Additive Manufacturing: Materials Design and Alloy Development III -- Super Materials and Extreme Environments: High Temperature and Heavy Materials
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee
Program Organizers: Behrang Poorganji, Morf3d; Hunter Martin, HRL Laboratories LLC; James Saal, Citrine Informatics; Orlando Rios, University of Tennessee; Atieh Moridi, Cornell University; Jiadong Gong, Questek Innovations LLC
Tuesday 2:00 PM
March 16, 2021
Room: RM 3
Location: TMS2021 Virtual
Session Chair: Atieh Moridi, Cornel
2:00 PM
Process Development for the Selective Laser Melting of Tungsten Carbide-nickel Matrix Composites: Edgar Mendoza Jimenez1; Baby Reeja-Jayan1; Jack Beuth1; 1Carnegie Mellon University
In this work, laser powder bed fusion (LPBF) is used for the additive manufacturing of composite samples consisting of tungsten carbide particles with a nickel binder. Such process can become a viable low-energy alternative to the conventional production of ceramic-metal composites for applications including tooling, electronics, and wear components. Single track experiments are used to evaluate the melting behavior of the composite material. Samples are then printed with of process parameters that adequately melted the material. The density, microstructure, and functional properties of these samples are measured. Highly dense (>98%) samples are successfully manufactured and analyzed as a function of LPBF parameters. Macro- and microdefects resulting from the laser processing are also discussed. A methodical approach to evaluate an acceptable processing region is presented and used to investigate the feasibility of additively manufacturing tungsten carbide-nickel composites via LPBF.
2:20 PM
Laser Powder-bed Fusion Austenitic Steels with Superior Creep Resistance: Sebastien Dryepondt1; Peeyush Nandwana1; Kinga Unocic1; Patxi Fernandez-Zelaia1; Ying Yang1; Rangasayee Kannan1; Yousub Lee1; Fred List1; 1Oak Ridge National Laboratory
It is well known that extremely fast cooling rates during laser powder-bed fusion (LPBF) can result in materials with unique microstructures. For 316L stainless steel fabricated by LPBF, the formation of sub-grain cellular structure with high dislocation density has been linked to superior tensile properties. This cellular structure offers also a new route for the development of high temperature LPBF steels with the nucleation of nanoscale strengthening precipitates in the cell walls. High temperature 310 and 347-type steels were, therefore, fabricated by LPBF. Fine NbC precipitates were found at the cellular walls leading to high yield strength at temperatures up to 900C. The creep lifetimes of the LPBF 310-type steel at 700-800C were ~3 times and ~1.5 times higher than the creep lifetime of cast 310 along and perpendicular to the build direction, respectively. The steel microstructure evolution at high temperature with and without an applied stress will be discussed.
2:40 PM
Development of Multi-principle Element Alloys for Oxidation Resistant Coatings Applied with Additive Manufacturing: Jose Loli1; Yining He1; Amish Chovatiya1; Zachary Ulissi1; Bryan Webler1; Maarten De Boer1; Jack Beuth1; 1Carnegie Mellon University
Multi-Principle Element Alloys (MPEAs) are shown to have exceptional properties and demonstrate promise as a new methodology for alloy discovery. We focus on screening alloys that can be deposited as coatings by additive manufacturing and will exhibit high oxidation resistance. To determine candidate MPEAs, we simulated CALPHAD data of 2000 randomly selected, 5- and 4- element, non-equimolar compositions in our chosen 14-element palette space. Because oxidation behavior is difficult to predict for MPEAs, we made use of a regression model fitted on experimental data found in literature. Candidate alloys were screened, arc-melted, characterized, and tested for oxidation. To determine their compatibility with additive manufacturing, cracking susceptibility was tested with single laser track experiments. Given the complex interplay between oxidation resistance, MPEAs, and additive manufacturing, we expect our balanced modeling, machine learning, and experimental approach will lend insight in future MPEA development.
3:00 PM
Reactive Selective Laser Synthesis and Additive Manufacturing of Ultra-high Temperature Ceramics: Adam Peters1; Dajie Zhang2; Alberto Hernandez1; Michael Brupbacher2; Dennis Nagle1; Tim Mueller1; James Spicer1; 1Johns Hopkins University; 2The Johns Hopkins Applied Physics Laboratory
Ultra-high-temperature ceramics (UHTCs, e.g. SiC, ZrC, TiC, TiN) are optimal structural materials for applications that require extreme temperature resilience (Mp>3000°C), resistance to chemically aggressive environments, wear, and mechanical stress. To date, processing UHTC’s with laser-based additive manufacturing (AM) has not been fully realized due to a variety of obstacles: high laser energy densities are required to overcome slow diffusion rates, yet localized laser exposure induces decomposition or microcracking when a UHTC’s thermal capabilities are exceeded. To circumvent such issues, we propose an alternative technique for AM-UHTC processing by synthesizing the non-oxide material in-situ, during part formation. Specifically, we demonstrate that by employing laser-induced gas-solid reactions, reaction-bonded, near net-shaped UHTCs may be fabricated using AM compatible techniques. While this method presents a host of additional processing considerations (e.g. reaction kinetics, precursor microstructure, etc.), we demonstrate how this reactive approach may be viable for AM of refractory carbide, nitride, and composite materials.
3:20 PM
The Mechanisms Behind the Effect of Oxygen on DED AM Ti Alloy Build: Caterina Iantaffi1; Yunhui Chen1; Samuel J. Clark1; Robert C. Atwood2; Eral Bele1; Martina Meisnar3; Thomas Rohr4; Lertthanasarn Jedsada5; Minh-Son Pham5; Peter D. Lee1; 1UCL Mechanical Engineering; 2Diamond Light Source Ltd; 3ESA-RAL Advanced Manufacturing Laboratory; 4ESA-ESTEC; 5Imperial College London
To prevent oxygen contamination, Laser Additive Manufacturing (LAM) techniques are normally operated in an inert gas chamber. An alternative method, useful for large builds and component reparation, is the application of a localised inert gas shield. We investigate the effect of oxygen contamination on Ti6242 during directed energy deposition (DED) additive manufacturing using an inert gas chamber compared to a gas shield. It has been discovered that, in gas shield mode, the amount of oxygen absorbed from the atmosphere was sufficient to reverse the Marangoni flow leading to an alteration of the molten pool morphology, strongly affecting porosity formation. Furthermore, the high oxygen level resulted in the precipitation of primary α phase, and refined the grain structure. The commonly developed Widmanstätten microstructure was completely suppressed. The presented results elucidate the influence of oxygen contamination in additively manufactured Ti alloys, and help identify improved industrial practises for titanium additive manufacturing.
3:40 PM
A Novel Heat Treatment Design to Overcome Inferior Creep Behaviour of SLM Processed IN738LC Alloy: Haoyu Song1; 1MCAM, Monash University
Additive manufacturing (AM) has received increasing attention in gas turbine applications due to its advantages in overcoming geometrical limitation and simplifying the manufacturing process. This presentation reports on the selective laser melting (SLM) of the high-strength, Ni-based superalloy IN738LC widely used in gas turbines. SLM-produced IN738LC is known for its problematic inferior creep properties compared with the cast counterpart. In this work, the inferior creep properties were firstly investigated based on the detailed as-SLM microstructural study. A systematic research on several heat treatment schemes was then conducted, revealing the relationships between grain growth, precipitation kinetics and boundary phase pinning. A novel heat treatment scheme is eventually proposed based on the above findings, which enhances the grain structure and ultimately improves the creep resistance. The new heating scheme provides SLM-produced IN738LC alloy with creep performance comparable to that from conventional process, enabling further adaption of SLM on gas turbine components.