Center for Advanced Materials (CAM)

HRL has developed an effective and efficient cooling block for thermal management of high-power GPUs. By utilizing additively manufactured flow manifolds to combine pressure loss reduction features (<6 psi) and coupling to copper microchannel finplates we demonstrate >1 kW cooling with low specific thermal resistance (<25 mm2K/W) and low pump input power. Aligned graphite finplates are being developed for even better thermal performance (<10 mm2K/W). This single-phase cooling solution leverages existing data center liquid cooling hardware (pumps, coolant delivery units, manifolds) to yield a simple drop-in replacement or upgrade for data centers. Its performance enables high power racks (0.5 - 1 MW) and dry cooling even at hot, humid sites.

Press Release: https://www.hrl.com/news/2023/08/01/hrl-project-will-keep-data-cool-with-far-less-energy

The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency- Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0001754. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

As microelectronic devices decrease in size and increase in performance, heat removal becomes a limiting factor. The current push towards 3D Heterogeneously Integrated (3DHI) microsystems intensifies the thermal management challenges due to embedded hot spots, numerous thermal interfaces, low thermal conductivity of packaging materials, limited heat extraction pathways, and minimal area for cooling. Under the DARPA Minitherms3D program, HRL is leading a team to develop a complete thermal management solution for a high-power (>6.8 kW total dissipated) 5-active-tier 3D heterogeneously integrated chip stack for future application to radio frequency (RF) phased-arrays. Our approach integrates top- and backside microchannel cooling, electroplated copper-diamond composite heat spreaders, and aerogel thermal isolation. HRL's thermal management solutions for advanced semiconductor packaging could enable more compact and powerful phased arrays for RF communication and radar applications and overcome limitations in the growth of high-performance computing for artificial intelligence and machine learning.

Press Release: https://www.hrl.com/news/2025/03/12/hrl-to-present-superior-cooling-system-for-stacks-of-computer-chips-at-gomactech

Conference Presentations:

C. Roper et al. "PHased ARray with INnovative HEterogeneously Integrated Thermal Solution (PHARINHEITS)", Government Microcircuit Applications & Critical Technology Conference (GOMACTech) 2025

R. Keech et al. "Custom Si Chip Fabrication to Benchmark Local Temperatures within 3D Heterogeneously Integrated Stacks", Government Microcircuit Applications & Critical Technology Conference (GOMACTech) 2025

This material is based upon work supported by the DARPA under Contract No. HR0011-24-C-0305. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NIWC and DARPA.

HRL pioneered the use of functional particle additives during additive manufacturing to engineer the solidification process, form dispersoids and modify composition. By adding small amounts of functional particles such as zirconium hydride to the feedstock powder, the solidification mechanism can be manipulated to overcome challenges with fast melt pool cooling rates and large thermal gradients during laser or electron beam based additive manufacturing. Using this approach HRL was able to demonstrate 3D printing of high strength aluminum alloys including Al 7075 and Al 6061 with crack-free microstructures and yield strength comparable to wrought material for the first time [1]. Recently HRL has been leveraging this technology to design high temperature aluminum alloys tailored for additive manufacturing. Related development efforts at HRL have enabled multi-material and graded alloy printing technologies.

Selected Publications:

1. J.H. Martin et al. “3D Printing of High Strength Aluminum Alloys” Nature 549, 365-369 (2017)
2. J.H. Martin et al “Grain refinement mechanisms in additively manufactured nano-functionalized aluminum” Acta Materialia 200 (2020)
3. M.R. O’Masta et al, “Island formation and the heterogeneous nucleation of aluminum” Computational Materials Science 192 (2021)
4. J.H. Martin et al. “Additive manufacturing of a high-performance aluminum alloy from cold mechanically derived non-spherical powder” Nature Communications Materials 4 (2023)

Ceramics are difficult to process and cannot be formed, cast or machined as easily as polymers or metals. Therefore, additive manufacturing technology could have a high impact, especially for intricate, complex-shaped or toughened ceramic parts. HRL has developed an additive manufacturing technology for ceramic matrix composites, whereby reinforcements are dispersed in a UV sensitive preceramic resin, which can be printed on standard light-based printers and subsequently converted to a ceramic [1,2,3]. HRL has recently extended this technology to micro-printing, fabricating vias with diameters and pitches as small as 9 µm and 18 µm, respectively [4]. This technology enables unprecedented via routing, including curved and angled vias, offering new packaging options for the 3D integration of microelectronic subsystems. One example shown above is an interposer intended to connect a curved infrared detector with a planar read-out integrated circuit (ROIC) that requires thousands of curved vias, that cannot be realized using conventional microelectronics processing approaches.

Selected Publications:

1. Z.C. Eckel, et al. “Additive Manufacturing of Polymer-derived Ceramics” Science 351 (2016)
2. J.M Hundley, et al. “Geometric Characterization of Additively Manufactured Polymer Derived Ceramics” Additive Manufacturing 18, 95-102 (2017)
3. M.R. O’Masta, et al. “Additive manufacturing of polymer-derived ceramic matrix Composites.” Journal of the American Ceramic Society 103, 6712-23 (2020)
4. T.A. Schaedler, et al. “Additive Manufacturing of Interposers with Curved Vias for Microelectronics Packaging” Additive Manufacturing 98, 104642 (2025)
5. M.R. O’Masta, et al. “Reinforcement Induced Microcracking during the Conversion of Polymer-Derived Ceramics.” Acta Materialia 275 120053 (2024).

This material is based upon work supported by the DARPA under Contract No. N66001-20-C-4012. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the DARPA.

Table: Efficacy data showing antimicrobial active levels (pH, ppm quaternary ammonium) and viral reduction before and after 5 years of simulated cleaning

The recent COVID-19 pandemic and the prospect of future global pandemics highlight the longstanding need to passively eliminate viruses and bacteria on surfaces. Conventional antimicrobial surfaces and coatings are typically constrained by a tradeoff between antimicrobial efficacy and physical durability. A biphasic polyurethane coating has been developed that breaks this tradeoff by incorporating a durability-imparting polycarbonate (PC) discrete phase with a continuous polyethylene glycol (PEG) transport phase that absorbs, stores, and releases antimicrobial active compounds for extended microbial inactivation. The biphasic polymer was shown to absorb carboxylic acid and quaternary ammonium antimicrobial active compounds, maintained their levels after five years of simulated cleaning, and inactivated up to 99.99% of Human Coronavirus 229E and Influenza A H1N1. Furthermore, the levels of antimicrobial active compounds on the biphasic coating could be augmented by cleaning with a disinfectant. The practicality of biphasic coatings for automotive and commercial aerospace environments was demonstrated by showing control of hardness and stain resistance through biphasic composition, showing environmental durability through heat, humidity, and light exposure, and passing flammability protocols.

This coating is part of a larger polymer structuring competency at HRL. We can model, synthesize, and test biphasic polymers made from two chemistries and obtain the best properties from each material. Obtaining simultaneous properties from two materials exceeds the performance of a copolymer that averages both properties or a single-phase suboptimal material.

Press Release:

Selected Publications:

Dual Component Passive Icephobic Coatings with Micron-Scale Phase-Separated 3D Structures

A passive icephobic coating (τice < 20 kPa) is an enabling technology to many industries, including aerospace and energy and power generation, with recent efforts in materials research identifying strategies to achieve this low adhesion threshold. To better meet this need, we have combined low surface energy perfluoropolyether (PFPE) and hydrophilic poly-(ethylene glycol) (PEG) species in a segmented polyurethane thermoplastic elastomer. Coating microstructure presents a segregated 3D morphology at the micron-scale (1−100 μm) with discrete PFPE and continuous PEG phases self-similar through the thickness. Spray application produces a solid, mechanically tough film free of additive fluids or sacrificial elements, demonstrating exceptional ice adhesion reduction up to 1000x lower versus aluminum (τice < 1 kPa), as measured under environmentally realistic accretion and centrifugal test shedding conditions. Finally, the modular nature of the synthetic system allows PEG and PFPE to be exchanged for poly(tetramethylene oxide) to investigate performance drivers.

Exceptional ice adhesion reduction was found for specific compositions of PEG and PFPE ratio components with 75% PEG / 25% PFPE showing an ice adhesion reduction of >1000 (τice < 1 kPa) with respect to an aluminum surface in a system with no added fluids. Synthetic flexibility of the system was used in the exchange of PFPE for PTMO, which reduced ice adhesion compared to aluminum but maintained passive icephobic properties (τice=19 kPa). Alternatively, the exchange of PEG for PTMO resulted in a fluoro-rich coating with only modest ice adhesion reduction (τice=83 kPa), likely due to the dominant presence of the fluoro phase at the surface and significantly altered microstructure versus other samples. While the mechanism requires further investigation, these systems reflect performance seen in low ice adhesion systems driven by bound water effects and fracture-driven inhomogeneous surface morphology. The ice adhesion performance of the PEG / PFPE system provides promising compositional and morphological design guidelines moving forward in passive icephobic coating systems. Future investigations will look to improve coating robustness and explore coating durability over multiple shedding cycles.

Publications:

1. A. P.; Gross, A. F.; Sherman, E.; Rodriguez, A. R.; Ventuleth, M.; Nelson, A. M.; Guan, S.; Gervasoni, M.; Graetz, J., ACS Applied Materials & Interfaces 2021, 13 (35), 42005-42013.
2. A. P.; Gross, A. F.; Sherman, E.; Rodriguez, A. R.; Ventuleth, M.; Nelson, A. M.; Sorensen, A.; Mott, R.; Graetz, J., Polymer 2021, 212, 123279.

Photochromic materials are useful for glare reduction, optical switches, and laser dazzling protection. While many photochromics darken rapidly, their reversal to a clear state is kinetically limited or requires optical excitations. Slow detinting times limit their use in applications where rapid clearing to restore visibility is needed for safe operation or faster cycling rates. Photochromic Cu-doped ZnS nanoparticles were recently discovered where darkening occurs via the reversible oxidation of the dopant. However, the detinting time depends on the concentration of environmental water and temperature to mediate the capture of a photoexcited hole. Instead of the environment regulating detinting times, interceding in carrier transport throughout assembled nanoparticles enables tunable and fast detinting. The nanoparticles' high surface area and small diameters enable the placement of hole traps near the surface to relax the excited darkened state and return to the clear ground state. Control of the amount of conjugation in the ligand and proximity to the surface reduces the detinting time by up to 8 fold. Finally, the nanoparticles were assembled into optical quality films to show industrial relevance.

The photochromic mechanism of photooxidation of a midgap dopant in a semiconductor was shown to be more broadly applicable than Cu doped ZnS. Cu doped ZnS is analyzed with density functional theory (DFT), a dopant-semiconductor band overlap is identified for the photochromic effect, and this feature is used to identify potential photochromics from DFT modeling of candidate compositions. Potential photochromic materials (dopant and semiconductor nanoparticle combinations) that function at longer wavelengths than UV triggered and visible darkening Cu doped ZnS are synthesized and their response was validated.

This photochromic research showcases the nanoparticle assembly and material modeling for discovery capabilities at HRL. Nanoparticle assembly has been demonstrated with optical and magnetic materials, and this work shows nanoparticle co-assembly with charged organics. For material modeling, we can model materials across length scales from DFT (nm) to FEA (cm), and have created discovery pipelines to identify novel compositions and structures.

There is a growing need for large structures in space, including solar arrays, antennas, reflective optics, and instrument arrays. However, building such large, mechanical structures is extremely difficult and costly due to the constraints imposed by launch. HRL is developing novel approaches for in-space fabrication and assembly of lightweight and high-strength structural elements.

Under DARPA's Novel Orbital and Moon Manufacturing, Materials, and Mass-efficient Design (NOM4D) program, HRL demonstrated that the sun can be used to permanently form inflatable metallic sheets into puncture-resilient truss elements that can be modularly assembled into lightweight, load-bearing structures. 50 µm - 100 µm thin metal foils are painted with gas-releasing hydride or hydrate on one side and selectively emissive coatings on the other, before laser-welding to seal. These preforms are then flat-packed for launch and inflated in space by exposure to sun light, after which they are assembled into structures.

HRL showcased these advancements by forming truss bay panels in a thermal vacuum chamber simulating the space environment. This technology could enable the deployment of space systems that are much larger than what is currently feasible.

Press Release: https://www.hrl.com/news/2023/01/11/hrl-laboratories-selected-for-nom4d-project-to-develop-space-based-construction-technologies

This material is based upon work supported by the Defense Advanced Research Projects Agency (DARPA) under Contract No. HR001122C0016. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Defense Advanced Research Projects Agency (DARPA).

HRL is developing materials innovations to improve electric motors for automotive and aviation applications. In close collaboration with General Motors, HRL is working on breaking the cost-performance paradigm in electric motors to enable affordable, high performance electric vehicles.

Funded by the Department of Energy’s ARPA-E, HRL has advanced development of materials architecture for permanent magnets optimizing the usage of critical heavy rare earth elements (Dysprosium and Terbium) through manipulation of manufacturing process and microstructure including crystallographic texture.

HRL has also invented novel rotor designs for aviation applications with a focus on electric vertical take-off and landing (eVTOL) aircraft that require high power density, high efficiency, and lightweight motors to maximize battery capacity and vehicle range.

Press Release: https://www.hrl.com/news/featured/2023/01/11/hrl-slam-project-will-develop-improved-electric-motor-magnets

Mechanical and thermal stimuli affect the magnetic permeability of magnetoelastic and thermomagnetic materials such as Galfenol (FeGa) and Monel (NiCu). HRL has been developing approaches to utilize these materials properties for stress and temperature sensing, for example by detecting magnetic permeability changes with induction coils.

Under DARPA’s Structural Evaluation through Non-contact Sensor Embedding (SENSE) program HRL is trying to revolutionize structural health monitoring. By embedding magneto-responsive sensing elements during additive manufacturing of load-bearing or stressed components, HRL can measure stress and temperature at critical locations inside the part. These wireless, non-contact measurements can detect damage in real time and forecast potential failure events, thereby enabling a path toward need-based parts maintenance. With this technology, HRL aims to change the costly, labor-intensive process for ensuring the safe operation of fatigue-limited structures (e.g. airplane, helicopter, train, and power plant components) based on regularly scheduled maintenance teardowns.

Press Release:

Advanced Imaging

Wide field of view imaging traditionally requires a large lens assembly and suffers from non-uniform brightness and sensitivity across the sensor. In contrast, animal eyes, comprising a curved imaging surface, are compact and light, while able to view over substantial angles. For instance, a human eye measures a mere 6 cm3, and can see across a >150° FOV, with up to 4,000 cycles/rad resolvable spatial frequency. HRL has developed multiple methods to spherically curve sensors to enable compact and high performance imaging. As applied to existing sensors, the methodology has been demonstrated on visible through infrared wavelengths and small to large formats, with publications on 1/2.3” visible CMOS sensors [3] and cryogenically-cooled, infrared sensors [2]. On-going work is investigating feasibility to reach near hemispherical limits, building a first-of-its-kind camera midwave infrared camera [4], as well as alternative bio-inspired imaging modalities.

Publications:

1. M.R. O'Masta, et al. "Curving of Large-Format Infrared Sensors.” In Infrared Technology and Applications XLVIII, 12107:429-35. SPIE, 2022. 1. M.R. O’Masta, et al. “Curving of Large-Format Infrared Sensors.” In Infrared Technology and Applications XLVIII, 12107:429–35. SPIE, 2022.
2. A. Kyrtsos, et al. “Machine-Learning-Assisted First-Principles Calculations of Strained InAs_1-xSb_x Alloys for Curved Focal-Plane Arrays.” Physical Review Applied 15, no. 6 (2021): 064008.
3. B. Guenter, et al. “Highly Curved Image Sensors: A Practical Approach for Improved Optical Performance.” Optics Express 25, no. 12 (2017): 13010–23.3 B. Guenter, et al. “Highly Curved Image Sensors: A Practical Approach for Improved Optical Performance.” Optics Express 25, no. 12 (2017): 13010–23.
4. https://www.hrl.com/news/2024/03/11/hrl-advances-to-camera-build-phase-of-curved-sensor-technology

This material is based upon work supported by the DARPA under Contract No. N66001‐20‐C‐4011. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the DARPA.

Sandwich structures are unique enablers of lightweight design, as they offer an exceptional combination of low density and high bending rigidity. Lightweight sandwich structures are widespread in aerospace applications (e.g. winglets, flaps, rudders, rotor blades) but are also used in many other industries. State-of-the-art sandwich panels are created by attaching thin, stiff composite or aluminum alloy facesheets to thick, lightweight honeycomb or foam cores. HRL has developed advanced core materials based on hollow metallic truss structures that offer improved compressive and shear strengths versus honeycombs. Hollow truss structures are preferably fabricated by coating a polymer template of the truss structure, which is subsequently removed. This approach converts a 2D thin film or coating into a 3D cellular material, thereby redefining the applications of a range of thin film/coating materials.

Selected Publications:

• T.A. Schaedler et al. “Ultralight metallic microlattices” Science 334 (2011)
• E.C. Clough et al. “Mechanical performance of hollow tetrahedral truss cores “ Int. J. of Solids and Structures 91 (2016)
• T.A. Schaedler et al. “Nanocrystalline Aluminum Truss Cores for Lightweight Sandwich Structures“ JOM (2017)

HRL has developed a platform technology to rapidly and scalably manufacture architected lattice materials based on polymers, metals, and ceramics suitable for a variety of applications. Architected materials with periodic cellular structure exhibit unprecedented properties that cannot be achieved with conventional materials. A self-propagating polymer waveguide process invented at HRL is used to additively manufacture architected polymer lattice structures 100-1000x faster than conventional 3D printing approaches such as stereolithography. HRL’s process is inherently scalable to large areas in addition to offering high throughput. HRL has developed photo polymer formulations for a broad range of applications including:

1. High strength and stiffness formulations for low-density sandwich panel cores
2. Viscoelastic formulations for padding and impact protection
3. Bio compatible formulations for biomedical and cellular scaffoldings
4. Dissolvable formulations for sacrificial templates essential for hollow microlattices
5. Preceramic formulations for polymer derived ceramic lattices and honeycombs

Selected Publications:

• A.L. Corrion et al. “Architected Microlattice Materials by Self-Propagating Waveguide Processing” TechConnect Briefs 2017, Advanced Manufacturing Innovation, Chapter 10 p.359 (2017)
• A.J. Jacobsen et al. “Micro-scale Truss Structures formed from Self-Propagating Photopolymer Waveguides” Advanced Materials 19 (2007)
• J. A. Kolodziejska et al. “Enabling ultra-thin lightweight structures: Microsandwich structures with microlattice cores” APL Materials 3 (2015)

Selected Publications:

• C.S. Roper et al. “Scalable 3D Bicontinuous Fluid Networks: Polymer Heat Exchangers Toward Artificial Organs” Advanced Materials 27 (2015)
• K. J. Maloney et al. “Multifunctional heat exchangers derived from three-dimensional micro-lattice structures” International Journal of Heat and Mass Transfer 55 (2012)