Browsing by Subject "deposition parameters"
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Item Design of an Empirical Process Model and Algorithm for the Tungsten Inert Gas Wire+Arc Additive Manufacture of Ti-6Al-4V Components(University of Texas at Austin, 2013) Martina, Filomeno; Williams, Stewart W.; Colegrove, PaulIn the wire+arc additive manufacture process parameters can be varied to achieve a wide range of deposit widths, as well as layer heights. Pulsed Tungsten Inert Gas was chosen as the deposition process. A working envelope was developed, which ensures unfeasible parameters combinations are excluded from the algorithm. Thanks to an extensive use of a statistically designed experiment, it was possible to produce process equations through linear regression, for both wall width and layer height. These equations are extremely useful for automating the process and reducing the buy-to-fly ratio. For a given layer height process parameters can be selected to achieve the required layer width while maximising productivity.Item EFFECTS OF DIFFERENT PARAMETERS ON DED HR-1 ON LOW CYCLE FATIGUE, TENSILE STRENGTH, AND MICROSTRUCTURE(University of Texas at Austin, 2023) Lares, J.; Godinez, D.; Arrieta, E.; Medina, F.; Wicker, R.; Gradl, P.; Katsarelis, C.NASA HR1 alloy is an iron-nickel based material designed by NASA and derived from A286 and JBK-75 alloys. At extreme conditions, NASA HR1 possess high strength, high fatigue resistance, and high resistance to corrosion and hydrogen embrittlement. The main applications include structural components and liquid rocket engine nozzles with internal cooling channels. NASA has produced HR1 using vacuum induction melting (VIM), a considerably expensive fabrication method. Aimed to explore other more affordable and accessible manufacturing methods, HR1 specimens were fabricated under different parameters using Laser-Powder Directed Energy Deposition (LP-DED) and were heat treated through stress relief, homogenization, solution treatment and aging. The feasibility of this AM process was investigated by evaluating mechanical and microstructural analysis on specimens. This work finalizes with discussion and remarks on tensile and low-cycle fatigue properties and its relationship with microstructural features.Item Numerical Analysis of Thermal Stress and Deformation in Multi-Layer Laser Metal Deposition Processes(University of Texas at Austin, 2013-08-16) Liu, Heng; Sparks, Todd E.; Liou, Frank W.; Dietrich, David M.Direct metal deposition (DMD) has gained increasing attention in the area of rapid manufacturing and repairing. This process involves extremely high thermal gradients and heat and cooling rate, resulting in residual stresses and distortion. This paper presents a 3D sequentially coupled thermo-mechanical finite element model to predict residual stresses and deformations. The temperature distribution, thermal stress field and geometry deformation across domain are illustrated. The effect of deposition parameters on residual stress and deflections are also explored. A set of validation experiments for mechanical effects were conducted using laser displacement sensor. The comparisons between the simulated and experimental results show good agreement.