Session Sheet - 2026 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2026): Mechanical and Microstructural Considerations

2026 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2026): Mechanical and Microstructural Considerations
Program Organizers: David Leigh, University of Texas at Austin

Wednesday 8:00 AM
August 5, 2026
Room: Zlotnick Ballroom 6
Location: AT&T Center

8:00 AM
High-Temperature Structural Integrity of Additively Manufactured Inconel 718 for Thermal Management Applications: Zarin Tahsin¹; MohammadBagher Mahtabi²; Aref Yadollahi¹; Scott Thompson³; ¹Purdue University Northwest; ²University of Toledo; ³University of Missouri
    Next-generation compact heat exchangers operate under moderate stress levels while reaching temperatures as high as 1200 °C, placing stringent demands on the structural integrity of additively manufactured nickel superalloys. This study evaluates the tensile, creep, and rupture behavior of laser powder bed fused (L-PBF) Inconel 718 at 900 °C and 1200 °C within this service-relevant regime. Emphasis is placed on the role of build orientation, defect population, and microstructural stability in governing high-temperature performance. Results show that creep response is strongly influenced by orientation-dependent grain structure and defect distribution, with vertically built specimens exhibiting extended rupture life and improved resistance to damage accumulation. The findings demonstrate that creep behavior in this regime is governed by effective load-bearing capacity rather than localized defect severity alone. This work provides a physically grounded basis for assessing structural integrity and supports the qualification of L-PBF Inconel 718 for high-temperature thermal management systems.

8:20 AM
Nanoscale Deformation and Creep Response of LPBF Processed GRX-810 via Instrumented Nanoindentation: Omar Banda¹; Kurtis Watanabe¹; Francisco Medina¹; Patricio Sebastian Rodriguez Beltran¹; Israt Zahan Mim¹; Sohail Mohammed¹; ¹W.M Keck Center for 3D Innovation
    GRX-810 is a NASA nickel-based superalloy designed for extreme-temperature aerospace and hypersonic applications. However, the localized mechanical response at the nanoscale remains poorly understood, particularly under additively manufactured conditions. In this study, room-temperature nanoindentation was employed to investigate the nanoscale mechanical behavior of laser powder bed fusion (LPBF) GRX-810 fabricated under varying process parameters and build orientations. Testing was conducted using a NanoTest Vantage system equipped with a Berkovich indenter to evaluate hardness, elastic modulus, elastic-plastic deformation response, and creep behavior. Specimens were sectioned along multiple planes to assess the build-direction-dependent microstructural anisotropy on localized deformation mechanisms. Load-displacement curves were analyzed using the Oliver-Pharr methodology to quantify mechanical properties and correlate indentation response with LPBF-induced microstructural heterogeneity. The results will provide nanoscale mechanical property datasets for additively manufactured GRX-810 and establish critical insight into orientation-dependent deformation and creep behavior, supporting future qualification and deployment of GRX-810 for aerospace applications.

8:40 AM
Enabling Rapid Qualification of Additively Manufactured Metals Through Location-Specific Mechanical Testing: Prudhvi Raj Pola¹; Olukayode Fatoki²; Santhosh Parupelli²; Salil Desai²; Ranji Vaidyanathan¹; ¹Oklahoma State University; ²North Carolina A&T State University
    Additive manufacturing(AM) offers significant advantages, including design flexibility and reduced production times. However, qualifying AM parts remains challenging due to complex thermal histories that result in heterogeneous microstructures and location-dependent mechanical properties. These complexities render traditional testing methods costly and time intensive. To address these challenges, this study investigates the mechanical behavior of SS 316L components fabricated using the Directed Energy Deposition method. Small tensile specimens, each measuring 3 mm × 1.2 mm × 0.25 mm, were extracted from various regions of an AM part to assess stiffness, yield strength, tensile strength, and strain-to-failure. This methodology provides direct insight into spatial variations in mechanical performance, linked to thermal conditions during manufacturing. Additionally, it enables identification of critical regions and supports the development of a finite element model for predicting part lifespan. Overall, this approach advances understanding of spatial heterogeneity in AM parts and establishes a foundation for improved performance assessment.

9:00 AM
Additively Manufactured GRX-810 Alloy: The Influence of Build Interruptions on Microstructure, Tensile Strength and Fatigue Life: Javier Lares¹; Paul Gradl²; Francisco Medina¹; Colton Katsarelis²; Edel Arrieta¹; ¹W.M. Keck Center for 3D Innovation; ²NASA
    This study investigates the effect of planned build interruptions on the microstructure, tensile behavior, and fatigue performance of laser powder-bed fusion (L-PBF) specimens in the non-heat-treated (NHT) and hot isostatic pressing (HIP) conditions. Samples were evaluated with and without build interruptions, and the results were compared before and after heat treatment. The findings showed that build interruptions did not produce measurable changes in tensile strength, ductility, or fatigue performance. In contrast, HIP-treated specimens exhibited lower strength and higher ductility than NHT samples, which was attributed to grain coarsening during HIP. Fatigue testing revealed a slight improvement in fatigue life for HIP specimens, likely due to the reduction of additive manufacturing defects during processing. Fractography revealed mixed-mode fracture behavior in all samples, along with evidence of pre-existing defects that reactivated during cyclic loading. Overall, planned build interruptions did not significantly affect the mechanical performance of the material.

9:20 AM
Crack Reduction in L-PBF CM247LC using Shell and Core Build Style: Satyendra Kutiyal¹; Ravi Aswathanarayanaswamy¹; Andrew Moore²; Andy Farndell¹; Nick Jones¹; ¹Renishaw Plc; ²Heriot-Watt University
    This study examines crack formation in nickel-based superalloy CM247LC produced by laser powder bed fusion (L-PBF) at 10µm and 20µm layer thicknesses. Reducing to 10µm decreased crack density by 75%, though it increased build time, subsurface regions were crack-free compared to those produced at 20µm. A shell and core approach (20µm core and 10µm shell), improved build rate by 18% and reduced crack by 25% relative to the 20µm layer process. However, remelting at shell-core interfaces caused localised cracking. Scanning Electron Microscopy (SEM) identified ductility dip, solidification, and liquation cracks. Hot Isostatic Pressing (HIP) minimised cracks, and further heat treatments promoted γ′ precipitation. Heat-treated samples exhibited hardness of 452 ± 10 HV0.5, room temperature tensile strength of 1181 ± 56 MPa, and elongation of 11 ± 1%. SEM fracture analysis revealed grain-boundary cracking and brittle fracture. Overall, the shell and core approach enables HIP-ready L-PBF parts without compromising tensile properties.

9:40 AM Break

10:00 AM
Grain Morphology and Aging Response of Aheadd® CP1 Processed by Directed Energy Deposition.: Elaina Kwarteng¹; Jakob Hamilton¹; ¹Iowa State University
     Additive manufacturing makes aluminum alloys attractive for aerospace and automotive parts because they can be lightweight, complex, and material-efficient. However, cracking and unstable solidification are still major barriers to broader use. In this study, Aheadd® CP1, an Al-Fe-Zr alloy developed for additive manufacturing, was deposited onto AA6061 substrates to evaluate the effects of laser power, scanning speed, and substrate preheating on build quality and microstructural development. Without substrate preheating, the deposits showed a narrow range of process parameters that produced acceptable deposition quality. Surface morphology and resultant deposition geometry are reliant on the applied laser energy density. Higher power improved layer continuity and melt-pool stability, while lower power produced a rougher and less uniform surface. These preliminary results suggest that CP1 can be processed successfully within the selected DED window. Ongoing characterization will further examine phase evolution and strengthening mechanisms and help establish process-structure-property relationships for crack-resistant aluminum additive manufacturing.

10:20 AM
Microstructure–Corrosion Relationships in LPBF 316L Stainless Steel: Joshua Owen¹; Joshua Magiera²; Finlay Spence¹; Robert Kay¹; Paolo Actis¹; Xiangdong Xu²; Dimitrios Valavanis²; Patrick Unwin²; ¹University of Leeds; ²University of Warwick
    Corrosion behaviour is an increasing concern for metal alloys produced by additive manufacturing (AM) as their industrial adoption expands. AM alloys often exhibit corrosion responses distinct from conventionally processed materials due to process‑induced microstructural heterogeneity, raising questions about long term performance in corrosion‑critical applications. Localised corrosion, particularly pitting, is strongly influenced by microstructural features, yet conventional bulk electrochemical methods can obscure their individual contributions. This challenge is evident in AM alloys, where microstructural effects are frequently inferred from macroscale testing. Here, the corrosion behaviour of wrought 316L stainless steel is compared with an equivalent produced by laser powder bed fusion (LPBF) in 5 mM sulphuric acid. Macroscale electrochemical techniques are complemented by scanning electrochemical cell microscopy (SECCM) and surface analytical techniques. Manganese sulphide (MnS) inclusions were detected in wrought 316L and linked to localised current hotspots, while their absence in AM 316L led to a more uniform passive response.

10:40 AM
Laser Welding of Additively Manufactured Inconel 718 Double-Walled Cooling Channels: Jimena Coello¹; Patricio Sebastian Rodriguez Beltran¹; Kurtis Watanabe¹; Colton Katsarelis²; Paul Gradl²; Marco Opitz³; Francisco Medina¹; ¹W.M. Keck Center for 3D Innovation, Department of Aerospace and Mechanical Engineering, College of Engineering, The University of Texas at El Paso; ²NASA Marshall Space Flight Center; ³TRUMPF Inc
    Additive manufacturing (AM) enables the production of complex double-walled cooling channel geometries for aerospace applications that are difficult to fabricate using conventional methods. This research focuses on the laser welding of AM double-walled cooling channels fabricated in Inconel 718 using Laser-Powder Bed Fusion (L-PBF) for heat exchanger applications. The objective is to evaluate the feasibility of single-sided laser welding as a post-processing method to seal and join these structures while maintaining leak-free joints across both the ribs and channel walls, despite their significantly different thicknesses. Evaluation of the welded samples includes characterization of the weld region through microstructural analysis, microhardness testing, and geometric inspection to assess weld quality and joining behavior.