Additive Manufacturing and Innovative Powder/Wire Processing of Multifunctional Materials: Shape Memory Alloys and Steels I
Sponsored by: TMS Functional Materials Division, TMS Materials Processing and Manufacturing Division, TMS: Magnetic Materials Committee, TMS: Additive Manufacturing Committee, TMS: Powder Materials Committee
Program Organizers: Daniel Salazar, BCMaterials; Markus Chmielus, University of Pittsburgh; Emily Rinko, Honeywell Fm&T; Emma White, DECHEMA Forschungsinstitut; Kyle Johnson, Sandia National Laboratories; Andrew Kustas, Sandia National Laboratories; Iver Anderson, Iowa State University Ames Laboratory
Tuesday 8:00 AM
March 21, 2023
Room: 23C
Location: SDCC
Session Chair: Andrew Kustas, Sandia National Laboratories
8:00 AM Invited
Additive Manufacturing of Cu-based Shape Memory Alloys: Challenges and Perspectives: Jose San Juan1; Mikel Pérez-Cerrato1; Lucía Del-Río1; Ernesto Urionabarrenetxea2; Josu Leunda3; Iban González4; Iban Quintana3; Fernando Carreño5; Nerea Burgos2; María Nó1; 1Universidad del Pais Vasco; 2CEIT-Basque Research and Technology Alliance (BRTA); 3TEKNIKER, Basque Research and Technology Alliance (BRTA); 4LEITAT; 5CENIM-CSIC
Shape memory alloys (SMAs) are functional materials exhibiting specific shape memory and superelastic effects. Nowadays additive manufacturing (AM) offers new processing capabilities of SMA and is already being applied to NiTi-based SMAs, but Cu-based SMAs are also attracting the attention because of some advantages over the NiTi SMAs. However, AM of Cu-based SMAs constitute a challenge due to the inherent processing difficulties associated with its high thermal conductivity and the microstructure required to obtain good functional properties.In the present work the same atomized powders of Cu-Al-Ni SMA were processed by two different additive manufacturing methods, laser powder bed fusion and laser metal deposition, and the processing parameters were optimized for each method. The microstructure and the mechanical properties of shape memory and superelasticity obtained in each case will be comparatively analyzed, being also compared with the ones obtained by the classical powder metallurgy route processed by hot rolling.
8:30 AM
Improving Tensile Strengths of Laser-Direct Energy Deposited (L-DED) NiTiHf Alloys by Printing Dislocation Structures: Soumya Mohan1; Aaron Stebner1; 1Georgia Institute of Technology
Additive manufacturing of NiTi shape memory alloys for biomedical applications requiring superelasticity is challenging due to the poor tensile performance of as-printed parts. Improving tensile strength by traditional approaches like aging heat treatments and cold work to add precipitation strengthening and dislocation strengthening respectively, are difficult to adapt to the complex geometries of AM NiTi parts. We attempted to improve tensile strengths of AM NiTi alloys by introducing a ternary alloying element, that would actively segregate during AM solidification, and help print dislocation structures into the as-solidified microstructure. Candidate ternary alloying elements were explored through non-equilibrium Scheil simulations, and Hf was selected for printing NiTiHf alloys. Hf segregation was indeed observed at the solidification cell boundaries in the as-printed microstructure for several samples printed using Laser Direct Energy Deposition process with varying power and scan speeds. Transmission electron microscopy will be used to confirm the presence of such dislocation structures.
8:50 AM
Controlling Martensitic Transformation Characteristics in Defect-free NiTi Shape Memory Alloys Fabricated Using Laser Powder Bed Fusion: Ibrahim Karaman1; L. Xue1; Kadri Atli1; Chen Zhang1; Alaa Elwany1; Raymundo Arroyave1; 1Texas A&M University
Laser Powder Bed Fusion (L-PBF) was utilized to fabricate fully dense, near-equiatomic and Ni-rich NiTi shape memory alloys (SMAs) which exhibited tensile ductility up to 16%, shape memory strain of 6%, and tensile superelasticity up to 6%. The selection of optimum processing parameters that yielded fully dense parts was guided by a process optimization framework based on an analytical model to predict the melt pool dimensions. The framework also included single-track experiments to validate the model predictions and a criterion for the maximum allowable hatch spacing to prevent the formation of porosity. This framework allowed for constructing L-PBF processing maps for NiTi SMAs and revealed that fully dense parts could be printed over a wide range of process parameters. The flexibility of parameter selection to print defect-free NiTi SMAs and composition control by preferential evaporation of Ni opens the possibility to print functional NiTi SMA parts without post-processing.
9:10 AM
Electron Beam Powder Bed Fusion of Binary Ni-Ti Shape Memory Alloys – On the Impact of TiC on the Functional Properties: Philipp Krooss1; Christian Lauhoff1; Tobias Gustmann2; Julia Hufenbach2; Thomas Niendorf1; 1Institute of Materials Engineering, University of Kassel; 2Leibniz Institute for Solid State and Materials Research Dresden
Ni-Ti shape memory alloys (SMA) still gain a lot of attention as promising candidates for actuation and damping applications. Since well-established thermomechanical processing routes widened potential applications, innovative 4D printing studies using powder bed based additive manufacturing processes are limited. However, the possibility to process near-net shaped actuators and dampers still motivates recent research dealing with additive manufacturing processes. Especially the characterization of microstructural and functional properties in correlation with process parameters are in focus. The present study focuses on electron beam powder bed fusion of a Ni-Ti SMA and the impact of an increased carbon content, which originates from the powder material that has been processed via vacuum induction melting gas atomization (VIGA). Chemical and microstructural analysis were conducted to address the impact of the chemical composition on the functional properties. The results reveal a high reversibility as well as excellent cyclic stability of the superelastic material properties.
9:30 AM
Additive Manufacturing of NiTi Shape Memory Alloy via Laser Metal Deposition and Laser Powder Bed Fusion: Haopeng Shen1; Kun Yang1; Daniel East1; Daniel Liang1; Anthony Murphy1; Ma Qian2; Ryan Watkins3; Douglas Hofmann3; 1CSIRO; 2RMIT; 3Jet Propulsion Laboratory
Additive manufacturing (AM) has opened new opportunities for free design of bespoke parts and property control for different applications of shape memory alloys (SMAs). This work discusses challenges and opportunities in AM of NiTi SMAs for biomedical and space applications using laser metal deposition (LMD) and laser powder bed fusion (LPBF). Crack-free bonding between functional materials and structural materials is highly desired in integrated designs for light-weight applications. Using LMD, we studied the dissimilar material bonding between the NiTi SMA and various structural materials (Al alloy, Ti alloy and steel). Control of the cracking was explained by studying the microstructure and thermal history. We also presented the comparative study of the LMD and LPBF processes to evaluate the microstructure uniformity, phase transformation temperature and material properties. This study provides insights into cost-effective alloy development using powder mixture, large-format additive manufacturing, and process control for reliable shape memory or superelastic properties.
9:50 AM Break
10:05 AM Invited
Opportunities and Challenges for Fabrication of Electrical Machine Components by Additive Manufacturing: Marco Simonelli1; Ian Ashcroft1; Nesma Aboulkhair1; Michele Garibaldi1; Leonidas Gargalis1; Cassidy Silbernagel1; Julan Wu1; Richard Hague1; 1University of Nottingham
This talk will present several opportunities of application of additive manufacturing for the realisation of next generation electrical machines. Emphasis will be spent on the description of successful examples of Laser-Powder Bed Fusion (L-PBF) of iron cores (silicon steel), permanent magnets (NdFeB) and coil conductors (Cu) in a variety of machine topologies. While it is now clear that L-PBF presents unique advantages to design geometrically optimised components, it is proving challenging to reach adequate level of material performance. The talk will examine the typical challenges that the named materials pose to L-PBF processing. Taking the magnetic materials as an example, we will present our experience on how to combine laser parameters and alloy composition to develop desirable microstructures. The talk will then conclude by presenting aspects of the fabrication of Cu and multi-material assemblies (steel-Cu) with the use of a novel multi-beam L-PBF platform equipped with multi-material recoater.
10:35 AM
Consequences of Powder Reuse on Microstructure Evolution during Laser Powder Bed Fusion of 316L Stainless Steel: Madelyn Madrigal-Camacho1; Mitchell Keeler1; Joy Gockel1; Suveen Mathaudhu1; 1Colorado School of Mines
Successive reuse processes lead to changes in powder morphology, chemical composition, and microstructure in the recovered powder. In the case of 316L stainless steel, literature reports successful powder reuse within 12-30 consecutive cycles, however, a detailed understanding of the effect of powder degradation on the final part quality is unexplored. Therefore, the primary goal of this study is to enable the rapid degradation of the powder feedstock under conditions which can be transferable to manufacturing processes. With this approach, the effects of the thermally dynamic powder-laser interactions and the instrument process parameters on reused powder characteristics can be explored. The results provide insight to the consequences of the melt pool behavior with the instabilities of the altered powder, solidification modes, microstructure, evolution of spatter and porosity in the as-built components. These observations point to important considerations to design a standard method for reusing powder in powder bed fusion processes.
10:55 AM
Directed Energy Deposition of a Martensitic Steel – Microstructure Evolution and Mechanical Response: Shubham Chandra1; Mehmet Cagirici1; Upadrasta Ramamurty1; 1Nanyang Technological University
Metal additive manufacturing has been researched over the past couple of decades for the fabrication and characterization of novel alloy systems. However, for its advancement, it is necessary for metal AM techniques to produce parts with standard compositions that can go head-to-head against their conventional counterparts in the most widespread applications. The tooling industry is one that can reciprocate the benefits obtained from metal AM by providing means of quick testing and standardisation of as-built parts. This talk presents the microstructural investigations and mechanical response obtained in H13 tool steel parts printed by the DED process. It also provides a framework for process parameter optimization in DED processes where the complex interplay of process parameters governs the printability of a part. The DED’ed tool steel parts printed with the optimized process parameters showcase > 99.95%-part density in the as-built condition – free from geometrical constraints and possessing superior mechanical properties.
11:15 AM
Fabrication of HSLA Steel Si-Bronze Aluminum Functionally Graded Material Using Wire Arc Additive Manufacturing: Hanadi Salem1; Marwan El-Husseiny2; Ehab El-Danaf2; 1American University in Cairo; 2Cairo University
Wire arc additive manufacturing (WAAM) is a promising technology in the production of large-scale functionally graded material components with high efficiency and relatively low cost. In the present study, a high-strength low alloy (HSLA) steel-Si-bronze-aluminum functionally graded material is manufactured, where Si-bronze will be sandwiched between HSLA steel and AA5456 aluminum alloy. The WAAM-ed functionally graded product combines the high strength and hardness of HSLA steels with the lightweight and toughness of aluminum. Si-bronze sandwiched layers provide the proper mechanical property transition and enhanced diffusion and hence the integrity of the processed functionally graded blocks. A parametric study for the deposition parameters is conducted to mitigate the thermal mismatch of multi-materials built layers aiming for minimizing the thermal stresses produced during processing. Mechanical and microstructural evolution of the built blocks, especially within the fusion zone between the dissimilar alloys are investigated.