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Search Publications by: Brian Simonds (Fed)

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Displaying 1 - 25 of 33

NIST efforts in extreme-ultraviolet metrology

November 21, 2023
Author(s)
Charles S. Tarrio, Steven Grantham, Rob Vest, Thomas A. Germer, Bryan Barnes, Stephanie Moffitt, Brian Simonds, Matthew Spidell
For several decades, the National Institute of Standards and Technology (NIST) has actively supported metrology programs for extreme ultraviolet (EUV) lithography. We will describe our existing programs in optics lifetime, reflectometry, and radiometry

Modes of laser melting in additive manufacturing of metals

October 20, 2022
Author(s)
Cang Zhao, Bo Shi, Shuailei Chen, Tao Sun, Brian Simonds, Anthony Rollett
In the laser powder bed fusion additive manufacturing of metals, extreme thermal conditions create many highly dynamic physical phenomena, such as vaporization and recoil, Marangoni convection, and protrusion and keyhole instability. Collectively, however

In situ absorption synchrotron measurements, predictive modeling, microstructural analysis, and scanning probe measurements of laser melted Ti-6Al-4V single tracks for additive manufacturing applications

December 29, 2021
Author(s)
Nicholas Derimow, Edwin Schwalbach, Jake Benzing, Jason Killgore, Aly Artusio-Glimpse, Nik Hrabe, Brian Simonds
In this work, the fundamental processing-structure-property (PSP) relationships that govern laser-based additive manufacturing were investigated with the Ti-6Al-4V alloy. X-ray synchrotron imaging carried out in conjunction with in-situ integrating sphere

The causal relationship between melt pool geometry and energy absorption measured in real time during laser-based manufacturing

December 16, 2021
Author(s)
Brian Simonds, Jack R. Tanner, Aly Artusio-Glimpse, Paul A. Williams, Niranjan Parab, Cang Zhao, Tao Sun
During laser powder bed fusion additive manufacturing, a protean pool of molten metal governs a complex energy absorption process as it presents as either a highly reflective surface, a deeply absorbing cavity (a keyhole), or some amalgamation thereof. To

In Situ Monitoring of Cu/Al Laser Welding using Laser Induced Fluorescence

September 10, 2020
Author(s)
Brian Simonds, Tran N. Tran, Paul A. Williams
We investigate laser spot welding of 200 µm thick Cu and Al foils using laser-induced fluorescence (LIF). The key to strong Cu/Al welds is limited intermetallic compound formation through controlled molten metal interaction time. For laser lap welds, Cu in

Simultaneous High-speed X-ray Transmission Imaging and Absolute Dynamic Absorptance Measurements during High-power Laser-metal Processing

September 10, 2020
Author(s)
Brian Simonds, Jack R. Tanner, Alexandra B. Artusio-Glimpse, Paul A. Williams, Niranjan Parab, Cang Zhao, Tao Sun
During high-power laser metal processing, the absorbed light is intimately related to the molten metal cavity shape. For the first time, we directly and simultaneously observe this relationship by implementing state-of-the-art techniques of high-speed x

Measurement of thermophysical properties of NIST SRM 1155a (Cr18-Ni12-Mo2)

December 9, 2019
Author(s)
Peter Pichler, Brian Simonds, Jeffrey W. Sowards, Gernot Pottlacher
SRM 1155a is an AISI 316 stainless steel (Cr18-Ni12-Mo2) and Standard Reference Material (SRM) intended for use with test methods for elemental analysis. At the National Institute of Standards and Technology (NIST) in Boulder, Colorado dynamic absorptance

Time-Resolved Absorptance and Melt Pool Dynamics during Intense Laser Irradiation of a Metal

October 25, 2018
Author(s)
Brian J. Simonds, Jeffrey W. Sowards, Joshua A. Hadler, Erik A. Pfeif, Boris Wilthan, Jack R. Tanner, Paul A. Williams, John H. Lehman
Laser welding is a complex, dynamic process by which focused, high-intensity laser light is used to join two metallic surfaces and is being increasing deployed in a variety of industrial applications. Determining the time-dependent absorptance of the laser

Dynamic and absolute measurements of laser coupling efficiency during laser spot welds

September 3, 2018
Author(s)
Brian J. Simonds, Jeffrey W. Sowards, Joshua A. Hadler, Erik A. Pfeif, Boris Wilthan, Jack R. Tanner, Chandler Harris, Paul A. Williams
Laser absorptance (coupling efficiency) changes rapidly during laser metal processing due to temperature and multiple phase changes. We find that there is limited literature data available, but this property is vital for accurate process simulations, as

Reduction of Short Wavelength Reflectance of Multi-wall Vertically Aligned Carbon Nanotubes Through UV Laser Irradiation

May 29, 2018
Author(s)
Michelle S. Stephens, Brian J. Simonds, Christopher S. Yung, Davis R. Conklin, David J. Livigni, Alberto R. Oliva, John H. Lehman
Multi-wall carbon nanotube coatings are used as broadband, low-reflectance absorbers for bolometric applications, blackbody radiators, and for stray light control. Irradiation of single wall carbon nanotubes with UV laser light has been shown to remove

On-site multi-kilowatt laser power meter calibration using radiation pressure

December 1, 2017
Author(s)
Paul A. Williams, Joshua A. Hadler, Brian J. Simonds, John H. Lehman
We have demonstrated the calibration of a thermal power meter against a radiation-pressure power meter in the range of 20 kW in a manufacturing test environment. The results were compared to a traditional calorimeter-based laboratory calibration undertaken

Low-Cycle Fatigue Behavior of Fiber-Laser Welded, Corrosion-Resistant, High-Strength Low Alloy Sheet Steel

February 21, 2017
Author(s)
Jeffrey W. Sowards, Erik A. Pfeif, Matthew J. Connolly, Joseph D. McColskey, Stephanie L. Miller, Brian J. Simonds, James R. Fekete
Incorporation of high-strength steels into ground vehicles provides a weight-savings advantage by using thinner sections of material, which increases vehicle efficiency. Advanced welding techniques such as fiber laser welding are a potential method for

Dual-beam laser thermal processing of silicon photovoltaic materials

March 14, 2016
Author(s)
Brian J. Simonds, Anthony Teal, Tian Zhang, Joshua A. Hadler, Zibo Zhou, Sergey Varlamov, Ivan Perez-Wurfl
Laser processing for photovoltaics (PV) has traditionally been used for very small dimension features where focused beams are rastered to create lines for edge isolation, scribing, and selective emitter formation and for drilling holes for drilling in wrap