Additive Manufacturing: Materials Design and Alloy Development II: Alloy Design- Titanium Alloys
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee, TMS: Integrated Computational Materials Engineering Committee
Program Organizers: Behrang Poorganji, Morf3d; James Saal, Citrine Informatics; Orlando Rios, University of Tennessee; Hunter Martin, HRL Laboratories LLC; Atieh Moridi, Cornell University
Wednesday 2:00 PM
February 26, 2020
Room: 6F
Location: San Diego Convention Ctr
Session Chair: James Saal, Citrine Informatics
2:00 PM Invited
Additive Manufacturing of Commercially Available Metastable β-Ti Alloys: Mohan Sai Kiran Kumar Yadav Nartu1; David Flannery1; Eugene Ivanov2; Srinivas Aditya Mantri1; Rajarshi Banerjee1; 1University of North Texas; 2Tosoh SMD Inc.
An additive manufacturing processes, laser engineered net shaping (LENS™), a near-net shape processing technology, has been used for the production of simple geometries of various commercially available β-Ti alloys. With regard to titanium alloys, the use of LENS™ technology has been well established; but the evolution of microstructure and texture, and their consequent influence on properties has yet to be fully understood. Pre-alloyed powder was used for the deposition of β-21S, β-C, and Ti-185. Site-specific microstructure and texture analysis, and mechanical properties along and across the build direction will be presented in this paper. The effect of Fe (eutectoid forming element in Ti-alloys) on the presence of β-flaking will also be discussed.
2:30 PM
Rapid Exploration of Compositionally Complex Alloys via Additive Manufacturing and Molecular Dynamics: Andrew Kustas1; Michael Melia1; Eric Schindelholz1; Shaun Whetten1; Joseph Michael1; Nicolas Argibay1; Michael Chandross1; 1Sandia National Laboratories
Compositionally Complex Alloys (CCAs), typically consisting of three or more elements in high concentration, are a class of materials that often possess remarkable structure-properties relationships. However, it is challenging to efficiently explore the multidimensional phase and composition space of these materials with conventional manufacturing routes. This talk presents recent efforts in implementing a high throughput alloy processing methodology to rapidly assess CCA structure-properties relationships via metal Additive Manufacturing (AM). The methodology is outlined and select case studies are presented to illustrate the efficacy of the approach. High throughput Molecular Dynamics simulations that provide rapid insight into material properties predictions are also presented. Preliminary results demonstrate the value proposition of utilizing high throughput experimental processing and computational tools to accelerate materials development for AM. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525
2:50 PM
Selective Laser Melting of Beta-type Ti-Nb Alloys for Bone Implants: Stefan Pilz1; Holger Schwab1; Patrick Langhelm1; Uta Kühn1; Annett Gebert1; 1Institute for Complex Materials, Leibniz IFW Dresden
Beta-type Ti-(40-45wt.%)Nb alloys with very low Young’s moduli of ~60 GPa and excellent biocompatibility are promising materials for load-bearing bone implants. Selective laser melting (SLM) of these alloys offers unique opportunities including the fabrication of scaffolds to adapt the stiffness and the creation of patient-specific designs. Samples of Ti-(40-45wt.%)Nb were successfully fabricated by SLM and as references state, by hot pressing of mechanically alloyed and gas atomized powders. Depending on the powder properties and the processing conditions, clear differences in the microstructure occurred. Reasons for this and their influence on the mechanical properties will be discussed. By SLM samples with very low residual porosity and with a structure of epitaxially grown beta-phase grains were obtained. In compression they showed high strength levels which were superior to those of hot pressed and cast ones. Funding by the DFG (SFB-Transregio79 and GE1106/12-1) and contributions of R. Schmidt and K. Zhuravleva are acknowledged.
3:10 PM
Ti-Nb Alloy with Location-dependent Properties Using Laser Additive Approach: Wenhao Lin1; Ji Ma1; 1University of Virginia/MSE Department
Titanium-Niobium (Ti-Nb) is one of the promising beta-type titanium shape memory alloys for biomechanical applications. Due to their metastable nature, these alloys can be tailored via thermo-mechanical processing to have a modulus from 30-110 GPa based on our recent findings. By applying additive manufacturing methods, these alloys can be further customized to create regional differences in the mechanical properties of a part. By applying different scan strategies and processing parameters at the different regions, we observe a material with location-varying mechanical properties – for example, differences in the local stiffness. This manufacturing method provides an additional degree of freedom in material design and will be useful for the applications such as biomedical implants which require multiple different properties within the same part but is often limited in part geometry and number of materials used.
3:30 PM
Design of New Titanium Alloy for Additive Manufacturing with the CALPHAD Method: Zhi Liang1; Richard Ricker1; Ursula Kattner1; Carelyn Campbell1; 1National Institute of Standards and Technology
The widespread use of titanium alloys is limited by their high cost, largely resulting from the metal removal process during subtractive manufacturing. Additive manufacturing (AM) provides a potential cost-effective net-shape manufacturing process by maximally avoiding the metal removal cost factor. However, current commercial titanium alloys are not designed for AM processes. The present work is focused on applying the Calculation of Phase Diagrams (CALPHAD) method to the design of a new Ti-Al-Fe based alloy for an AM process. The single laser scanning (SLS) experiment is conducted, coupled with CALPHAD predictions, to investigate the potential performance of a new alloy in a selective laser melting (SLM) process, including scanning topography, analysis of the as-scanned microstructure and comparison with computational results.
3:50 PM Break
4:05 PM Invited
Microstructural Control for Additive Manufacturing of Metal Alloys—an Advanced Microscopy Approach: Simon Ringer1; 1University of Sydney
AM is emerging as a gateway to unexplored metallurgical phenomena that must be understood to open the full potential of the technology in terms of cost, design-flexibility and design-complexity. The steady-state conditions assumed during traditional manufacturing processes are not valid in AM, because of the spatial and temporal transients imposed by the abrupt, cyclical changes in energy delivery. As a result, the intrinsic microstructural heterogeneity throws new challenges at the familiar notion of a ‘microstructure-property’ relationship. This lecture will present recent advances in the way that the electron microscope and the atom probe microscope have enabled insights into this complex relationship. Recent breakthrough methodological advances in Transmission Kikuchi Diffraction, 3D-electron backscattered diffraction, aberration corrected scanning transmission electron microscopy, and atom probe microscopy will be presented in the context of how these techniques are enabling the generation of critical quantitative data for AM process control.
4:35 PM
Development of New Ti-64 Modified Alloys for Additive Manufacturing with Columnar to Equiaxed Transition: Nevin Taylor1; Hamish Fraser1; Brian Welk1; Zachary Kloenne1; Andrew Baker2; 1Ohio State University; 2Boeing
There are a number of defects associated with the additive manufacturing of titanium alloys that must still be addressed. One such issue is the formation of coarse columnar grains that form parallel to the growth/deposition direction leading to anisotropic properties. In this research, the use of alloying elements, specifically the Beta-eutectoid stabilizers, have been shown to induce a columnar to equiaxed transition through modification of the solidification mechanism. A Laser Engineered Net Shaping (LENS) AM device with two powder hoppers has been used to create gradient builds by varying the alloying elements of interest, narrowing down the composition of the columnar to equiaxed transition and demonstrating the effect of composition on microstructure. Subsequent heat treatments have been investigated to optimize the mechanical properties of the new Ti-64 modified alloys, which show promising results for use in wide-spread applications.
4:55 PM
Application of a Thermodynamics-informed Materials Design Simulator for Microstructure Control During AM: Aurelien Perron1; John Roehling1; Tien Roehling1; Nicholas Calta1; Bey Vrancken1; Joel Berry1; Thejaswi Tumkur Umanath1; Patrice Turchi1; Vincenzo Lordi1; Joseph McKeown1; Manyalibo Matthews1; 1Lawrence Livermore National Laboratory
A Materials Design Simulator (MDS) – based on coupling a CALPHAD thermodynamic software with a global constrained search engine – will be presented to discover new Titanium-X (X = Nb, Sn, Ta, Ti, Zr) alloys with optimal composition for microstructural control during additive manufacturing. Results for complex multi-component alloys will be presented with an emphasis on the columnar to equiaxed transition (CET). A new alloy designed using our MDS will be presented with experimental characterizations confirming the CET. The presentation will conclude with the prospect of additional developments for improving the efficiency of the search for high-performance materials for AM.Prepared by LLNL under contract DE-AC52-07NA27344, and supported by the Laboratory Directed Research and Development Program under project tracking code 18-SI-003, and the Critical Materials Institute, an Energy Innovation Hub funded by the U.S. DOE, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office.
5:15 PM
Alloy-dilution Effects and Mechanical Response in Wire-arc Additively-manufactured Alloy-alloy Composites Built Using Ti-6Al-4V and Commercially-pure Titanium: Alec Davis1; Cameron Breheny1; Jonathon Fellowes1; Uzoma Nwankpa2; Filomeno Martina2; Jialuo Ding2; Thays Machry3; Philip Prangnell1; 1The University of Manchester; 2Cranfield University; 3Airbus
The feasibility of using high deposition rate Wire-Arc Additive Manufacturing (WAAM) to print dual-alloy microstructure ‘Alloy-Alloy composites’ (AACs) has been explored. Alternating wire feeds of commercially-pure Ti (CPTi) and Ti-6Al-4V (Ti64) were used to print an AAC component with a dual-‘phase’ microstructure, which was characterised using mechanical testing, electron microscopy, and electron probe microanalysis. The results show that, due to a high level of dilution during deposition and efficient liquid-phase mixing, the component consisted of layers with an alternating bimodal composition, where each Ti64 and CPTi track deposit had a composition leaner or richer, respectively, than the starting wire compositions. The effects of chemical mixing on the fracture behaviour and microstructure are explored, as well as the surprising result that using alternating alloys promoted β-grain nucleation and refined the normal coarse columnar grain structure seen in WAAM deposits. The impact of these findings on future AAC WAAM research is discussed.