricated under a purged, inert environment to avoid oxidation. Part of the delivered laser energy is transferred to the process chamber/environment through radiation and convection during fabrication. In this study, customized computational fluid dynamics (CFD) software is used to simulate the L-PBF of a single layer of stainless steel 17-4 PH. Local temperature and temperature gradients, as well as dimensionless numbers descriptive of important thermophysics, are provided in order to quantify local convective heat transfer. The results are used to predict local heat transfer coefficients during the L-PBF additive manufacturing process.