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Articles 1 - 6 of 6
Full-Text Articles in Mechanical Engineering
Microstructure And Property Of Tib-Reinforced Ti Alloy Composites By Laser Metal Deposition, Yunlu Zhang, Jingwei Zhang, Frank W. Liou, Joseph William Newkirk
Microstructure And Property Of Tib-Reinforced Ti Alloy Composites By Laser Metal Deposition, Yunlu Zhang, Jingwei Zhang, Frank W. Liou, Joseph William Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
TiB-reinforced Ti alloy composites have been laser deposited with pre-alloyed Ti-6Al4V-1B powder. The microstructure of the as-deposited and heat treated composites have been characterized in detail using scanning electron microscope (SEM). A homogeneous dispersion of needle-like TiB precipitates is formed in the Ti-6Al-4V α/β matrix. TiB precipitates promote formation of small near equaxed α/β grain after β annealing process. The micro-hardness of the laser deposited composites increase 20-30% with 5 vol. % TiB precipitates compared to unreinforced Ti-6Al-4V deposits.
Freeform Extrusion Fabrication Of Titanium Fiber Reinforced Bioactive Glass Scaffolds, Albin Thomas, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas
Freeform Extrusion Fabrication Of Titanium Fiber Reinforced Bioactive Glass Scaffolds, Albin Thomas, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Although implants made with bioactive glass have shown promising results for bone repair, their application in repairing load-bearing long bones is limited due to their low fracture toughness and fairly fast degradation response in vivo. In this paper, we describe our investigation of freeform extrusion fabrication of silicate based 13-93 bioactive glass scaffolds reinforced with titanium fibers. A composite paste was prepared with 13-93 bioactive glass filled with titanium fibers (~16 µm in diameter and aspect ratio of ~250) having a volume fraction of 0.4 vol. %. This paste was then extruded to fabricate scaffolds with an extrudate diameter …
Effects Of Temperature On Aqueous Freeform Extrusion Fabrication, Jie Li, Ming-Chuan Leu, Greg Hilmas
Effects Of Temperature On Aqueous Freeform Extrusion Fabrication, Jie Li, Ming-Chuan Leu, Greg Hilmas
Mechanical and Aerospace Engineering Faculty Research & Creative Works
An experimental study was conducted to investigate the effect of temperature on ceramic parts produced by paste extrusion based additive manufacturing followed by sintering. A computer-controlled gantry system equipped with a piston extruder was used to extrude aqueous alumina paste. The system includes a temperature control subsystem that allows for freeform extrusion fabrication inside a low-temperature (<0°C) chamber. It can also be used for fabricating parts on a hot plate at ambient or higher temperatures (≥20°C). Test specimens were fabricated from aqueous aluminum pastes at -20°C in the low-temperature chamber and also on the hot plate at 40°C. The minimum angles achievable by these two processes for part fabrication, without use of support material, were compared. Also compared were the relative density and mechanical properties of the parts obtained after sintering. Microstructures were examined via scanning electron microscopy in order to obtain a deeper understanding of the effect of fabrication temperature.
A Microstructure And Hardness Study Of Functionally Graded Materials Ti6al4v/Tic By Laser Metal Deposition, Jingwei Zhang, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer
A Microstructure And Hardness Study Of Functionally Graded Materials Ti6al4v/Tic By Laser Metal Deposition, Jingwei Zhang, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer
Materials Science and Engineering Faculty Research & Creative Works
Crack free functionally graded material (FGM) Ti6Al4V-TiC has been fabricated by laser metal deposition (LMD) using TiC and Ti6Al4V powder which were premixed for different ratios. This study focuses on the influence of laser processing parameters and TiC compositional distribution on microstructure, Vickers hardness and phase. The microstructure is analyzed by scanning electron microscopy (SEM), x-ray diffraction (XRD) and hardness tests. Primary carbide, eutectic carbide and unmelted carbide are found in the deposit area. When laser power increased, the primary and secondary dendrite arm spacing increased. The laser power and scanning speed did not influence the Vickers hardness distribution significantly.
Laser Metal Deposition Of Functionally Gradient Materials From Elemental Copper And Nickel Powders, Sreekar Karnati, Todd E. Sparks, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer
Laser Metal Deposition Of Functionally Gradient Materials From Elemental Copper And Nickel Powders, Sreekar Karnati, Todd E. Sparks, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This work deals with the planning and fabrication of a functionally gradient copper-nickel composition via Laser Metal Deposition (LMD). Various compositions of copper and nickel were made by blending different weight percentages which were then sequentially deposited to fabricate functionally gradient copper-nickel thin-wall structures. Analyses were performed by sectioning the thin-wall samples for metallographic, hardness, X-ray diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDS) studies. The fabrication was studied for identifying and corroborating the deposited compositions and their corresponding gradients. XRD analyses were performed to identify the crystal structure of the deposit. EDS analysis was instrumental in identifying the variation …
Laser Surface And Sub-Surface Repair During Metal Additive Manufacturing, Prudvi Teja Ravi
Laser Surface And Sub-Surface Repair During Metal Additive Manufacturing, Prudvi Teja Ravi
Masters Theses
"This study examines the use of laser surface treatment to repair surface and subsurface defects. Numerical analysis was performed on laser surface melting using Gaussian heat distribution equations to analyze the depth of the melt pool created by the phenomena. Concurrently, a process map was developed with a planned set of experiments by varying the ranges of laser power and travel speed to determine the dimensions of the melt pool across the gamut. The data generated from both the process studies and the numerical analysis was then used to determine the ideal operating ranges of the process parameters to repair …