About

Jonathan Malen is a Raymond J. Lane Distinguished Professor in Mechanical Engineering at Carnegie Mellon University. His research focuses on advanced manufacturing and engineering design, contributing significantly to the development of innovative manufacturing processes and systems. As a leader in his field, he has been involved in advancing the understanding and application of manufacturing technologies, emphasizing the integration of design and manufacturing to improve efficiency and product quality.

Research topics

• Chemistry
• Materials science
• Condensed matter physics
• Composite material
• Chemical physics
• Physics
• Physical chemistry
• Crystallography
• Thermodynamics
• Optics
• Nanotechnology
• Electrical engineering
• Optoelectronics

Selected publications

• Direct evidence of mixed-phase induced anomalous thermal transport in hybrid perovskite single crystals

  Materials Today Physics · 2026-04-21

  article
  PublisherDOI

• Two-Color Thermography of GMAW to Enable Real-Time Hardness Prediction

  Welding Journal · 2025-08-01 · 2 citations

  articleOpen access

  Advanced process monitoring and model validation are essential for improving weld quality in both welding and welding-based additive manufacturing processes. Specifically, temperature is a key quantity of interest for understanding defect formation and microstructural evolution, which significantly impact mechanical properties. However, achieving accurate in-situ temperature imaging is challenging due to emissivity variations across the dynamic melt pool. To address this, we implemented a two-color imaging technique using a single commercial color camera to reduce temperature readings’ sensitivity to emissivity variations. High dynamic range images during melting were captured at various exposure times, and spatial and temporal filters were applied to minimize interference from the plasma arc emissions. The resulting temperature fields within the melt pool were then utilized to estimate cooling rates, which were further correlated to ex-situ hardness measurements. The strong correlation observed between cooling rates ranging from 20 to 600 K/s and hardness ranging between 250 to 400 HV demonstrated the potential of our easy-to-use two-color thermal imaging setup for preliminary evaluation of mechanical properties in a non-destructive manner. Beyond its significance for predicting mechanical properties, this technique provides a validated temperature measurement approach that can enhance the accuracy of physics-based models, such as those used to predict defect formation mechanisms, like porosity.

  PublisherDOI

• Phonon transport in Al-rich AlxGa1−xN thin films

  Journal of Applied Physics · 2025-08-22 · 1 citations

  articleOpen access

  AlxGa1−xN with a high Al composition (x) presents significant potential for advancing next-generation high-power electronic devices. To support the thermal design of AlxGa1−xN-based electronics, the thermal conductivity of AlxGa1−xN thin films was measured as a function of Al composition, temperature, and film thickness using time-domain thermoreflectance and frequency-domain thermoreflectance techniques. The measurement results were interpreted by modeling phonon transport in AlxGa1−xN films using the phonon Boltzmann transport equation. Phonon properties, including frequencies, group velocities, and lifetimes, were calculated using a virtual crystal approximation, with the effects of mass-disorder scattering incorporated via the Tamura model. The measured thermal conductivity of Al0.7Ga0.3N is an order of magnitude lower than those for GaN and AlN, exhibits an increase followed by saturation with temperature, and shows a modest decrease with a reduction in the film thickness. The modeling results agree with the measurement results and reveal that mass-disorder scattering and phonon-boundary scattering are the dominant mechanisms that reduce the thermal conductivity of AlxGa1−xN thin films.

  PublisherOA PDFDOI

• Inhomogeneities in directed energy deposition of refractory metals with widely different melting temperatures and mass densities

  Additive manufacturing · 2025-09-01

  articleOpen access
  PublisherDOI

• Anisotropic Thermal Conductivity in Imine-Linked Two-Dimensional Polymer Films Produced by Interfacial Polymerization

  ACS Nano · 2025-05-14 · 10 citations

  articleOpen accessSenior authorCorresponding

  Anisotropic thermal transport was measured in imine-linked two-dimensional polymer (2DP) films that were prepared by interfacial polymerization. Measurements of both in-plane (k∥) and cross-plane (k⊥) thermal conductivities relied on preparing free-standing 2DP films that were readily transferred for different measurement configurations. We polymerized two 2DP (Per-PDA and TAPPy-PDA) films at a liquid–liquid interface. These polycrystalline, imine-linked 2DP films are 100–200 nm in thickness and were measured by frequency domain thermoreflectance to extract k⊥ and a suspended calorimetric platform technique to evaluate k∥. We find that k∥ is larger than k⊥ in both materials at room temperature, leading to anisotropy ratios (k∥/k⊥) as high as 2.3. We attribute this behavior to the fact that the stiff, in-plane covalent bonds of 2DPs transport heat more effectively than the flexible, supramolecular cross-plane interactions. Variable–temperature measurements revealed a positive correlation between temperature and thermal conductivity, which we attribute to phonon scattering from grain boundaries and defects in the polycrystalline 2DP films. Molecular dynamics simulations of pristine crystals predict larger thermal conductivities and anisotropy ratios exceeding 7. The simulations suggest that as higher quality 2DP films become available, higher thermal conductivities and anisotropy ratios will also manifest.

  PublisherDOI

• High-speed imaging investigation and process mapping of the plume behavior in laser powder bed fusion

  Additive manufacturing · 2025-05-01 · 2 citations

  articleSenior authorCorresponding
  PublisherDOI

• Thermal conductivities of WC-Ni cermet powders for powder bed additive manufacturing

  Powder Technology · 2025-04-14 · 4 citations

  articleOpen accessSenior authorCorresponding

  The thermal conductivities of WC-Ni 10 and WC-Ni 17 cermet powders used in powder bed additive manufacturing processes were measured using the transient hot wire method. The 10 % and 17 % Ni by weight powders have measured thermal conductivities of 0.13 ± 0.02 Wm −1 K −1 and 0.15 ± 0.02 Wm −1 K −1 respectively at a temperature of 295 K and a pressure of 101 kPa – more than 25 % lower than common metal powders used in additive manufacturing. The WC-Ni powder grains are irregularly shaped and have a low average circularity, which causes a lower packing fraction and different contact geometry compared to a spherical powder bed. This results in reduced heat transfer through the gas assisted solid pathway of the powder bed and a lower overall powder thermal conductivity. The pressure dependence on the powder bed thermal conductivity was measured from 1 kPa to 101 kPa with both N 2 and He used as infiltrating gases. The powder bed thermal conductivity increased as the ambient pressure increased, and the magnitude of this pressure dependence was found to be a function of the infiltrating gas, not the powder composition. At 101 kPa infiltrating N 2 pressure, the WC-Ni 10 (WC-Ni 17 ) powder bed thermal conductivities increased from 0.13 (0.15) Wm −1 K −1 at 295 K to 0.17 (0.19) Wm −1 K −1 at 435 K. With this knowledge, thermal management of WC-Ni powder bed additive manufacturing techniques can be more accurately addressed. • Thermal conductivities of WC-Ni powders are measured with the transient hot wire method. • Pressure and temperature dependence of powder thermal conductivity are studied. • Gas pressure and composition significantly impact WC-Ni powder thermal conductivity. • WC-Ni powders exhibit high void fractions, low circularity, and irregular morphologies. • WC-Ni powders have lower thermal conductivities than commonly used metal powders.

  PublisherDOI

• Size effects and temperature dependence in the thermal conductivity of γ-Ga2O3 films

  Applied Physics Letters · 2025-06-09 · 2 citations

  articleSenior author

  The thermal conductivities of (100) γ-Ga2O3 films deposited on (100) MgAl2O4 substrates with various thicknesses were measured using frequency-domain thermoreflectance. The measured thermal conductivities of γ-Ga2O3 films are lower than the thermal conductivities of (2¯ 01) β-Ga2O3 films of comparable thickness, which suggests that γ-phase inclusions in the doped or alloyed β-phase may affect its thermal conductivity. The thermal conductivity of γ-Ga2O3 increases from 2.3−0.5+0.9 to 3.5±0.7 W/m K for films with thicknesses of 75–404 nm, which demonstrates a prominent size effect on thermal conductivity. The thermal conductivity of γ-Ga2O3 also shows a slight increase as temperature increases from 293 to 400 K. This increase in thermal conductivity occurs when defect and boundary scattering suppress signatures of temperature-dependent Umklapp scattering. γ-Ga2O3 has a cation-defective spinel structure with at least two gallium vacancies in every unit cell, which are the likely source of defect scattering.

  PublisherDOI

• Tacticity-dependent thermal conductivity of single polymer chains

  Applied Physics Letters · 2025-06-30 · 2 citations

  article

  While the effect of polymer chain tacticity on crystallinity, glass transition dynamics, and viscoelastic coefficients has been studied, its impact on thermal transport is unknown. Here, molecular dynamics simulations are used to determine the tacticity-dependent thermal conductivity of extended single chains of polypropylene and polystyrene. Chains with ordered tacticity show a threefold enhancement in thermal conductivity compared to chains with random tacticity. A kinetic theory-based model indicates that the enhancement results from a combination of large mean free paths and velocities of energy carriers. This work introduces tacticity control as a strategy to develop thermally conductive polymers.

  PublisherDOI

• Gold Sapphire Interface 4-Parameter Modeled Data w/ Uncertainty

  KiltHub Repository · 2025-01-01

  datasetOpen access

  Simulated FDTR phase lag data for a gold on sapphire sample, for a range of possible values of 4 input parameters (laser spot size, substrate thermal conductivity, gold layer thickness, and interface thermal conductance). This dataset contains the primary simulation data of a research project, however it will not contain every post-processing file associated with the research. That will instead be stored on an associated GitHub repo, which will be linked here after it has been fully created. The data in this submission is analyzed and discussed in an associated research manuscript which is in preparation for submission.<br>

  PublisherDOI

Recent grants

• GOALI:Tradeoffs in Heat Dissipation and Optical Performance at Plasmonic Interfaces

  NSF · $340k · 2014–2017

• GOALI: Local thermoreflectance measurement of evaporative heat transfer in the thin film region of a dynamic meniscus

  NSF · $333k · 2018–2022

• CAREER:Thermal Energy Transport in Organic-Inorganic Hybrid Materials

  NSF · $400k · 2012–2017

• Collaborative Research: Electric Field- and Light-Modulated Thermal Transport in Superatomic Crystals

  NSF · $290k · 2020–2024

• GOALI: Thermal Transport by Phonons in Device-Grade Nitride Nanostructures

  NSF · $397k · 2011–2014

Frequent coauthors

• Alan J. H. McGaughey

  Carnegie Mellon University

  63 shared

• Wee‐Liat Ong

  59 shared

• Xavier Roy

  Columbia University

  34 shared

• Daniel W. Paley⧓

  Lawrence Berkeley National Laboratory

  31 shared

• C. Fred Higgs

  Rice University

  28 shared

• Patrick Dougherty

  26 shared

• Arun Majumdar

  Stanford University

  25 shared

• Evan O'Brien

  25 shared

Education

• Ph.D., Mechanical Engineering

  University of California, Berkeley

  2009

• M.S., Nuclear Engineering

  Massachusetts Institute of Technology

  2003

• B.S., Mechanical Engineering

  University of Michigan, Ann Arbor

  2000

Awards & honors

• Benjamin Richard Teare Teaching Award (2019)
• David P. Casasent Outstanding Research Award (2016)
• ASME Bergles-Rohsenhow Young Investigator Award in Heat Tran…
• Army Research Office Young Investigator Award (2014)
• National Science Foundation CAREER Award (2012)