Additive Manufacturing of Metals: Microstructure, Properties and Alloy Development: Ti-/Co-/Cr-/Cu-based Alloys
Program Organizers: Prashanth Konda Gokuldoss, Tallinn University of Technology; Juergen Eckert, Erich Schmid Institute of Materials Science; Zhi Wang, South China University of Technology
Tuesday 2:00 PM
October 19, 2021
Room: A115
Location: Greater Columbus Convention Center
Session Chair: Rangasayee Kannan, Oak Ridge National Laboratory
2:00 PM
Designing a Beta Titanium Alloy with High Strength and Low Stiffness via Additive Manufacturing: Yi Dan Wang1; Sravya Tekumalla1; Matteo Seita1; 1Nanyang Technological University
Beta titanium alloys have been identified as the next generation bio-materials that will overcome the challenges associated with stress shielding, which stem from the high stiffness of Ti or Ti-6Al-4V.In this work, we fabricate a novel beta titanium alloy Ti-6.8Fe-1.8Cr-1.2Ni-0.2Mo using laser powder bed fusion (LPBF) by in-situ alloying of pure elemental powders. The resultant alloy is a single phase and consists of near-equiaxed grains with an average size of ~20 µm. We study the mechanical properties of this material by ultrasound, tensile, and microhardness tests. We find that the as-print samples have low, isotropic modulus of elasticity (̴ 60-70 GPa). Furthermore, we measure hardness and strength that are far superior to those of other beta-type Ti alloys and even match typical values found in Ti-6Al-4V. Owing to its low modulus, excellent mechanical properties, and biocompatible constituency, this novel lightweight Ti-6.7Fe-1.7Cr-1.2Ni-0.2Mo alloy is a promising candidate for load-bearing biomedical applications.
2:20 PM
Evaluation of In-situ Alloyed, Additively Manufactured GRCop-42: David Scannapieco1; David Ellis2; John Lewandowski1; 1Case Western Reserve University; 2NASA Glenn Research Center
A novel additive manufacturing (AM) technique has explored in-situ alloying of GRCop-42 (ISGRCop). While AM approaches using in-situ alloying typically involve eutectic alloys, GRCop-42 (Cu-4 at% Cr-2 at% Nb) is nearly pure copper dispersion strengthened with Cr2Nb dispersoids, usually produced via gas atomization. Elemental powders were used in combination with high-energy ball milling to demonstrate the ability to use in-situ alloying to create GRCop-42. Phase extractions and X-ray diffraction of the Cr2Nb dispersoids formed via in-situ alloying established a metric for success and repeatability. The most influential processing factors included prior ball milling and AM laser power. Comparison to conventionally processed materials showed the dispersoid morphology and distribution of ISGRCop were similar to conventional GRCop-42. These dispersoids control the strengthening mechanisms in GRCop-42, therefore the similarities indicate ISGRCop-42 should achieve similar mechanical properties as gas atomized GRCop-42.