Additive Manufacturing of Metals: Applications of Solidification Fundamentals: Solidification of Advanced Materials I
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee, TMS: Solidification Committee
Program Organizers: Wenda Tan, The University of Michigan; Alex Plotkowski, Oak Ridge National Laboratory; Lang Yuan, University of South Carolina; Lianyi Chen, University of Wisconsin-Madison
Wednesday 2:00 PM
March 22, 2023
Room: 21
Location: SDCC
Session Chair: Lianyi Chen, University of Wisconsin-Madison
2:00 PM Invited
Solidification Cracking in Additive Manufacturing of Metals: Seyed Mohammad Hojjatzadeh1; Minglei Qu1; Ali Nabaa1; Qilin Guo1; Luis I. Escano1; Lianyi Chen1; 1University of Wisconsin-Madison
Solidification or hot cracking is commonly observed in additive manufacturing processes of metals such as aluminum and nickel alloys, which drastically affects the mechanical and physical performance of additively manufactured materials, hindering their full potential for advanced applications.In this research, we use in-situ x-ray imaging technique with high temporal and spatial resolution to study the formation and dynamics of hot cracking during laser powder bed fusion (LPBF) additive manufacturing (AM) of aluminum alloy in real time. We will provide the detailed analysis into the dynamics and physics of solidification cracking, thereby providing insights for process optimization for crack mitigation during additive manufacturing of metals.
2:20 PM
A Novel Method for Determining Printability of Aluminum Alloys for LPBF Applications: John O`Connell1; Bhaskar Majumdar1; Timothy Nice1; Nathaniel Badgett1; Mohammad Choudhury1; 1New Mexico Institute of Mining and Technology
The rapid solidification seen in laser powder bed fusion (LPBF) additive manufacturing causes issues with segregation and cracking especially in aluminum alloys. This makes research and development of alloys that print well of paramount importance to the materials community. The traditional method of alloy development for LPBF applications can be cost prohibitive due to the need to produce powders to test printability. This work sets out to show that lasering melt pools into arc melted samples, referred to as line scans, of the aluminum alloy of interest is an effective method to determine the alloys printability without having to fabricate a custom powder. SEM and EDS analysis of transverse sections on the line scans are examined looking for cracks in the melt pools, and segregation of alloying elements. Aluminum alloys of interest include Al-Mg-Cu, Al-Si-Mg, Al-Sc/Zr, and Al-Sc-Sm.
2:40 PM
An Oxygen-stabilized Face-centred Cubic Phase in Additively Manufactured Ti-6Al-4V: Hao Wang1; Qi Chao2; Xiangyuan Cui1; Zibin Chen1; Andrew Breen1; Wei Xu2; Sophie Primig3; Simon Ringer1; Xiaozhou Liao1; 1University of Sydney; 2Deakin University; 3UNSW Sydney
(MURI and AUSMURI Collaborative Research)The existence of a face-centred cubic (FCC) titanium (Ti) phase in Ti alloys remains under debate over the past decades. In general, Ti has high chemical affinity with interstitials such as oxygen, leading to the formation of intermetallic compounds and dramatically diminishing ductility. Here, we demonstrate that interstitial oxygen can be incorporated into a Ti-6Al-4V alloy to improve its mechanical properties through the formation of an oxygen-containing FCC solid solution phase. This is achieved via selective laser melting, where the combination of high thermal stresses and thermal gradients facilitates a new phase transformation. Electron microscopy, atom probe tomography and density functional theory were used to reveal the crystallography and chemical composition of the new FCC phase. Our mechanical testings revealed that the introduction of the FCC phase dramatically enhances both the strength and ductility of the material.
3:00 PM
Analysis of Functionally Grade Materials Printing via Direct Energy Deposition Using Thermodynamic and Physical Simulation: Jorge Valilla1; Damien Tourret1; Ilchat Sabirov1; 1IMDEA Materials
Additive manufacturing of metallic materials enables manufacturing of functionally graded materials (FGMs) that show a gradual change in composition within a part. This comes as a great option when dealing with dissimilar joints or to create location-specific properties. Here, we investigate material compatibility and explore processing parameters for parts graded from a stainless steel 316L and a Ni-based superalloy IN718 by combining: (1) advanced characterization (SEM, EDX, EBSD, micro-hardness) of quality, microstructure and properties of graded samples manufactured by direct energy deposition (DED); (2) computational thermodynamics (CalPhaD) exploration of phase diagrams and assessment of thermal properties along the material gradient; and (3) original physical simulations (Gleeble 3800) to investigate material compatibility and diffusion at the interface. This study explores fundamental mechanisms of microstructure selection and properties in metallic FGMs and investigates the appearance of defects, e.g. (micro-)cracks, and phases/constituents in specific regions of the compositional gradient.
3:20 PM
Comparing Microstructure and Mechanical Properties of AlSi10Mg Alloy Produced by Laser Powder Bed Fusion and High Pressure Die Casting Processes: Indrajeet Katti1; Mark Easton1; Dong Qiu1; Joy Forsmark2; Matthew Barnett3; Matthias Weiss3; 1RMIT University; 2Ford Motor Company; 3Deakin University
Laser powder bed fusion (LPBF) is an upcoming manufacturing technology finding its place in mainstream manufacturing with some benefits over high-pressure die casting (HPDC). This study examines differences in the microstructure and mechanical properties of AlSi10Mg alloy produced by these processes. Plates with different thicknesses were manufactured by both technologies. The HPDC microstructure was much coarser than that seen in LPBF. Differences in eutectic structure, solute silicon levels, and dislocation density were detected. The plate thickness was found to have the opposite effect on the tensile properties of both manufacturing processes. The plate surface hardness of HPDC material was relatively high compared to the core. The opposite trend was observed in the LPBF samples. HPDC samples also showed greater tolerance to localised straining during tight radius bending than the LPBF samples. Substitution of LPBF for HPDC will require careful consideration of ductility requirements.
3:40 PM Break
3:55 PM
Effect of Chemical Composition, Crystallographic Orientation and Processing Parameters on Rapid Solidification in Ni-Al-Mo Single Crystals: Adriana Eres-Castellanos1; Ruben Ochoa1; Chandler Becker1; Kamel Fezzaa2; Jonah Klemm-Toole1; Tresa Pollock3; Amy Clarke1; 1Colorado School of Mines; 2Argonne National Laboratory; 3University of California Santa Barbara
Ni-based alloys are used in aerospace applications because of their high-temperature performance, including excellent corrosion and creep resistance and fatigue performance. Although traditionally processed by casting, additive manufacturing (AM) – e.g. Laser Powder Bed Fusion (LPBF) - enables complex designs to be produced. To understand microstructure development with processing, it is essential to understand the laser-material interactions during melting and solidification. In this study, Ni-Mo-Al alloy single crystals with different Mo and Al contents and crystallographic orientations were subjected to laser spot and track melting under different processing conditions. In-situ synchrotron x-ray imaging was performed at the Advanced Photon Source (Argonne National Laboratory). Solid-liquid interface velocities were directly measured and thermal gradients were modeled. Ex-situ characterization was also performed to understand solidification with processing, crystallographic and chemical composition variations. MURI and AUSMURI Collaborative Research.
4:15 PM
Exploration of Rapidly Solidified β and Near-β Ti Alloys Processed by Two Piston Splat Quenching: Greyson Harvill1; C. Williamson1; Grace Schneider1; Zach Hasenbusch1; Laurentiu Nastac1; Ben Brown2; Andrew Deal2; Luke Brewer1; 1University of Alabama Tuscaloosa; 2Kansas City National Security Campus
This talk will discuss the effects of rapid solidification on the solidification microstructures in multiple β and near-β Ti alloys produced via two piston splat quenching (SQ). Three Ti-Mo binary alloys, Ti5.4wt%Mo, Ti9.6wt%Mo, and Ti12wt%Mo, were produced through arc melting. These alloys and Ti-5553 were rapidly solidified using SQ. Combustion analysis was used to ascertain the concentration of interstitial elements (oxygen and nitrogen) absorbed during the alloy feedstock development and SQ processes. Electron microscopy and x-ray microanalysis are being employed at micro- and nanoscales to characterize splat features including phase composition, grain structure, and chemical homogeneity. The presence of possible secondary phases in these alloys will be correlated with the uptake of interstitial gases and segregation of molybdenum upon rapid solidification. Honeywell Federal Manufacturing & Technologies, LLC operates the Kansas City National Security Campus for the United States Department of Energy / National Nuclear Security Administration under Contract Number DE-NA0002839.
4:35 PM
Use of Magnetic Force to Control Melt Flow and Microstructure during Additive Manufacturing: Xianqiang Fan1; Tristan Fleming2; Samul Clark3; Chu Lun Alex Leung1; Anna Getley1; Sebastian Marussi1; Hongze Wang4; Robert Atwood5; Andrew Kao6; Peter Lee1; 1University College London; 2Queen's University; 3Argonne National Laboratory; 4Shanghai Jiao Tong University; 5Diamond Light Source Ltd; 6University of Greenwich
Melt flow plays a critical role in determining the built quality during additive manufacturing (AM). External forces are usually applied to control melt flow. Thermoelectric (TE) Lorentz forces arise within the AM melt pool when an external magnetic field is applied; these forces offer the potential to control melt flow, removing pores and tailoring microstructures. However, the extent of TE forces, and even their underlying mechanisms, remain unclear. Here, we performed in situ high-speed synchrotron X-ray radiography to reveal the structure of TE force-induced flow using tungsten particle tracers during AM. We found that without an imposed magnetic field, natural convection dominates the flow and hence the tungsten particle trajectories. With a magnetic field applied perpendicular to the scan direction, a TE Lorentz force is induced and it alters the melt pool flow. Whereas when the laser scan direction is reversed, such force is introduced in an opposite direction.
4:55 PM
Grain Boundary Character Distribution in Additively Manufactured Nickel-based Superalloy INC738: Ming Luo1; Xiaozhou Liao2; Simon Ringer2; Sophie Primig1; Nima Haghdadi1; 1UNSW Sydney; 2The University of Sydney
Additive manufacturing (AM) has attracted considerable attention in recent years owing to its unique benefits such as design freedom. Grain boundary engineering (GBE) is a strategy to control the grain boundary network of materials to improve mechanical properties and reduce undesirable intergranular phenomena. The traditional GBE processes, usually composed of thermomechanical treatments, cannot be applied in AM because the builds are usually printed to shape, and therefore cannot be deformed after printing. However, AM instead unlocks a new opportunity to activate GBE, i.e., in-situ GBE, where AM inherent thermal signatures and stresses may trigger GBE. Optimized AM processing parameters that activate in-situ GBE and how the engineered grain boundary network affects mechanical and corrosion properties remain currently unknown for most alloys. To fill this knowledge gap, this study unveils the effect of the scanning strategy on the grain boundary network evolution in electron powder bed fusion printed Ni-based superalloy INC738.