Interfacial Properties of Graded Titanium-Tantalum Alloy in Laser Powder Bed Fusion Additive Manufacturing

Monday, September 13, 2021: 3:00 PM
230 (America's Center)
Dr. Cherish Lesko, Ed.D. , Wright State University, Dayton, OH
Dr. Joy Gockel, Ph.D. , Wright State University, Dayton, OH
Mr. Joseph Walker , Universal Technology Company, Beavercreek, OH
Functionally graded material has the ability to adjust the material properties in a specific location towards an improvement in part function. Through the use of additive manufacturing (AM), a component can be fabricated with different material compositions throughout. The binary Titanium and Tantalum (Ti-Ta) alloy system is of great interest to many fields of engineering including biomedical and aerospace as a result of the unique properties it possesses. However, there remain several challenges in using Ti-Ta alloys in AM, including significantly different thermal behavior. In this work, the mechanical and material characterization of graded interfaces between varying compositions mixtures of Ti-Ta is explored. The deposition of the material is performed using a custom built laser powder bed fusion (LPBF) AM machine that allows for both horizontal and vertical grading throughout the powder bed. Additionally, in order to accommodate changing compositions, the process parameters required for each composition are investigated. Mechanical properties are evaluated using standard tension testing and fracture surface analysis of test specimens build with each gradient interface as well as samples of the individual compositions. Materials characterization includes optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and electron backscatter diffraction (EBSD). Results suggest that Ti-Ta can be successfully graded in both the horizontal and vertical directions. The mechanical property impact from the interfaces and the microstructural analysis will be discussed. The ability to grade material composition in multiple directions in LPBF AM provides to capability to fabricate complex geometries with spatially varying functional and structural properties tailored to the desired application.