Research

The Structural Metallic Materials Group at Northwestern University, supervised by Prof. David C. Dunand, focuses on the mechanical behavior of metallic alloys, composites and foams. Concurrent research also addresses advanced processing techniques (e.g., to fabricate novel composites and foams) and microstructure characterization (e.g., to link the observed microstructure to the measured mechanical properties).

High Temperature Superalloys


*completed project/researcher graduated

Aluminum-based superalloys

Dr. Jacques Perrin Toinin, Dr. Anthony De Luca, Dr. Dinc Erdeniz, Richard Michi, and *Dr. Nhon Q Vo; in collaboration with Prof. David Seidman

We investigate microstructure and creep properties of binary and ternary Al-Sc-X, Al-Ti-X and Al-Zr-X alloys with nanoscale, coherent, coarsening-resistant precipitates. Additions of submicron alumina dispersoids are also investigated.

Cobalt-based superalloys

Dr. Jacques Perrin Toinin, Tony Chung, Fernando Reyes, Francesca Long, *Dr. James Coakley, *Dr. Peter Bocchini, and *Dr. Daniel Sauza; in collaboration with Prof. David Seidman

We are developing new high temperature alloys based on Cobalt. Methods such as creep and hardness tests are used to investigate the mechanical properties of these alloys and Atom Probe Tomography is utilized to study the structure.

Micro-architectured Ni-based superalloys

Dr. Dinc Erdeniz, *Dr. Cong Wang, and *Dr. Ashley PazyPuente

We are developing Ni-based superalloys with topologically-optimized micro-architectural features. We use the pack cementation technique to add Al,Ti and Mo to woven or braided structures fabricated from Ni or Ni-Cr wires and transform them into creep- and oxidation-resistant superalloys.

*Iron-based superalloys

*Dr. Sung Il Baik, *Dr. Mike Rawlings and *Dr. Nhon Q Vo

We are investigating the relationship between the processing and the creep resistance of ferritic superalloys that are strengthened by a hierarchical microstructure. This link is observed both experimentally and computationally.

Creep-Resistant Alloys


*completed project/researcher graduated

Creep of Thermoelectric Materials

Muath Mohammed Al Malki, co-advised by Prof. Jeffrey Snyder

We are exploring the relationship between creep deformation (during operation at stress and temperature) and thermoelectric performance degradation for various thermoelectric alloys.

Al-Ce Creep Resistant Alloys

Richard Michi and Yang Liu

Our work involves microstructural investigations and compression creep testing of Al-Ce binary alloys, with the goal of studying how Ce additions may be utilized to develop alloys with enhanced creep resistance.

Additive Manufacturing of Alloys


*completed project/researcher graduated

Densification mechanisms of 3D-printed micro-trusses

Dr. Christoph Kenel, in collaboration with Prof. Ramille Shah

Collaborating with the Shah lab, we aim to gain insight into the densification mechanisms upon reduction and sintering of 3D-printed structures. By learning about different sources of porosity and controlling them during sintering, we will ultimately tailor the structure for different applications.

Oxide Dispersion Strengthened Superalloys

Dr. Christoph Kenel and Jennie Glerum; co-advised by Dr. Jonathan Almer

We are investigating aluminum ODS alloys: first alumina dispersoids in a pure aluminum matrix, and then alumina and yttria dispersoids in an Al-Sc matrix capable of Al3Sc precipitation in solid state.

*Additive manufacturing of NiMnGa and NiTi shape memory microlattices

*Dr. Shannon Taylor, co-advised by Prof. Ramille Shah

In collaboration with the Shah lab, we are investigating the effects of the 3D-printing parameters and heat-treatment duration and temperature on the microstructure, porosity, and shape memory properties of the Ni-Mn-Ga and NiTi-Nb wires and micro-lattices.

*Additive manufacturing of tungsten by reduction and sintering

Jens Sesseg* and Micha Calvo*, co-advised by Prof. Spolenak (ETH Zurich)

Collaborating with the Prof. Spolenak's lab at ETH Zurich, we are fabricating tungsten micro-lattices, with 0/90º strut structures or more complex gyroid architectures. Partially-sintered struts with submicron open porosity are also infiltrated with Cu, resulting in a co-continuous W/Cu composites with wide W struts/Cu channel at the lattice scale, and fine W/Cu interpenetrating skeletons at the strut scale.

Freeze-Casting of Metals and Ceramics


*completed project/researcher graduated

Freeze-Casting of Iron Foams for Iron-Air Batteries

Stephen Wilke

We are investigating processing methods to achieve iron foams with hierarchical pore shape and size for hydrogen storage/generation purposes.

*Freeze-Casting of Silicon

Fernando Reyes

We are working to develop and establish the freeze-casting process for silicon foams for battery applications.

*Freeze-Casting of Directionally Solidified Ni-, Cu-, Co-, and W- Foams

*Sandra Häberli, *André Röthlisberger, *Hyeji Park, *Myounggeun Choi, and *Hyungyung Jo

We are working to develop and establish the freeze-casting process for copper and nickel foams with potential applications in energy areas.

Metallic Foams


*completed project/researcher graduated

Bulk nanostructured metals from twinned silver nanowires

Sarah Schlossberg, co-advised by Prof. Jiaxing Huang

Collaborating with the Huang lab, we are building a bulk nanostructured material from silver nanowires. We use multiply-twinned nanowires, assembled into a green body, to discover new metallic materials with exceptional properties and microstructures.

Hollow Nickel-Based Alloy Micro-Tubes via Directed Kirkendall Pore Formation

Dr. Dinc Erdeniz, *Dr. Ashley PazyPuente, and Aaron Yost

Typically, Kirkendall pores are considered detrimental because they deteriorate the mechanical, thermal, and electrical properties of materials, but we focus on the use of the Kirkendall effect as a novel route for the fabrication of β-NiAl(Cr) and shape memory NiTi microtubes.

*Micro-architectured Ni-based superalloys

Dr. Dinc Erdeniz, *Dr. Cong Wang, and *Dr. Ashley Pazy Puente

We are developing Ni-based superalloys with topologically-optimized micro-architectural features. We use the pack cementation technique to add Al,Ti and Mo to woven or braided structures fabricated from Ni or Ni-Cr wires and transform them into creep- and oxidation-resistant superalloys.

*Nanoporous Gold Foams

*Karen Yu-Chen Chen

Nanoporous gold has a sponge-like structure with extremely high surface due to the nanometer scale porosity. We use cutting-edge x-ray nano-tomography and in situ imaging to characterize the structural evolution of nanoporous gold during dealloying and coarsening.

*Iron-based Foams

*Justin Scott

We are investigating processing methods to achieve open-cell, ferritic steel foams for solid-oxide fuel cell interconnects. Mechanical properties at room temperature and typical use temperatures are being examined.

*Bulk Metallic Glass Foams

*Marie Cox

We are developing new a powder-based process to fabricate bulk metallic glasses (Zr57Nb5Al10Cu15 Ni13) with open, elongated pores. The structure and properties of these high-strength foams are studied.

*NiTi-based Foams

*Dr. Catherine Tupper, *Antoine Emery, and *Anselm Neurohr

We are investigating processing methods to achieve open or close-cell NiTi foams with superelastic or shape-memory compositions. We are also characterizing the mechanical properties of these foams.

*NiMnGa Foams

*Dr. Peiqi Zheng and *Antoine Emery, and *Dr. Ashley Pazy Puente

We are processing ferromagnetic shape memory Ni-Mn-Ga foams by replication casting and replication powder metallurgy methods. We are also characterizing their microstructure, composition, phase transformation temperatures and magnetic properties with our collaborators at Boise State University.

*Titanium Foams

*J. Li and *Y. Chino, and *S.M. Oppenheimer

We are investigating processing methods to fabricate titanium foams, including: freeze-casting, superplastic expansion of entrapped gas, and hot pressing.

Imaging and Strain Measurements via Synchrotron X-ray Diffraction


*completed project/researcher graduated

*Modeling of Bone Load Transfer Nanomechanics

*Dr. Fang Yuan

We are creating finite element models of bone structure at collagen fibril level to simulate their mechanical responses and compare with experimental data from synchrotron X-ray diffraction measurement. The detailed strain evolution in different phases of bone and the load transfer between them are studied.

*Load Transfer in Cortical Bone

*Dr. Anjali Singhal and *Dr. Fang Yuan

We are developing new high temperature alloys based on Cobalt. Methods such as creep and hardness tests are used to investigate the mechanical properties of these alloys and Atom Probe Tomography is utilized to study the structure.

*Load Transfer in Dentin

*Dr. Alix Deymier-Black and *Dr. Fang Yuan

High energy X-ray diffraction is being used to investigate load transfer behaviors between the ceramic and proteinaceous phases of dentin.

*Phase Change and Strain Evolution in Li-ion Batteries

*Matt Glazer

We are examining transient phase change and strain development phenomena during the use of Li-ion batteries and the effects of structure and hierarchical architecture on these phenomena using the Advanced Photon Source at Argonne National Laboratory.

Cultural Heritage Materials


*completed project/researcher graduated

*Artistic Bronzes

*Dr. Mike Rawlings and *Dr. Marcus Young

We are analyzing the composition and patinas of modern bronzes by artists such as Matisse, Brancusi and Picasso, and investigating the casting technology of bronzes from the early Western Zhou Dynasty.

*Cahokia Copper

*Dr. Alix Deymier-Black and *Matt Chastain

Copper Sheet artifacts from the Cahokia Mounds, IL are examined using metallurgical techniques to determine the forming techniques used by the Mississippians.