Lecture1, Next Generation Biomedical Implants Using Additive Manufacturing of Complex, Cellular and Functional Mesh Arrays(24, May 2010, 14:00-16:00)
Lecutre2, Introduction to Additive Manufacturing Concepts– Comparison of Ti-6Al-4V Wrought and Cast Products with Electron Beam Melt Products(28, May, 2010, 14:00-15:30, )
This review summarizes friction-stir welding (FSW) research at the University of Texas at El Paso (UTEP) over a period of a decade and a half, involving 18 different same materials FSW reference systems, and the FSW of 25 different, dissimilar materials systems. The FSW of dissimilar materials systems is distinguished from same materials systems FSW by the formation of complex, intercalated vortex and related flow patterns. These intercalated, lamellar-like patterns represent solid-state flow by dynamic recrystallization (DRX) which facilitates unrecrystallized, block flow in the DRX regime. Residual microindentation hardness or other hardness measured across the weld face provides comparative performance signatures for the same material FSW systems in contrast to the dissimilar FSW systems. Hardness fluctuations or complex spikes occurring in the dissimilar systems are skewed from the weld centerline and are shifted when the tool rotation direction changes or the advancing side is reversed.
Lecture 3, A Review of UTEP Friction-Stir Welding Research on Dissimilar Metal & Alloy Systems (2 hrs.). (28, May, 14:00-15:30)
This review summarizes friction-stir welding (FSW) research at the University of Texas at El Paso (UTEP) over a period of a decade and a half, involving 18 different same materials FSW reference systems, and the FSW of 25 different, dissimilar materials systems. The FSW of dissimilar materials systems is distinguished from same materials systems FSW by the formation of complex, intercalated vortex and related flow patterns. These intercalated, lamellar-like patterns represent solid-state flow by dynamic recrystallization (DRX) which facilitates unrecrystallized, block flow in the DRX regime. Residual microindentation hardness or other hardness measured across the weld face provides comparative performance signatures for the same material FSW systems in contrast to the dissimilar FSW systems. Hardness fluctuations or complex spikes occurring in the dissimilar systems are skewed from the weld centerline and are shifted when the tool rotation direction changes or the advancing side is reversed.
Lecture 4, Characterization of Ti-6Al-4V Cellular Foams Fabricated by Additive Manufacturing Using Electron Beam Melting (31, May, 14:00-15:30)
Ti-6Al-4V open cellular foams were fabricated by additive manufacturing using electron beam melting (EBM). Foam models were developed from CT-scans of aluminum open cellular foams and embedded in CAD for EBM. These foams were fabricated with solid cell structures as well as open (or hollow) cell structures and exhibit tailorable stiffness and strength. The strength in proportion to the measured microindentation hardness is as much as 40% higher for hollow or open cell (ligament) structures in contrast to solid, fully dense EBM fabricated components. Plots of relative stiffness versus relative density were in good agreement with the Gibson-Ashby model for open cellular materials. Stiffness or Young’s modulus values measured using a resonant frequency – damping analysis technique were found to vary inversely with porosity especially for solid ligament, open cellular structure foams. These foams exhibit the potential for novel biomedical, aeronautics, and automotive applications.
Lecture 5, Materials Characterization Applied to Nanoparticulate Environmental Pollutants(2, June, 14:00-15:30)
In this study, Ti-6Al-4V powder (~30 μm mean diameter) was used to build a variety of fully dense prototypes as well as complex, structural-geometrical mesh prototypes and full density to-graded density monolithic prototypes by EBM. The mesh arrays, in particular, can have stress-directed geometrical structures which, together with dimensional variations, can produce very strong, light-weight aeronautical or aerospace components and prototypes superior to metal foams. In addition, because of the electron beam rastering speeds and configurations, the microstructures and related mechanical properties of layered manufactured prototypes can be altered or graded.
Lecture 6, Characterization of Titanium Aluminide Alloy Components Fabricated by Additive Manufacturing Using Electron Beam Melting: Aerospace and Automotive High Temperature Applications. (8, June, 14:00-15:30)
Intermetallic, γ-TiAl, equiaxed, small-grain (~2μm) structures with lamellar γ/α2-Ti3Al colonies with average spacing of 0.6 μm have been fabricated by additive manufacturing (AM) using electron beam melting (EBM) of precursor, atomized powder. The residual microindentation (Vickers) hardness (HV) averaged 4.1 GPa corresponding to a nominal yield strength of ~1.4 GPa (~HV/3), and a specific yield strength of 0.37 GPa cm3/g (for a density of 3.76 g/cm3) in contrast to 0.27 GPa cm3/g for EBM-fabricated Ti-6Al-4V components. These results demonstrate the potential to fabricate near net shape and complex titanium aluminide products directly using EBM technology in important aerospace and automotive applications.
Lecture 7, DRX: The Dynamic Deformation Regime (10, June, 14:00-15:30)
Lecture 8, Comparison of Microstructures and Mechanical Properties for Solid and Mesh Cobalt-Base Alloy Prototypes Fabricated by Electron Beam Melting. (11, June, 14:00-15:30)
The microstructures and mechanical behavior of simple, as-fabricated, solid geometries (with a density of 8.4 g/cm3), as-fabricated and fabricated and annealed femoral (knee) prototypes, and reticulated mesh components (with a density of 1.5 g/cm3) all produced by additive manufacturing (AM) using electron beam melting (EBM) of Co-26Cr-6Mo-0.2C powder are examined and compared in this study. Microstructures and microstructural issues are examined by optical metallography, SEM, TEM, EDS, and XRD while mechanical properties included selective specimen tensile testing and Vickers microindentation (HV) and Rockwell C-scale (HRC) hardness measurements. Orthogonal (X-Y) melt scanning of the electron beam during AM produced unique, orthogonal and related Cr23C6 carbide (precipitate) arrays with dimensions of ~2 mm in the build plane perpendicular to the build direction, while connected carbide columns were formed in the vertical plane, parallel to the build direction, with microindentation hardnesses ranging from 4.4 GPa to 5.9 GPa; corresponding to a yield stress and UTS of 0.51 GPa and 1.45 GPa with elongations ranging from 1.9% to 5.3%. Annealing produced an equiaxed fcc grain structure with some grain boundary carbides, frequent annealing twins, and often a high density of intrinsic {111} stacking faults within the grains. The reticulated mesh strut microstructure consisted of dense carbide arrays producing a microindentation hardness of 7.7 GPa or roughly 70% higher than the fully dense components.
Lecture 9, The Writing of Technical Papers – Methodologies for Excellence (Part I) (17, June, 14:00-15:30)
Lecture 10, The Writing of Technical Papers – Methodologies for Excellence (Part II) (18, June, 14:00-15:30)
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