Browsing by Subject "functionally graded material"

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Design and Fabrication of Functionally Graded Material from Ti to γ-TiAl by Laser Metal Deposition
(University of Texas at Austin, 2017) Chen, Xueyang; Yan, Lei; Newkirk, Joe; Liou, Frank
Functionally graded material (FGM) is one kind of advanced material characterized by a gradual change in properties as the position varies. The spatial variation of compositional and microstructure over volume is aimed to control corresponding functional properties. In this research, when 100% γ-TiAl was directly deposited on pure Ti substrate, cracks were formed within the γ-TiAl layer. Then a six-layer crack-free functionally graded material of Ti/TiAl was designed and fabricated by laser metal deposition (LMD) method, with composition changing from pure Ti on one side to 100% γ-TiAl on the other side. The fabricated FGM was characterized for material properties by a variety of techniques. The chemical compositions, microstructure, phases, and hardness of the composite were characterized by Scanning Electronic Microscope (SEM), Optical Microscope (OM), Energy Dispersive X-ray Spectroscopy (EDS), and hardness testing. The microstructure and chemical compositions in different layers were studied.
Investigating the Impact of Functionally Graded Materials on Fatigue Life of Material Jetted Specimens
(University of Texas at Austin, 2017) Kaweesa, Dorcas V.; Spillane, Daniel R.; Meisel, Nicholas A.
The capability of Additive Manufacturing (AM) to manufacture multi-materials allows the fabrication of complex and multifunctional parts with varying mechanical properties. Multi-material AM involves the fabrication of 3D printed objects with multiple heterogeneous material compositions. The material jetting AM process specifically has the capability to manufacture multi-material structures with both rigid and flexible material properties. Existing research has investigated the fatigue properties of 3D printed multi-material specimens and shows that there is a weakness at the multi-material interface. This paper seeks to investigate the effects of gradual material transitions on the fatigue life of 3D printed multi-material specimens, given a constant volume of flexible material. In order to examine the fatigue life at the multi-material interface, discrete digital-material gradient steps are compared against the true functional gradients created through voxel-level design. Results demonstrate the negative effects of material gradient transitions on fatigue life as well as the qualitative material properties of true versus discrete gradients.
Planning the Process Parameters During Direct Metal Deposition of Functionally Graded Thin-Walled Parts Based on a 2D Model
(University of Texas at Austin, 2016) Yan, Jingyuan; Battiato, Ilenia; Fadel, Georges M.
The need for functionally graded material (FGM) parts has surfaced with the development of material science and additive manufacturing techniques. Direct Metal Deposition (DMD) processes can locally deposit different metallic powders to produce FGM parts. Yet inappropriate mixing of materials without considering the influence of varying dilution rates and the variation of material properties can result in inaccurate material composition ratios when compared to the desired or computed compositions. Within such a context, this paper proposes a 2D simulation based design method for planning the process parameters in the DMD manufacturing of designed thin-walled parts. The proposed scheme is illustrated through two case studies, one of which is a part with one-dimensional varying composition and the other with two dimensional variation. Using the proposed method, the process parameters can be planned prior to the manufacturing process, and the material distribution deviation from the desired one can be reduced.
Review of Current Problems and Developments in Large Area Additive Manufacturing (LAAM)
(University of Texas at Austin, 2021) Crisp, Tyler G.; Weaver, Jason M.
Large Area Additive Manufacturing (LAAM), also known as Big Area Additive Manufacturing (BAAM), is a screw extrusion, pellet-fed additive manufacturing technology. The large build area, rapid build speed, and inexpensive pelletized feedstock of LAAM are major advantages over conventional AM methods. LAAM has a large variety of applications in areas including energy, automotive, aerospace, high volume production, and composite molds. However, LAAM is not without its challenges. The largest challenges LAAM faces include mechanical properties, uniformity and precision, and predictability of composite material properties. The goal of this paper is to present current research regarding challenges in LAAM, methods of addressing those challenges, developments, and applications, as well to highlight further research to be done.