Browsing by Subject "foils"
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Item Characterization of two distinct, simultaneous hot electron beams in intense laser-solid interactions(2009-11) Cho, B. I.; Osterholz, J.; Bernstein, A. C.; Dyer, G. M.; Karmakar, A.; Pukhov, A.; Ditmire, T.; Cho, B. I.; Osterholz, J.; Bernstein, A. C.; Dyer, G. M.; Ditmire, T.The transport of energetic electron beams generated from aluminum foils irradiated by ultraintense laser pulses has been studied by imaging coherent transition radiation from the rear side of the target. Two distinct beams of MeV electrons are emitted from the target rear side at the same time. This measurement indicates that two different mechanisms, namely resonance absorption and jxB heating, accelerate the electrons at the targets front side and drive them to different directions, with different temperatures. This interpretation is consistent with 3D-particle-in-cell simulations.Item Construction of Metallic Glass Structures by Laser-Foil-Printing Technology(University of Texas at Austin, 2017) Shen, Yiju; Li, Yingqi; Tsai, Hai-LungMetallic glasses (MGs) have superior mechanical properties such as high tensile strength, hardness, and corrosion resistance, as compared to crystalline metals. Although newly developed MGs have significantly reduced critical cooling rates down to 10 K/s, products of MGs are still limited to simple geometries such as foils/plates or rods with thin section-thickness which is mainly caused by the decrease of thermal conductivities of the new MGs. Recently, we developed a new Laser-foil-printing (LFP) additive manufacturing technology which welds foils, layer by layer, to construct desired 3D structures. With the LFP and Zr-based amorphous foils, 3D, large amorphous structures with complex geometry have been successfully manufactured. To better understand the evolution of crystalline phase, we integrate the finite element based heat transfer model and classic nucleation theory (CNT) based crystal nucleation/growth model. The model was used to demonstrate the evolution of crystal phase as a function of time during laser welding at different locations including the fusion zone (FZ) and heat-affected zone (HAZ). The model is also compared favorably with the experiment results. The reported susceptibility to crystallization in HAZ were discussed and explained.