Anthony Rollett
Professor Carnegie Mellon University
- Pittsburgh PA
Tony Rollett's research is focused on advancing additive manufacturing with AI, simulation & matls. sci.
Biography
Areas of Expertise
Media Appearances
NASA Aeronautics Selects Three University Teams for Research Help
NASA online
2023-04-04
The JHU-CMU partnership is led by the University’s Somnath Ghosh, Michael G. Callas chair professor in the Department of Civil and Systems Engineering and director of the Computational Mechanics Research Laboratory, and CMU’s Anthony Rollett, a professor in the Department of Materials Science and Engineering and co-director of the Next Manufacturing Center.
CMU To Lead NASA Space Technology Research Institute
Carnegie Mellon University online
2023-03-20
"The STRI affords us an opportunity for a major collaboration through which we can construct the models that our partners at NASA very much need." — Tony Rollett
A route for avoiding defects during additive manufacturing
CMU Engineering News online
2020-11-27
“The real practical value of this research is that we can be precise about controlling the machines to avoid this problem,” says Anthony Rollett, a professor of materials science and engineeringOpens in new window and a lead co-author of the paper.
Department of Energy Awards Rollett $2.4 Million To 3D-Print Heat Exchangers
Carnegie Mellon University online
2019-10-23
The project, led by Anthony Rollett, a Carnegie Mellon University professor of materials science and engineering, is one of 18 projects being supported by the Department of Energy for high-temperature materials and is part of the High Intensity Thermal Exchange through Materials and Manufacturing Processes program.
Carnegie Mellon University and Argonne National Laboratory Unlock Keyhole Phenomenon in Metal 3D Printing
3D Printing Industry online
2019-02-25
Anthony Rollett, a co-author of the paper and Professor of Materials Science and Engineering at Carnegie Mellon University, said, “The research in this paper will translate into better quality control and better control of working with the machines.”
Media
Social
Industry Expertise
Accomplishments
Cyril Stanley Smith Award from TMS
2014
Fellow of TMS
2011
Member of Honor of the French Metallurgical Society
2015
Brahm Prakash Professor at the Indian Institute of Science (Bangalore)
2011
Chercheur d'Excellence (Outstanding Researcher). University of Lorraine
2012
Education
Cambridge University
M.A.
Metallurgy & Materials Science
1976
Drexel University
Ph.D.
Materials Engineering
1987
Links
Articles
Cost of Using Laser Powder Bed Fusion to Fabricate a Molten Salt-to-Supercritial Carbon Dioxide Heat Exchanger for Concentrating Solar Power
3D Printing and Additive Manufacturing2023
Advances in manufacturing technologies and materials are crucial to the commercial deployment of energy technologies. We present the case of concentrating solar power (CSP) with molten salt (MS) thermal storage, where low-cost, high-efficiency heat exchangers (HXs) are needed to achieve cost competitiveness. The materials required to tolerate the extreme operating conditions in CSP systems make it difficult or infeasible to produce them using conventional manufacturing processes. Although it is technically possible to produce HXs with adequate performance using additive manufacturing, specifically laser powder bed fusion (LPBF), here we assess whether doing so is cost-effective. We describe a process-based cost model (PBCM) to estimate the cost of fabricating a MS-to-supercritical carbon dioxide HX using LPBF.
Understanding process-microstructure-property relationships in laser powder bed fusion of non-spherical Ti-6Al-4V powder
Materials Characterization2023
Powder feedstock is a major cost driver in metal additive manufacturing (AM). Replacing the spherical powder with the cost-efficient non-spherical one can reduce the feedstock cost up to 50% and attract more interest to adopt AM in production and new alloy development. Here, a comprehensive study was conducted to understand process-microstructure-property relationships in laser powder bed fusion of hydride-dehydride Ti-6Al-4V powder. We demonstrated that variation of laser scan speed had a significant impact on the grain structure, pore evolution and properties compared to laser power. Dynamic X-ray radiography showed that with decreasing scan speed at a constant laser power, a transition from conduction to keyhole mode laser processing occurred, in which a deeper melt pool at lower scan speed intensified texture.
Variant selection in laser powder bed fusion of non-spherical Ti-6Al-4V powder
Journal of Materials Science & Technology2023
The presence of α/α′ on prior β/β grain boundaries directly impacts the final mechanical properties of the titanium alloys. The β/β grain boundary variant selection of titanium alloys has been assumed to be unlikely owing to the high cooling rates in laser powder bed fusion (L-PBF). However, we hypothesize that powder characteristics such as morphology (non-spherical) and particle size (50–120 µm) could affect the initial variant selection in L-PBF processed Ti-6Al-4V alloy by locally altering the cooling rates. Despite the high cooling rate found in L-PBF, results showed the presence of β/β grain boundary α′ lath growth inside two adjacent prior β grains.
Small dataset for hot cracking susceptibility of Al alloys and Ni alloys using dynamic X-ray radiography (DXR) technique
Data in Brief2023
Hot cracking as the major concern in the manufacturing process of metal alloys is detrimental to part performance and can lead to catastrophic failure. However, current research in this field is restricted to the scarcity of the relevant hot cracking susceptibility data. Here, using the DXR technique provided at 32-ID-B beamline of Advanced Photon Source (APS) at Argonne National Laboratory, we characterized the hot cracking formation in Laser Powder Bed Fusion (L-PBF) process for ten commercial alloys (Al7075, Al6061, Al2024, Al5052, Haynes 230, Haynes 160, Haynes X, Haynes 120, Haynes 214, and Haynes 718). The extracted DXR images captured the post-solidification hot cracking distribution and allow the quantification of the hot cracking susceptibility of those alloys.
Mapping nanocrystal orientations via scanning Laue diffraction microscopy for multi-peak Bragg coherent diffraction imaging
Journal of Synchrotron Radiation2023
The recent commissioning of a movable monochromator at the 34-ID-C endstation of the Advanced Photon Source has vastly simplified the collection of Bragg coherent diffraction imaging (BCDI) data from multiple Bragg peaks of sub-micrometre scale samples. Laue patterns arising from the scattering of a polychromatic beam by arbitrarily oriented nanocrystals permit their crystal orientations to be computed, which are then used for locating and collecting several non-co-linear Bragg reflections. The volumetric six-component strain tensor is then constructed by combining the projected displacement fields that are imaged using each of the measured reflections via iterative phase retrieval algorithms. Complications arise when the sample is heterogeneous in composition and/or when multiple grains of a given lattice structure are simultaneously illuminated by the polychromatic beam
Keyhole threshold and morphology in laser melting revealed by ultrahigh-speed x-ray imaging
Science2019
We used ultrahigh-speed synchrotron x-ray imaging to quantify the phenomenon of vapor depressions (also known as keyholes) during laser melting of metals as practiced in additive manufacturing. Although expected from welding and inferred from postmortem cross sections of fusion zones, the direct visualization of the keyhole morphology and dynamics with high-energy x-rays shows that (i) keyholes are present across the range of power and scanning velocity used in laser powder bed fusion; (ii) there is a well-defined threshold from conduction mode to keyhole based on laser power density; and (iii) the transition follows the sequence of vaporization, depression of the liquid surface, instability, and then deep keyhole formation. These and other aspects provide a physical basis for three-dimensional printing in laser powder bed machines.
