Author ORCID Identifier
Semester
Summer
Date of Graduation
2024
Document Type
Dissertation
Degree Type
PhD
College
Statler College of Engineering and Mineral Resources
Department
Mechanical and Aerospace Engineering
Committee Chair
Konstantinos Sierros
Committee Co-Chair
Xingbo Liu
Committee Member
Xingbo Liu
Committee Member
Edward Sabolsky
Committee Member
Bruce Kang
Committee Member
Chih-Hung Chang
Abstract
There is currently a burgeoning interest in developing 3D printed metal structures with inherent porosity and sufficient mechanical properties for mass customization in the biomedical field. Current approaches for 3D printing of biocompatible metals rely on powder-bed fusion methods which are energy intensive and utilize large amounts of metal powder that is challenging to recycle. In addition, such methods aim on producing dense parts and porosity generation, within the printed part, is challenging due to the complex physics of the melting pool. Here, a relatively new and promising approach is undertaken to study the 3D printing of inherently porous structures with appropriate mechanical properties towards biomedical applications. In particular, the direct ink writing (DIW) method is employed as a means to induce porosity within the printed parts by formulating, printing, and post-processing model ‘bio-inks’. During DIW a yield stress fluid (i.e., ink) is robotically extruded on digitally predefined substrate locations to build parts in a layer-by-layer fashion. Advantages of DIW include almost no material waste, ease of fabrication, and ink formulation using disparate starting precursors. Ink design and formulation studies using biopolymer binders such as xanthan gum and cellulose along with a stainless-steel hard phase led to formulation of controllably extrudable viscoelastic fluids for a range of resolutions. Ink characteristics such as yield stress, flow transition index - determining ink ductility/brittleness - are elucidated and related to printability while the limitations of current rheological models for non-Newtonian inks are highlighted. Furthermore, post-processing studies are conducted to establish relationships between different bio binder compositions (and their binary concentrations) and the hard phase, induced porosity, and resulting mechanical properties. Taking advantage of different binder conformations, the induced porosity and mechanical behavior of 3D printed and sintered parts are found to exhibit new synergies. Macro porosities and mechanical properties within a range required for potential biomedical parts are achieved and demonstrated.
Recommended Citation
Aysal, Havva Eda, "Inherently Porous Metal Structures with Sufficient Mechanical Properties Through Direct Writing of Bio-based Inks" (2024). Graduate Theses, Dissertations, and Problem Reports. 12541.
https://researchrepository.wvu.edu/etd/12541
Embargo Reason
Publication Pending
Included in
Manufacturing Commons, Mechanics of Materials Commons, Metallurgy Commons, Polymer and Organic Materials Commons, Tribology Commons