"An extrusion-based additive manufacturing process, called the Ceramic On-Demand Extrusion (CODE) process, for producing three-dimensional ceramic components with near theoretical density was developed. In this process, an aqueous paste of ceramic particles with a very low binder content (<1 vol%) is extruded through a moving nozzle at room temperature. After a layer is deposited, it is surrounded by oil (to a level just below the top surface of most recent layer) to preclude non-uniform evaporation from the sides. Infrared radiation is then used to partially, and uniformly, dry the just-deposited layer so that the yield stress of the paste increases and the part maintains its shape. The same procedure is repeated for every layer until part fabrication is completed. Sample parts made of alumina and fully stabilized zirconia were produced using this process and their mechanical properties including density, strength, Young's modulus, Weibull modulus, toughness, and hardness were examined. Microstructural evaluation was also performed to measure the grain size, and critical flaw sizes were obtained. The results indicate that the proposed method enables fabrication of geometrically complex parts with superior mechanical properties. Furthermore, several methods were developed to increase the productivity of the CODE process and enable manufacturing of functionally graded materials with an optimum distribution of material composition. As an application of the CODE process, advanced ceramic components with embedded sapphire optical fiber sensors were fabricated and properties of parts and sensors were evaluated using standard test methods"--Abstract, page iv.
Leu, M. C. (Ming-Chuan)
Landers, Robert G.
Liou, Frank W.
Mechanical and Aerospace Engineering
Ph. D. in Mechanical Engineering
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- A novel freeform extrusion fabrication process for producing solid ceramic components with uniform layered radiation drying
- Mechanical characterization of parts produced by ceramic on-demand extrusion process
- Additive manufacturing and mechanical characterization of high density fully stabilized zirconia
- Adaptive rastering algorithm for freeform extrusion fabrication processes
- Optimal rastering orientation in freeform extrusion fabrication processes
- Composition optimization for functionally gradient parts considering manufacturing constraints
- A generic methodology for optimal design of three-dimensional functionally graded materials considering additive manufacturing constraints
- Advanced ceramic components with embedded sapphire optical fiber sensors for high temperature applications
xvii, 174 pages
© 2017 Amir Ghazanfari, All rights reserved.
Dissertation - Open Access
Electronic OCLC #
Ghazanfari, Amir, "Optimal design and freeform extrusion fabrication of functionally gradient smart parts" (2017). Doctoral Dissertations. 2594.