Task Progress:
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Project Overview
This research provides quantitative correlations between solidification and flow characteristics, processing conditions, microstructure, and porosity for solder joints produced in terrestrial vs. microgravity conditions (onboard the International Space Station (ISS)). Furthermore, this project focuses on analyzing solder joint properties under extreme conditions of elevated and cryogenic temperatures in space. Soldering is the predominant method used to create electrical/mechanical joints and mechanical/pressure joints and is typically a rapid process in which the solder material is molten for only a few seconds. Solder joint porosity is a common but undesirable feature naturally arising from the use of fluxes and is more insidious in soldering joints formed under microgravity conditions. Under the presence of gravity, voids and bubbles are removed from the solder joints due to presence of buoyancy force and vigorous liquid solder mixing. In the absence of gravity, fluid motion is greatly reduced, driven mainly by solidification volume change, thermally induced density gradients, and Marangoni effects. With slower mixing, voids and bubbles are not swept away and become entrapped in the interior of the solder joint upon solidification. This entrapped porosity dramatically degrades the thermal and electrical properties of the solder and severely reduces the mechanical integrity of the joint. Therefore, as part of the ongoing endeavors to establish an electronics and mechanical joint repair capability for extended space missions, this project seeks to advance the current understanding of fundamental mechanisms, phenomenology, and process conditions that govern the integrity and performance of solder joints produced in terrestrial vs. reduced gravity environments. Additionally, solder joints in the space environment are subjected to large temperature variations such as – 120 ºC to +25 ºC for the Mars missions, and – 157 ºC to +121 ºC outside ISS. However, as deep space exploration missions become longer and more distant, the solder and other metal joints' current reliability is inadequate for the harsh conditions they encounter.
This project focused on the following objectives to address the reliability of solder joints in space: 1) Characterizing the effects of the lack of Earth's natural convective flow and buoyancy on solder-joint formation onboard the ISS using the 40Pb-60Sn solders from the In-Space Soldering Investigation (ISSI), 2) Investigating the effects of elevated and cryogenic temperature conditions in space on solder properties. Considering a range of potential applications and materials, three solder alloys were investigated, including the ISSI lead-based (40Pb-60Sn) solders, off-eutectic 50Pb-50Sn solders, and lead-free (95.5Sn-3.8Ag-0.7Cu) solders, which had recently shown promise for high-performance joint applications due to their good thermal and electrical conductivities, as well as excellent corrosion and fatigue resistance.
Our team conducted the microstructural characterization of four microgravity-processed solders from the ISSI study, one ISSI terrestrial solder, and a third set of freshly made terrestrial 40wt%Pb-60wt%Sn solder to demonstrate the effects of the absence of buoyancy and natural convection on void formation in microgravity. The effect of void-induced Marangoni convection on the solder microstructure was demonstrated using the microgravity wire-feed solder. Additionally, the micromechanical response of solders processed in terrestrial and microgravity environments was investigated under extreme elevated and cryogenic temperature conditions (ranging from –157ºC to +121ºC, as experienced outside the ISS). Under cryogenic conditions, the study investigated the impact of the β-to-α phase transformation in Sn below 13ºC, including associated volume changes, internal stress development, and the ductile-to-brittle transition observed in various Sn-based solder alloys. At room temperature, the effects of accelerated aging on the solders' microstructure and mechanical properties were explored.
Major Goals/Objectives
The major focus of this project was to elucidate the fundamental mechanisms, phenomenology, and process conditions that govern the integrity and performance of solder joints produced in terrestrial vs. reduced gravity environments, such as the microgravity conditions onboard the International Space Station (ISS). The primary objectives included advancing the current qualitative understanding of porosity formation and persistence in solder joints into the realm of alloy/process-specific quantitative description and prediction and evaluating the influence of elevated and cryogenic temperatures on the microstructural and mechanical properties of solder joints, with emphasis on Sn-based alloys.
Leveraging solder samples from the In-Space Soldering Investigation (ISSI) and other non-ISSI compositions, the project employed a combination of advanced experimental techniques and computational modeling. These approaches were designed to characterize the impacts of void-induced microstructural variations, extreme thermal cycling, and phase transformations, addressing critical reliability challenges for soldering in space environments. The project aimed to address critical scientific gaps related to solder joint reliability in the unique microgravity and thermal conditions of space, with the ultimate goal of providing quantitative insights for designing more robust soldering techniques. While this proposal focused on understanding the fundamental phenomena, it also laid a solid scientific foundation for future advancements in space fabrication and repair technologies. This work contributes directly to NASA’s goals of improving in-space manufacturing and repair capabilities while establishing a strong foundation for future innovations in soldering processes tailored to the harsh conditions of deep-space exploration.
Accomplishments under Goals
The research program achieved several significant accomplishments in advancing the understanding of solder behavior in terrestrial vs. microgravity environments, with a focus on enhancing their reliability for space applications. This study analyzed near eutectic 40Pb-60Sn solder samples from the In-Space Soldering Investigation (ISSI), conducted in microgravity aboard the International Space Station (ISS) and under terrestrial conditions at NASA Marshall. The ISS experiments were performed by taking pieces of silver-coated copper wire and bending and twisting them into multiple test coupon configurations. The selected lengths of 40wt%Pb-60wt%Sn wire were cut and 1) wrapped around the test coupons and melted using the soldering iron – Wire wrap solder and 2) fed on the similar test coupons that were heated by the soldering iron – Wire feed solder (Fig.1). The ground experiments involved conductively melting 10 cm lengths of 40Pb-60Sn (3.3 wt% rosin flux) solder onto a loop turned into the silver coated copper wire. For more details about the ISSI experiments, refer to: Background: In-Space Soldering Investigation (ISSI 2003-04) section in this report. Additionally, near-eutectic 40Pb-60Sn, off-eutectic 50Pb-50Sn, and 95.5Sn-3.8Ag-0.7Cu terrestrial solder samples (named ISU terrestrial) were prepared and examined in Dr. Pathak’s research lab at Iowa State University, Ames. For a detailed list of samples and tasks, refer to the Outline of Executive Summary of this report. Key accomplishments include:
Accomplishments from the study on near-eutectic 40Pb-60Sn solder (microgravity and terrestrial):
Samples analyzed: ISSI microgravity 40Pb-60Sn wire warp solder (Microgravity test 2 sample 4, 5 and 10) ISSI microgravity 40Pb-60Sn wire feed solder (Microgravity test 4 sample 16 – MT4S16) ISSI terrestrial 40Pb-60Sn wire feed solder ISU Terrestrial 40Pb-60Sn wire wrap and wire feed solder (prepared in Dr. Pathak’s lab) ISU Terrestrial 40Pb-60Sn Reflow Spreading solder (prepared in Dr. Pathak’s lab) • Demonstrated the effect of natural convection and buoyancy on void size in 40Pb-60Sn solder formed under microgravity vs. terrestrial conditions using non-destructive 3-D tomography. Results demonstrated that the occurrence of larger voids (as large as 1 mm in diameter) only happens in microgravity conditions. • Developed a quantitative framework for describing and predicting porosity formation and persistence in 40Pb-60Sn solder under microgravity vs. terrestrial conditions, addressing the role of reduced buoyancy-driven convection and flux volatilization. ISSI microgravity wire wrap 40Pb-60Sn solder had ~13× more voids than ISSI terrestrial 40Pb-60Sn solder, while ISSI microgravity wire feed 40Pb-60Sn solder had 4× more voids than ISSI wire wrap 40Pb-60Sn solder. • Studied the effect of Marangoni convection in microgravity 40Pb-60Sn solder under the presence of a large free surface (large void, greater than 1 mm) on solder microstructure (primary dendrite and small void accumulation). The average Pb-particle size near the hot site was 6.1 ± 5 µm and near the cold site (expected to be at a lower temperature than the hot site) was 4.8 ± 5 µm which was caused by the differential cooling rate in the colder and hot sites and accumulation of Pb-rich dendrite in the hot region. • Quantified the effect of microstructure, influenced by void-induced Marangoni convection, on microgravity solder properties. We demonstrated that Inhomogeneity (accumulation of Pb-rich dendrites at the solder joint) resulting from Marangoni flow caused lower strength (hardness ~ 0.11 GPa) of the solder at the hot site than at the colder site (hardness ~ 0.15 GPa). • The aging study on terrestrial 40Pb-60Sn solder showed a hardness decrease from 0.19 GPa on day 1 to 0.16 GPa on day 483, accompanied by Pb particle growth from 1.28 μm to 2.45 μm over the same period. • Investigated the β-Sn to α-Sn phase transformation below 13°C on pure Sn single crystal and terrestrial 40Pb-60Sn solder using high-throughput spherical nanoindentation, elucidating the effect of associated volume changes and internal stresses on mechanical performance in cryogenic environments. • Investigated the effects of ductile to brittle transition on terrestrial 40Pb-60Sn solder properties via in-situ SEM micropillar compressions. Plastic strain at instability under compression in 40Pb-60Sn decreased from ɛ = 0.109 at RT to ɛ = 0.06 below -85°C, suggesting a ductile-to-brittle transition near this temperature.
Accomplishments from the study of terrestrial off-eutectic 50Pb-50Sn solder:
Sample analyzed: ISU Terrestrial 50Pb-50Sn solder sample 1 to 3 (prepared in Dr. Pathak’s lab) • Aging study on terrestrial 50Pb-50Sn demonstrated that the hardness dropped from 0.18 to 0.14 GPa, and Pb particle size grew from 0.45 to 0.8 μm over 89 days. Accomplishments from the study on terrestrial 95.5Sn-3.8Ag-0.7Cu solder: Sample analyzed: ISU Terrestrial 95.5Sn-3.8Ag-0.7Cu solder sample 1 (prepared in Dr. Pathak’s lab) • In-Situ SEM micro-pillar compression on ISU terrestrial 95.5Sn-3.8Ag-0.7Cu solder demonstrated that plastic strain at instability under compression dropped from ɛ = 0.06 at RT to ɛ = 0.03 at -85°C and lower temperatures, signaling a ductile-to-brittle transition around this temperature. • The deformation behavior was correlated with microstructure across all temperatures. Group 3 (eutectic mixture of Ag3Sn + Sn) demonstrated a sharp decrease in the plastic strain at instability as the temperature drops below room temperature (RT), probably caused by the high fraction of the Ag₃Sn intermetallic phase that significantly influences the mechanical response. At cryogenic temperatures, Ag₃Sn is much stiffer and more brittle than the Sn-rich phase. As temperature decreases, deformation becomes increasingly localized at phase boundaries, reducing plasticity and accelerating the ductile-to-brittle transition. • In contrast, Group 2a (eutectic Ag3Sn + Sn + Sn-rich dendrite) showed a gradual decrease in plastic strain with decreasing temperature, as its balanced mix of Sn-rich and eutectic phases allowed for some residual plasticity, unlike the sudden drop observed in Group 3. Group 2b (Cu5Sn6 + group 2a) exhibited the lowest plastic strain across all temperatures due to the presence of Cu₆Sn₅ intermetallic compounds, which increased stiffness and restricted plastic deformation, leading to early instability.
Objectives and Outcomes Year 1: Sample analyzed: • ISSI M 40Pb-60Sn Test 2 Sample 4 • ISSI M 40Pb-60Sn Test 4 Sample 16 • ISSI 40Pb-60Sn Terrestrial Sample 2 • ISSI 40Pb-60Sn Terrestrial Sample 3 • ISU 40Pb-60Sn Terrestrial Sample 1
The first year of this project was focused on studying the near-eutectic 40Pb-60Sn (terrestrial and microgravity) and off-eutectic 50Pb-50Sn (terrestrial) solder compositions. This study focused on understanding the role of reduced buoyancy forces and natural convection in void formation and microstructural inhomogeneity in 40Pb-60Sn solder under microgravity conditions, alongside the effects of room temperature aging on ISSI microgravity 40Pb-60Sn, terrestrial 40Pb-60Sn and terrestrial 50Pb-50Sn solder properties. Additionally, the study aimed to quantify the influence of Marangoni flow and thermal convection on void dynamics and phase segregation in ISSI microgravity 40Pb-60Sn solder. The study demonstrated that microgravity conditions significantly increased void fraction (ISSI microgravity wire wrap solder had ~13× more voids than terrestrial solder) and size in solder joints due to the absence of buoyancy-driven convection, with Marangoni flow contributing to void and Pb-rich dendrite accumulation in high-temperature regions. Mechanical testing revealed ductile-to-brittle transitions in ISU terrestrial 40Pb-60 Sn solder under cryogenic conditions at temperatures at and below -85 oC, while aging studies highlighted grain coarsening (Pb particle size =1.28 μm on day 1 to 2.45 μm on day 483) and hardness reduction (0.19 GPa on day 1 to 0.15 GPa on day 483) in 40Pb-60Sn solder alloys. Please see the year one report for further details of this section.
Year 2:
Sample analyzed: ISSI M 40Pb-60Sn Test 2 Sample 10 ISSI M 40Pb-60Sn Test 4 Sample 16 ISU 40Pb-60Sn Terrestrial Sample 3 ISU 50Pb-50Sn Terrestrial Samples 1, 2, and 3 ISU 95.5Sn-3.8Ag-0.7Cu Terrestrial Sample 1
The second year of this project focused on 1) quantifying the effects of void-induced Marangoni convection and thermal gradients on ISSI microgravity 40Pb-60Sn solder strength and 2) evaluating the influence of elevated and cryogenic temperatures on Sn-based terrestrial solders (40Pb-60Sn, 50Pb-50Sn and 95.5Sn-3.8Ag-0.7Cu) properties, including ductile-to-brittle transition and phase transformations.
The study revealed that void-induced Marangoni convection in microgravity significantly reduces solder hardness near high-temperature regions due to the localized accumulation of softer Pb-rich phases, highlighting the critical need to develop soldering processes that mitigate microstructural inconsistencies to ensure the structural integrity of solder joints in space environments. Cryogenic temperature studies on ISU terrestrial 40Pb-60Sn solder using high throughput spherical nanoindentation stress-strain analysis revealed that 40Pb-60Sn solder exhibits increased yield strength from 0.18 GPa (0.05 offset yield strength) at RT to 0.32 GPa at -120°C, while pure Sn shows unusual softening at -120°C, likely due to the β-to-α phase transformation, emphasizing the need for alloy-specific reliability assessments under extreme conditions. The micro-pillar compression experiments revealed a significant ductile-to-brittle transition in ISU terrestrial 40Pb-60Sn solder below -85°C, characterized by decreased plastic strain at instability from 0.109 at RT to 0.062 at -85°C and deformation concentrated along Pb-rich and Sn-rich phase boundaries. Micropillar compression experiments on ISU terrestrial 95.5Sn-3.8Ag-0.7Cu solder at cryogenic temperatures revealed a significant increase in stress at instability which changed from 78 MPa at RT to 153 MPa at -145°C, with a noticeable saturation in instability stress below -85°C and a reduction in the plastic strain at instability (from 0.06 at RT to 0.03 at -85°C ), primarily attributed to a ductile-to-brittle transition. Deformation mechanisms in 95.5Sn-3.8Ag-0.7Cu varied with temperature and percentage of various phases in the different pillars, with deformation predominantly progressing along Sn-rich dendrites at -40°C, shifting to eutectic and intermetallic interfaces below -85°C, highlighting the critical role of phase boundaries in cryogenic mechanical behavior.
Dissemination
Summary of Technical Dissemination: Research undertaken and supported by this grant was completed at Iowa State University Ames by graduate and undergraduate researchers. Scientific products were finalized and disseminated through professional society technical presentations, invited academic, and technical seminars, and student posters at several academic and society events. While most technical presentations were given by the PIs, graduate researchers supported by this project had many opportunities for presentation and publishing. At the time of this final report’s submission, four peer-reviewed publications are in the final stages of preparation for submission. Further, outcomes from research activities in this program were included as 1 invited talk and 12 conference talks, including graduate student Manish Kumar’s one PhD dissertation and one more invited talk to be given after the completion of this grant.
Products:
2025 • Kumar M, Napolitano R, Pathak S, “Reliability of Terrestrial vs. Microgravity Solders under Extreme Elevated and Cryo Temperatures for Deep Space Exploration” , The Minerals, Metals and Materials Society (TMS), , Las Vagas, NV March 23–27, 2025. 2024 • Kumar M, Napolitano R, Pathak S, “Reliability of Terrestrial vs. Microgravity Solders under Extreme Elevated and Cryo Temperatures for Deep Space Exploration” Annual Meeting of the American Society for Gravitational and Space Research (ASGSR), San Juan, Puerto Rico December 3-7, 2024. • Kumar M, Napolitano R, Pathak S, “Reliability of Terrestrial vs. Microgravity Solders under Extreme Elevated and Cryo Temperatures for Deep Space Exploration” International Space Station Research & Development Conference (ISSRDC), Boston, Massachusetts, July 29-August 1, 2024. • Invited: Kumar M, Napolitano R, Pathak S, “Structure and Properties of Terrestrial vs. Microgravity Solders under Extreme Conditions of Elevated and Cryo Temperatures,” Virtual NASA PSI User Meeting, March 2024. • Kumar M, Napolitano R, Pathak S, “Structure and Properties of Terrestrial vs. Microgravity Solders under Extreme Conditions of Elevated and Cryo Temperatures,” The Minerals, Metals and Materials Society (TMS), Orlando, Florida, March 3-7, 2024. • Kumar M, Napolitano R, Pathak S, “Structure and Properties of Terrestrial vs. Microgravity Solders under Extreme Conditions of Elevated and Cryo Temperatures,” Center for Advanced Non-Ferrous Structural Alloys IRB Review Meeting, Iowa State University, Ames, Iowa, October 22-23, 2024.
2023 • Kumar M, Napolitano R, Pathak S, “Structure and Properties of Terrestrial vs. Microgravity Solders under Extreme Conditions of Elevated and Cryo Temperatures,” Annual Meeting of the American Society for Gravitational and Space Research (ASGSR), Washington, D.C, November 14-18, 2023. • Hellyer S, Ogden C, Kumar M, Napolitano R, Pathak S, “Studying the Effects of Aging on the Structure and Properties of Off-Eutectic 50wt%Pb-50wt%Sn Solder Joints for In-Space Applications,” Annual Meeting of the American Society for Gravitational and Space Research (ASGSR), Washington, D.C, November 14-18, 2023. • Kumar M, Napolitano R, Pathak S, “Structure and Properties of the Terrestrial vs. Microgravity Solders under Extreme Conditions of Elevated and Cryo Temperatures,” International Space Station Research & Development Conference (ISSRDC), Seattle, Washington, July 31-August 3, 2023. • Hellyer S, Ogden C, Kumar M, Napolitano R, Pathak S, “Studying the Effects of Aging on the Structure and Properties of Off-Eutectic 50wt%Pb-50wt%Sn Solder Joints for In-Space Applications,” National Conference on Undergraduate Research (NCUR), Eau Claire, Wisconsin, April 13-15, 2023. • Kumar M, Jacob K, Napolitano R, Pathak S, “Structure and Properties of Pb-Sn Solders Produced in Terrestrial vs. Microgravity Environments,” Center for Advanced Non-Ferrous Structural Alloys IRB Review Meeting, Colorado School of Mines, Golden, Colorado, September 27-28, 2023. • Kumar M, Napolitano R, Pathak S, “Structure and Properties of Solder Joints Produced in Terrestrial and Microgravity Conditions,” The Minerals, Metals and Materials Society (TMS), San Diego, California March 19-23, 2023. • Kamp J, Madison N, Kumar M, Pathak S, “Structure and Properties of Pb-Sn and Pb-Free 95.5Sn-3.8Ag-0.7Cu Solders Produced in Terrestrial Environment,” ISU Symposium on Undergraduate Research and Creative Expression, Ames, Iowa, April 20, 2023.
Scientific Manuscripts under preparation • Kumar, M., Azizi, G., Napolitano, R., Zaeem, M., Pathak, S., "Effect of Aging on Structure and Properties of the 40Pb-60Sn Solders for In-Space Applications." • Kumar, M., Napolitano, R., Pathak, S., "Structure and Properties of Solder Joints Produced in Terrestrial vs. Microgravity Conditions." • Kumar, M., Hellyer, S., Ogden, C., Kamp, J., Napolitano, M., Pathak, S., "Effect of Aging on Structure and Properties of the 50Pb-50Sn Solders for In-Space Applications." • Kumar, M., Napolitano, R., Pathak, S., "Solder Joint Reliability under Extremes of Elevated and Cryogenic Temperatures Experienced during Deep Space Exploration."
Honors and Awards
2024 • December 2024: Graduate student Manish Kumar’s research was prominently featured in NASA's 2025 Science Calendar for the month of November. Hear Dr. Fox’s thoughts on our research during the ASGSR conference: https://iastate.box.com/s/gov6zufb17rvnleoua075k8n4nf1y4dw Link to download the high-resolution NASA Science calendar: https://science.nasa.gov/multimedia/2025-nasa-science-planning-guide/?utm_source=cal&utm_medium=print&utm_id=2025guide • March 2024: Undergraduate researcher Soren Hellyer was awarded the TMS Acta Materialia Scholarship-2024 • February 2024: Manish Kumar was awarded the Brown Graduate Fellowship Award ($10,000) – Recognized by the Office of the Vice President for Research at Iowa State University for exceptional achievements and contributions to space science. • January 2024: TMS student travel award ($300) - to help defray the costs of attendance at the Mineral, Metals and Materials Society annual meeting (TMS-2024).
2023 • November 2023: Manish Kumar was awarded ASGSR Student Travel Award ($500) to help defray the costs of attendance at the American Society for Gravitational and Space Research (ASGSR-2023) conference. • August 2023: Manish Kumar was awarded Wayne G. Basler Scholarship ($5000) for 2023 in Materials Science and Engineering at Iowa State University • June 2023: Sigma Xi Grants ($1000) in Aid of Research 2023 - Sigma Xi’s Committee on Grants-in-Aid of Research has approved Manish’s research grant proposal titled” Solder Joints Under Extreme Conditions of Temperature and High Strain-rate for In-Space Applications,” submitted for the March 15, 2023 application cycle. Among the 97 recipients of the Sigma Xi award this year, only seven were granted in the field of Engineering, and Manish was one of those seven recipients. You can read the press release about the recipients: https://www.sigmaxi.org/programs/grants-in-aid-of-research/grant-recipients • April 2023: Noah Madison was awarded the Outstanding First-Year Honors Mentor Program (FHMP) Scholar Award – 2023 • March 2023: Joshua Kamp and Noah Madison were awarded First-Year Honors Mentor Program Grant-2023 • February 2023: Dr. Pathak was awarded the 2023 Iowa NASA EPSCoR Partnership Development Travel Grant ($7500) to initiate a new research collaboration on soldering under extreme temperature conditions with NASA International Space Station (ISS) implementation partners and scientists at NASA Marshall • January 2023: Soren Hellyer and Caleb M Ogden received the NASA – Iowa Space Grant Consortium Award ($5000). This award was intended to provide experiences to undergraduates that promote skills for STEM careers through hands-on activities (Project mentors: Manish Kumar, Dr. Sid Pathak)
Training Opportunity
Graduate researchers who were involved in this project (PhD student at ISU - Mr. Manish Kumar) got the opportunity to do the following training and experiences: • Received training at the Sensitive Instrument Facility (SIF) at Ames Laboratory, including SEM/FIB, EBSD, and in-situ SEM Hysitron PI-85 Picoindenter to perform both in-situ nanoindentation and micropillar compression. • Visited Bruker Inc., Eden Prairie, MN, to perform In-Situ SEM Nanoindentation experiments at cryo temperature and received training on TI-980 Triboindenter. • Received training on Micro-EDM machine to fabricate the micro-pillars and micro-tensile geometries. • Traveled to the Advanced Photon Source in Argonne National Laboratory for Non-destructive 3-D tomography experiments. • Traveled to the University of Wisconsin, Madison to fabricate the tensile gripper using the Plasma FIB.
Undergraduate students (Soren Hellyer, Caleb Ogden, Noah Madison, Joshua Kamp) were trained on the automatic mechanical polisher (Tegramin-25), microstructural characterization tool (Optical microscope and SEM), and nano-mechanical testing tool (TI-950 nanoindenter).
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Conference Materials (Downloadable)
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Kamp J, Madison N, Kumar M, Pathak S. "Structure and properties of Pb-Sn and Pb-Free Sn-Ag-Cu solders produced in terrestrial environment." SU Symposium on Undergraduate Research and Creative Expression, Ames, Iowa, April 20, 2023. , Apr-2023 NCUR_2023_Hellyer_Ogden_23_3_23_Final.pdf (3,778 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Structure and properties of solder joints produced in terrestrial and microgravity conditions." The Minerals, Metals and Materials Society (TMS), San Diego, California, March 19-23, 2023. , Mar-2023 2023 ISSRDC_Poster_Manish Kumar 2023-07-24.pdf (3,352 KB)
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Conference Materials (Downloadable)
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Kumar M, Jacob K, Napolitano R, Pathak S. "Structure and properties of Pb-Sn solders produced in terrestrial vs. microgravity environments." Center for Advanced Non-Ferrous Structural Alloys IRB Review Meeting, Colorado School of Mines, Golden, Colorado, September 27-28, 2023. , Sep-2023 2023 CANFSA_Poster_Manish Kumar 2023-03-28.pdf (2,545 KB)
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Conference Materials (Downloadable)
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Hellyer S, Ogden C, Kumar M, Napolitano R, Pathak S. "Studying the effects of aging on the structure and properties of off-eutectic 50wt%Pb-50wt%Sn solder joints for in-space applications." National Conference on Undergraduate Research (NCUR), Eau Claire, Wisconsin, April 13-15, 2023. , Apr-2023 NCUR_2023_Hellyer_Ogden_23_3_23_Final.pdf (3,778 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Structure and properties of the terrestrial vs. microgravity solders under extreme conditions of elevated and cryo temperatures." International Space Station Research & Development Conference (ISSRDC), Seattle, Washington, July 31-August 3, 2023. , Jul-2023 2023 ISSRDC_Poster_Manish Kumar 2023-07-24.pdf (3,352 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Structure and properties of terrestrial vs. microgravity solders under extreme conditions of elevated and cryo temperatures." 39th Annual Meeting of the American Society for Gravitational and Space Research, Washington, DC, November 13-18, 2023. , Nov-2023 ASGSR_Manish Kumar_NASA Soldering_2023-11-16 v3.pdf (4,128 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Structure and properties of terrestrial vs. microgravity solders under extreme conditions of elevated and cryo temperatures." Center for Advanced Non-Ferrous Structural Alloys IRB Review Meeting, Iowa State University, Ames, Iowa, October 22-23, 2024. , Oct-2024 CANFSA_2024_Soldering 2024-10-21 v2.pdf (4,914 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Structure and properties of terrestrial vs. microgravity solders under extreme conditions of elevated and cryo temperatures." The Minerals, Metals and Materials Society (TMS), Orlando, Florida, March 3-7, 2024. , Mar-2024 TMS_Manish Kumar_NASA Soldering_2024-03-02 v3.pdf (4,908 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Structure and properties of terrestrial vs. microgravity solders under extreme conditions of elevated and cryo temperatures." NASA Physical Sciences Informatics (PSI) User Meeting, Virtual, March 14, 2024. , Mar-2024 Soldering_NASA PSI User meeting 2024-03-13 SP - MK v2.pdf (7,821 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Reliability of terrestrial vs. microgravity solders under extreme elevated and cryo temperatures for deep space exploration." International Space Station Research & Development Conference (ISSRDC), Boston, Massachusetts, July 29-August 1, 2024. , Jul-2024 ISSRDC_2024_Soldering 2024-07-22 MK V3.pdf (4,841 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Reliability of terrestrial vs. microgravity solders under extreme elevated and cryo temperatures for deep space exploration." 40th Annual Meeting of the American Society for Gravitational and Space Research, San Juan, Puerto Rico, December 3-7, 2024. , Dec-2024 ASGSR_2024_Soldering 2024-12-03 - v4.pdf (3,975 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Video file." ASGSR 2024 (slide 5). ASGSR 2023 (slide 12). CANFSA 2024 (Slide 15). ISSRDC 2024 (Slide 15).TMS 2024 (Slide 12). NASA PSI User meeting (Slide 25). , Jan-2025 -120_40Pb-60Sn_Pillar 12 15 sec.mp4 (9,027 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Video file." ASGSR 2024 (slide 12). , Dec-2024 -145_Sn-Ag-Cu Pillar 16 TIF Time combined 16 sec.mp4 (18,873 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Video file." ASGSR 2024 (slide 7). CANFSA 2024 (Slide 17). ISSRDC 2024 (Slide 17). , Dec-2024 Full soldering assembly Tec-Masters Nanorack v6.mp4 (47,922 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Video file." ASGSR 2024 (slide 12). , Dec-2024 ISSI Wire Feed_NASA PSI database.mp4 (59,870 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Video file." ASGSR 2023 (slide 3, 5). CANFSA 2024 (Slide 7). ISSRDC 2024 (Slide 6). TMS 2024 (Slide 7). NASA PSI User meeting (Slide 13). , Dec-2024 ISSI Wire Wrap_NASA PSI database.mp4 (46,522 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Video file." ASGSR 2023 (slide 3). CANFSA 2024 (Slide 6). ISSRDC 2024 (Slide 6). NASA PSI User meeting (Slide 11). , Dec-2024 Micro-CT_Terrestrial 40Pb_60Sn_Sample1 (Dentrites and Voids) 01.mp4 (4,121 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Video file." ASGSR 2024 (slide 5). CANFSA 2024 (Slide 15). ISSRDC 2024 (Slide 15). NASA PSI User meeting (Slide 25).
, Dec-2024 RT_40Pb-60Sn_Pillar 13 15 Sec.mp4 (11,936 KB)
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Conference Materials (Downloadable)
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Kumar M, Napolitano R, Pathak S. "Video file." ASGSR 2024 (slide 7). CANFSA 2024 (Slide 17). ISSRDC 2024 (Slide 17). , Dec-2024 RT_Sn-Ag-Cu_Pillar 3 TIF Time Combined 13 sec.mp4 (8,327 KB)
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Journal/Magazine covers
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Kumar M, Pathak S. "Cover in the journal Gravitational and Space Research. Description: Earth rotating around sun or a void inside microgravity solder. Graduate student Manish Kumar’s research work was featured on the 2022 cover of Gravitational and Space Research (GSR). " https://sciendo.com/issue/GSR , Nov-2021
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Significant Media Coverage
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Kumar M, Pathak S. "Solar system parallelism inside a solder bead. Graduate student Manish Kumar’s research was featured in NASA's 2025 Science Calendar for the month of November. " NASA's 2025 Science Calendar. https://science.nasa.gov/multimedia/2025-nasa-science-planning-guide/#science-images , Dec-2024
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Significant Media Coverage
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Fox N. "Dr. Nicola Fox highlights the research of S. Pathak and graduate student M. Kumar." 40th Annual Meeting of the American Society for Gravitational and Space Research, San Juan, Puerto Rico, December 3-7, 2024. https://iastate.box.com/s/gov6zufb17rvnleoua075k8n4nf1y4dw , Dec-2024
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