About

Ashwin Shahani is an Associate Professor in the Michigan Materials Science and Engineering department. He holds a Ph.D. in Materials Science and Engineering from Northwestern University, obtained in 2016, and a B.S. in Materials Science and Engineering from Cornell University, earned in 2012. His research interests focus on the intersection of solidification science and advanced materials characterization. Professor Shahani and his team work toward understanding the fundamental processes underlying the structural transformations of crystals, including classical and quasicrystalline structures, during solidification and grain growth. His group employs a variety of synchrotron- and laboratory-based methods, such as X-ray tomography and diffraction, to observe crystal growth dynamics in real-time. These studies leverage advancements in data sampling, reconstruction algorithms, computer hardware, and large dataset processing in a massively parallel environment. The goal is to develop a new paradigm in solidification and processing science through in situ and multimodal approaches. Professor Shahani has received multiple awards, including the NSF CAREER Award in 2019, the ASM Bradley Stoughton Award for Young Teachers in 2022, and the TMS Frontiers of Materials Award in 2023, among others.

Research topics

• Artificial Intelligence
• Computer Science
• Optics
• Engineering
• Mechanical engineering
• Materials science
• Physics

Selected publications

• Beyond the eutectic paradigm: nanolamellar patterns in a rapidly solidified peritectic alloy

  Materials Research Letters · 2026-04-01

  articleOpen accessSenior authorCorresponding

  Peritectic transformations are central to many structural alloys, yet pattern formation remains poorly understood due to complex growth dynamics and limited three-dimensional data. Here, we report an unusual two-phase microstructure in a Zn–Ag peritectic alloy subjected to rapid solidification by laser surface remelting. Synchrotron X-ray nanotomography reveals a lamellar structure of primary [Formula: see text]AgZn[Formula: see text] and peritectic Zn with ∼700 nm spacing. Although resembling a eutectic morphology, this pattern forms without a eutectic reaction through non-steady coupled growth from the liquid. SEM and TEM-EDS confirm interface shapes and phase compositions. These findings expand the design space of peritectics for refined microstructural control.

  PublisherDOI

• Crystal orientation effects on irregular vs. regular growth patterns in faceted/nonfaceted eutectics

  European Synchrotron Radiation Facility · 2026-01-22

  datasetOpen accessSenior author

  The composite growth dynamics, in particular the transformation from irregular to regular patterns, in eutectic alloys that solidify by involving a faceted (f) and a nonfaceted (nf) solids is poorly understood. It is suspected, but not demonstrated, that the process depends on changes in the interfacial kinetics of facets when control parameters (growth rate, composition, …) are varied, and on crystal orientation. Indeed, the interplay between diffusion controlled growth and crystallographic mechanisms (e.g. micro-twinning) remains obscure. For significant progress, f/nf eutectic microstructures of known solidification history must be inspected in terms of morphology and crystallography. We will explore thin (10 µm) Al-Al3Ni and Al-Si films with typical microstructures generated beforehand by in situ directional solidification. Crystallographic mapping of representative areas will be done by non-destructive Laue micro-diffraction measurements through a sapphire substrate.

  PublisherDOI

• In-situ DFXM Study of Grain Boundary Migration in CuAlMn

  Open MIND · 2026-03-01

  dataset1st authorCorresponding

  Grain boundary migration in real alloys is often governed by stored strain energy rather than curvature, yet direct experimental observations remain scarce. We propose a three-day in-situ dark field X-ray microscopy (DFXM) experiment at ID03 to investigate strain-energy-driven grain boundary migration and dislocation generation in the Cu71.6Al17Mn11.4 shape memory alloy. By focusing on isolated flat grain boundaries and single-grain reference samples, we eliminate curvature and network effects and directly probe the role of plastic strain.

  DOI

• Beyond the eutectic paradigm: nanolamellar patterns in a rapidly solidified peritectic alloy

  Figshare · 2026-04-02

  articleOpen accessSenior author

  Peritectic transformations are central to many structural alloys, yet pattern formation remains poorly understood due to complex growth dynamics and limited three-dimensional data. Here, we report an unusual two-phase microstructure in a Zn–Ag peritectic alloy subjected to rapid solidification by laser surface remelting. Synchrotron X-ray nanotomography reveals a lamellar structure of primary ε-AgZn3 and peritectic Zn with ∼700 nm spacing. Although resembling a eutectic morphology, this pattern forms without a eutectic reaction through non-steady coupled growth from the liquid. SEM and TEM-EDS confirm interface shapes and phase compositions. These findings expand the design space of peritectics for refined microstructural control.

  PublisherDOI

• Beyond the eutectic paradigm: nanolamellar patterns in a rapidly solidified peritectic alloy

  Figshare · 2026-04-02

  articleOpen accessSenior author

  Peritectic transformations are central to many structural alloys, yet pattern formation remains poorly understood due to complex growth dynamics and limited three-dimensional data. Here, we report an unusual two-phase microstructure in a Zn–Ag peritectic alloy subjected to rapid solidification by laser surface remelting. Synchrotron X-ray nanotomography reveals a lamellar structure of primary ε-AgZn3 and peritectic Zn with ∼700 nm spacing. Although resembling a eutectic morphology, this pattern forms without a eutectic reaction through non-steady coupled growth from the liquid. SEM and TEM-EDS confirm interface shapes and phase compositions. These findings expand the design space of peritectics for refined microstructural control.

  PublisherDOI

• A spectral criterion for faceting at alloy solid-liquid interfaces

  Scripta Materialia · 2026-02-20 · 2 citations

  articleOpen access1st authorCorresponding

  A long-standing question in solidification is which interfaces are atomically smooth and which are rough. The classical Jackson factor addresses this for pure substances via a single nondimensional ratio between latent heat and thermal energy. Here, I derive a generalization for an n -component alloy that remains algebraic yet captures coupling between species. Starting from a bond-counting free energy on a partially filled surface layer, I compute the Hessian at the “rough” coverage point and, after an exact concentration rescaling, obtain an n × n coupling matrix S . The interface is rough if the largest eigenvalue satisfies λ max ( S ) < 2; otherwise, it facets along the top eigenvector. This spectral criterion reduces to Jackson’s α < 2 for a single component, gives eigenvalue-free row-sum bounds, and provides closed forms for important symmetry classes (e.g., B2 {110}). Applications to Al-rich multicomponent alloys show how both microalloying and complex chemistries amplify λ max ( S ), rationalizing the observation that “complexity promotes faceting.”

  PublisherDOI

• Emergence of complex-regular eutectic patterns in Al–Ge: Observations from correlative nano-imaging

  Acta Materialia · 2026-03-16 · 1 citations

  articleOpen accessSenior authorCorresponding

  Eutectic solidification exemplifies nonequilibrium pattern formation, making it a well-studied moving boundary problem. Yet the mechanisms behind the formation of complex-regular microstructures — particularly in highly anisotropic systems with a significant volume fraction of a faceted phase — remain poorly understood. Our understanding of such systems is made complicated by the nonlinear interface kinetics and unique growth dynamics characteristic of faceted phases. To address these challenges, we investigate a model Al-Ge eutectic system, where the faceted Ge phase constitutes a substantial volume fraction ( ∼ 0.35) and where the two solid phases arrange into so-called “fishbone” or “feather” complex-regular patterns. Using synchrotron-based x-ray nano-imaging and nanotomography with high spatial resolution (22 nm per pixel), we capture in real-time the evolution of the solid–liquid interfaces and the resulting three-dimensional microstructures in this faceted/non-faceted eutectic system. By integrating these observations with electron backscattered diffraction, we elucidate the crystallographic biases on the solidification process and the mechanisms driving the formation of such complex-regular microstructures. These findings inform a new growth model for irregular eutectics in (near-)symmetrical phase diagrams, offering insight on advanced microstructural design and processing strategies. More broadly, we demonstrate how interfacial curvature is generated in irregular eutectic alloys and how it depends on the volume fraction of the faceted phase.

  PublisherDOI

• Imaging of dynamic processes in materials with a laser-wakefield accelerator

  Physical Review Applied · 2025-11-10

  articleOpen access

  Betatron x rays generated from laser-wakefield accelerators are a promising source for imaging dynamic processes in materials. Here, we present proof-of-concept imaging of microstructural evolution in a hypermonotectic <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>Al</a:mi> </a:math> - <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>Bi</c:mi> </c:math> alloy, which consists of liquid <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mi>Bi</e:mi> </e:math> particles in a solid <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mi>Al</g:mi> </g:math> matrix. The images capture the elongation and fragmentation of <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mi>Bi</i:mi> </i:math> particles upon isothermal annealing. Because of the femtosecond time scale of the betatron source, the images are not subject to motion blur, whereas the accessibility of the source allows for studies of long-term processes such as annealing. The high-resolution data reveal that the evolution of <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mi>Bi</k:mi> </k:math> particles is mediated by an interplay of grain-boundary wetting and morphological instability, in stark contrast to an earlier proposal for (inverse) coarsening.

  PublisherDOI

• Solidification Processing by Low-Power Electric Current: Towards Phase Control in Aluminum Alloys

  ˜The œminerals, metals & materials series · 2025-01-01

  book-chapter
  PublisherDOI

• Establishing topological benchmarks for three-dimensional x-ray diffraction microscopy

  Materials Research Letters · 2025-06-09 · 3 citations

  articleOpen access1st authorCorresponding

  A quantitative characterization of 3D topology is paramount for understanding microstructure and its time-evolution. This Perspective establishes a framework to evaluate the accuracy of emergent 3D x-ray diffraction microscopy (3DXRD) methods in capturing topological features, such as the grain boundaries, triple-junctions, and their correlations over topological distance. As a case study, we compare reconstructions from synchrotron- and laboratory-based x-ray diffraction tomography. We find the laboratory technique distorts connectivity of grains, and these discrepancies propagate over larger topological distances. By benchmarking these techniques against simulations and theory, we highlight the strengths and limitations of 3DXRD methods for 3D grain topology reconstruction.

  PublisherDOI

Recent grants

• CAREER: Microstructure Formation in Chemically-Modified Eutectics: Bridging Real-Time Imaging, Machine Learning, and Problem-Based Instruction

  NSF · $500k · 2019–2024

Frequent coauthors

• Peter W. Voorhees

  Levine Cancer Institute

  14 shared

• Xianghui Xiao

  Brookhaven National Laboratory

  13 shared

• Nancy Senabulya

  University of Michigan–Ann Arbor

  12 shared

• A. G. R. Thomas

  University of Michigan–Ann Arbor

  11 shared

• Insung Han

  University of Oxford

  11 shared

• Paul Chao

  Sandia National Laboratories

  11 shared

• Saman Moniri

  University of California, Los Angeles

  10 shared

• Ning Lu

  University of Michigan–Ann Arbor

  10 shared

Education

• Ph.D., Materials Science and Engineering

  Northwestern University

  2016

• B.S., Materials Science and Engineering

  Cornell University

  2012

Awards & honors

• AFOSR YIP Award (2017)
• ARO YIP Award (2018)
• NSF CAREER Award (2019)
• MSE Faculty Outstanding Accomplishment Award (2021)
• ARO ECASE Award (2022)