About

Christopher Rock is an Associate Research Professor at NC State University's Edward P. Fitts Department of Industrial and Systems Engineering. He joined CAMAL in November 2016 after a long and productive tenure at ATI, where he worked in nickel product development, new melting technologies, powder metallurgy, additive manufacturing, and process modeling. Prior to ATI, he was employed at PCC Special Metals in West Virginia as a melt engineer and R&D process engineer. His professional interests include developing new alloys for various markets using additive manufacturing, process modeling and development, and implementing new sensor technologies for process monitoring. His educational background includes a Ph.D., a Master of Science, and a Bachelor of Science in Materials Science and Engineering from the University of Kentucky, completed in 1997, 1993, and 1991 respectively.

Research topics

• Materials science
• Metallurgy
• Composite material
• Chemical engineering
• Chemistry

Selected publications

• A Methodology for Manufacturing 3D Disordered Metamaterials Using Laser Powder Bed Fusion from Granular Packings and Hyperuniform Point Clouds

  2026-03-09

  articleOpen accessSenior author

  Three-dimensional open geometries originating from nontraditional manufacturing designs such as point clouds, sphere packings, and mathematical file generation can be challenging to manufacture when the structures have disorder and overhanging geometric features. This study algorithmically created rigid 3D geometries representing granular packings and hyperuniform point clouds suitable for fabricating metallic disordered metamaterial (MDM) geometries using additive manufacturing. This approach produced nonrepeating connecting beam angles ranging from 0° to 90° relative to the build plate. Prototyping using laser powder bed fusion (LPBF) was challenging for the low-angle connecting beams, due to heat transfer differences when printing on powder compared with a solid substrate. An initial set of unsupported MDM geometries revealed failed connecting beams and geometric inaccuracy. We performed a systematic study to emulate the complex beam angles by printing cylinders ranging from 1.0 mm to 3.0 mm in diameter and angles ranging from 10°, to 90°, relative to the build plate. Unsupported connecting beams tended to lose geometric integrity at angles below 30°, and failed at 10°, resulting in geometric deviation on the downfacing surfaces. However, varying LPBF input energies and support strategies mitigated the geometric deviati

  PublisherDOI

• Comparing dragonfly wings to jars of marbles through the lens of hyperuniformity

  ArXiv.org · 2025-08-08

  preprintOpen accessSenior author

  When we look at the world around us, we see both organized (also called ordered) and disorganized (also called disordered) arrangements of things. Carefully-tiled floors and brick walls have organized and repeating patterns, but the stars in the sky and the trees in a forest look like they're arranged in a disordered way. We also see objects, like jars of marbles and the lacy wings of insects, that lie between ordered and disordered extremes. Although the marbles in a jar don't sit on a regular grid like carefully-arranged tiles, the collection of marbles does have some consistent features, such as the typical size and spacing between them. However, the positions of the marbles are much less random than the positions of the stars in the sky. To help understand and classify these patterns, mathematicians and physicists use the term hyperuniform to help them describe the situations of being perfectly organized or being disorganized in an organized way. In this article, we discuss various fascinating properties of hyperuniform patterns. We explore where they occur in the natural world and how engineers are using them to build new structures.

  PublisherOA PDFDOI

• Chemistry effects on ODS steel consolidated via laser powder bed fusion from GARS powder

  Materials Characterization · 2025-05-06 · 3 citations

  article
  PublisherDOI

• Solidification Pathway, Phase Stability, and High-Temperature Deformation Mechanisms of a Dual-Phase High-Entropy Alloy

  Preprints.org · 2025-03-18

  preprintOpen access

  High-entropy alloys (HEAs) offer a platform for designing microstructures suited to extreme conditions. Dual-phase HEAs show promising strength-ductility combinations at high temperatures, but maintaining phase stability above 800°C remains challenging. This study introduces a novel dual-phase HEA (FCC + BCC) with microstructural evolution driven by spinodal decomposition and intermetallic stabilization. The alloy transitions from initial FCC to mixed FCC-BCC laths, with spinodal nanophases in the BCC matrix. Coarse σ (FeCr-type) and NiZr-rich intermetallics form at phase boundaries, enhancing stability. Post-solidification analysis shows σ phase consuming spinodal BCC at high temperatures, while retained nanoscale BCC spinodal contributes to strain incompatibility and HDI hardening. This interplay balances phase stability and mechanical performance. Compressive tests at 800-1000°C (strain rate 1/s) reveal phase stability and deformation mechanisms. Behavior is governed by lamellar morphology and σ/α-Cr ↔ B2 interactions. Retained GNDs and enhanced twinning sustain work hardening up to 900°C. At 1000°C, FCC-dominated strain localization triggers rapid softening via dynamic recrystallization. These findings deepen understanding of high-temperature deformation in dual-phase HEAs, offering pathways for optimizing alloy design in extreme environments.

  PublisherOA PDFDOI

• Solidification Pathway, Phase Stability, and High-Temperature Deformation Mechanisms of a Dual-Phase High-Entropy Alloy

  High Entropy Alloys & Materials · 2025-10-09 · 2 citations

  articleOpen access

  Abstract High-entropy alloys (HEAs) offer a pathway for designing microstructures suited to extreme conditions. Eutectic HEA’s leverage a combination of phase ordering, interfacial strengthening, secondary phase strengthening, and heterodeformation induced (HDI) strengthening to achieve high strength and ductility at elevated temperatures. Maintaining these properties past 700 °C has proved challenging due to limitations in phase stability and breakdown of work hardening mechanisms. This paper set out to produce a dual-phase HEA with enhanced high-temperature stability and work hardenability by leveraging the enhanced HDI strengthening. We have designed a dual-phase hierarchical AlCoCrFeNi(CuTiZr) HEA comprised lamellar composite regions containing FCC(L1 2 ) lamella in a continuous BCC(B2) matrix which is surrounded by coarse FCC(L1 2 ) grains. A Cr-rich fine scale spinodal phase forms within the BCC regions, in addition to slow forming coarse FeCr-type σ phases in the lamellar FCC and minor NiZr intermetallic phase at the coarse FCC-BCC boundaries. Annealing of the cast samples at 1100 °C for 50 h and quenching breaks down the cast lamellar structure, disorders the FCC, and dissolves the coarse σ phases, while preserving the near equal ratio of FCC to BCC and the Cr-rich spinodal phase. Under compression at 800 °C (1/s strain rate), both the as-cast and high-temperature annealed structures display high strength and work hardening. With increasing temperature, a higher degree of strain partitioning is observed in the annealed structure than the as-cast, resulting in an increase in the peak flow and sustained work hardenability at 900 °C and early onset of strain softening in the annealed structure at 1000 °C due to localized activation of dynamic recrystallization. The persistence of this strain partitioning in the annealed samples corresponds to the enhanced thermal stability of the spinodal Cr phase strengthening the BCC(B2) regions. Above 800 °C, this spinodal phase is consumed in the as-cast structure to fuel the growth of coarser σ and α-Cr phases. The absence of these coarser phases in the annealed condition results in the growth of the spinodal phase and enhanced high-temperature strength of the BCC(B2) regions and enhanced heterodeformation at elevated temperatures. These findings deepen understanding of high-temperature deformation in dual-phase HEAs, offering pathways for optimizing alloy design in extreme environments.

  PublisherOA PDFDOI

• Electrical transport in tunably disordered metamaterials

  Physical review. E · 2025-09-25

  article

  Naturally occurring materials are often disordered, with the dependence of their bulk properties on structure being challenging to predict due to the lack of underlying crystalline axes. In this paper, we develop a digital pipeline from algorithmically created configurations with tunable disorder to 3D printed materials, as a tool to aid in the study of such materials, using electrical resistance as a test case. The designed material begins with a random point cloud that is iteratively evolved using Lloyd's algorithm to approach uniformity, with the points being connected via a Delaunay triangulation to form a disordered network metamaterial. Utilizing laser powder bed fusion additive manufacturing with stainless steel 17-4 PH and titanium alloy Ti-6Al-4V, we are able to experimentally measure the bulk electrical resistivity as a function of the degree of disorder in the network. The effective resistance of the structure calculated from the combinatorial weighted graph Laplacian is in good agreement with experimental data. However, the effective resistance is sensitive to anisotropy and global network topology, preventing a single network statistic or disorder characterization from predicting global resistivity.

  PublisherDOI

• Electron Beam Powder Bed Fusion of ATI C103TM Refractory Alloy

  Metallurgical and Materials Transactions A · 2024-05-26 · 21 citations

  articleOpen access

  Abstract The study investigated the use of electron beam powder bed fusion (EB-PBF) to fabricate niobium ATI C103™ alloy articles for microstructural characterization and mechanical testing. The feedstock powder was consolidated into low-porosity articles, and both powder and sample chemistry were monitored. Oxygen uptake in the powder was limited to less than the ASTM B655/B655M (2018) specification limits for 7 uses. Manipulating vacuum chamber pressure showed stable hafnium content but decreasing titanium content with decreasing chamber pressure attributed to evaporation. AM samples were evaluated in the post-processed, as-fabricated, annealed, and hot isostatic pressing (HIP) condition with a maximum yield strength of 287 MPa, UTS of 375 MPa for the HIP, and maximum elongation of 32 pct for the annealed specimens, respectively. Mechanical properties are similar to typical wrought products, with a notable increase in yield strength after post-processing by HIP. The fracture behavior was driven by porosity in the as-fabricated specimens and grain boundary fracture after HIP.

  PublisherOA PDFDOI

• Electrical Transport in Tunably-Disordered Metamaterials

  arXiv (Cornell University) · 2024-10-15

  preprintOpen access

  Naturally occurring materials are often disordered, with their bulk properties being challenging to predict from the structure, due to the lack of underlying crystalline axes. In this paper, we develop a digital pipeline from algorithmically-created configurations with tunable disorder to 3D printed materials, as a tool to aid in the study of such materials, using electrical resistance as a test case. The designed material begins with a random point cloud that is iteratively evolved using Lloyd's algorithm to approach uniformity, with the points being connected via a Delaunay triangulation to form a disordered network metamaterial. Utilizing laser powder bed fusion additive manufacturing with stainless steel 17-4 PH and titanium alloy Ti-6Al-4V, we are able to experimentally measure the bulk electrical resistivity of the disordered network. The effective resistance of the structure calculated from the combinatorial weighted graph Laplacian is in good agreement with experimental data. However, the effective resistance is sensitive to anisotropy and global network topology, preventing a single network statistic or disorder characterization from predicting global resistivity.

  PublisherOA PDFDOI

• Dual-Phase High Entropy Alloy for High-Temperature Application

  Preprints.org · 2024-07-24

  preprintOpen access

  High temperature Ni-superalloys are limited by reliance on critical elements and complex processing steps. High entropy alloys (HEAs) have demonstrated stable single/dual phase microstructures with strong ordering tendencies. A dual phase (FCC+BCC) Al0.5Co0.5CrFeNi1.5Ti0.25 alloy (developed using CALPHAD) was tested for room and high temperature compression behavior. The microstructure mainly comprises of coarse ordered FCC(L12) surrounding decomposed lamellae of ordered FCC(L12) and BCC(L21) phases, which coarsened upon annealing at high temperature (1100 °C) into a bi-continuous structure of disordered FCC+BCC(B2). Additionally, cold rollability of the cast alloy increased from <5% to ~40% after annealing, with a corresponding softening observed in room temperature compression mainly due to disordering of FCC and BCC phases. Peak flow stresses of 793.45MPa, 535.12MPa, and 324.40MPa were achieved at 800oC, 900oC, and 1000oC respectively for the high temperature annealed alloy.

  PublisherOA PDFDOI

• Microstructure development and properties of micro-alloyed copper, Cu-0.3Zr-0.15Ag, produced by electron beam additive manufacturing

  Materials Characterization · 2023-01-13 · 7 citations

  articleOpen access

  A micro-alloyed copper powder, Cu-0.3Zr-0.15Ag wt%, was produced using gas atomization reaction synthesis. Zirconium was added to copper to sequester the oxygen present as copper oxide surface films on the powder particles. The as-received powders, as well as the intentionally oxidized powders were used to fabricate solid test articles by electron beam powder bed fusion additive manufacturing. Dense samples fabricated from as-received powder demonstrated nominal UTS, yield, and elongation values at 260 MPa, 150 MPa, and 34%, respectively. The average electrical conductivity of these samples was measured at 95% of the international annealed copper standard (IACS). Samples fabricated from the oxidized powder exhibited nominal UTS, yield, and elongation of 241 MPa, 146 MPa, and 43%, respectively, with an electrical conductivity of 95% IACS. During characterization, it was observed that, rather than forming nano-scale dispersoids, the Zirconia (ZrO2) appeared as discontinuous stringers in the metallographic cross-sections that crossed grain and melt pool boundaries. This was rationalized by tracing the presence of the micro-alloying addition of elemental zirconium, which was found to react with surface oxides dissociated in the melt pool to form ZrO2, which then solidified on the surface of the melt pool through an allotropic transformation to monoclinic ZrO2 in discontinuous films and spheroids ranging in size from nanometers to microns. This was confirmed by microscopic analysis of the tops of the melt pools. On subsequent melt passes, these ZrO2 structures were displaced and redistributed within the melt pool.

  PublisherDOI

Frequent coauthors

• Tim Horn

  RadiaBeam Technologies (United States)

  17 shared

• Iver E. Anderson

  Iowa State University

  12 shared

• Emma White

  Government of the United States of America

  9 shared

• Tim Prost

  Ames National Laboratory

  8 shared

• Christopher Ledford

  Government of the United States of America

  8 shared

• R. E. Napolitano

  6 shared

• Kenji Okazaki

  Kobe University

  5 shared

• Sourabh Saptarshi

  5 shared