A. Shapiro

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Alan Luo

Ranadip Acharya

Georgia Institute of Technology

Ina Yadroitsava

Central University of Technology

Dierk Raabe

Max Planck Institute for Iron Research

Frank Adjei-Kyeremeh

University Of Mines and Technology, Tarkwa

Jimy Unfried Silgado

UNIVERSIDAD DE CÓRDOBA (MONTERÍA)

R. L. Narayan

Indian Institute of Technology Delhi

Helen Kamoutsi

UNIVERSITY OF THESSALY, GREECE

Charles-Andre Gandin

Mines Paristech

Richard Sisson

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Papers by A. Shapiro

Integration of Processing and Microstructure Models for Non-Equilibrium Solidification in Additive Manufacturing

Metals

Integration of models that capture the complex physics of solidification on the macro and microst... more Integration of models that capture the complex physics of solidification on the macro and microstructural scale with the flexibility to consider multicomponent materials systems is a significant challenge in modeling additive manufacturing processes. This work aims to link process variables, such as energy density, with non-equilibrium solidification by integrating additive manufacturing process simulations with solidification models that consider thermodynamics and diffusion. Temperature histories are generated using a semi-analytic laser powder bed fusion process model and feed into a CALPHAD-based ICME (CALPHAD: Calculation of Phase Diagrams, ICME: Integrated Computational Materials Engineering) framework to model non-equilibrium solidification as a function of both composition and processing parameters. Solidification cracking susceptibility is modeled as a function of composition, cooling rate, and energy density in Al-Cu Alloys and stainless steel 316L (SS316L). Trends in soli...

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Advances in additive manufacturing of metal-based functionally graded materials

International Materials Reviews

Additive manufacturing of a functionally graded material from Ti-6Al-4V to Invar: Experimental characterization and thermodynamic calculations

Acta Materialia, 2017

Amorphous Metals and Composites as Mirrors and Mirror Assemblies

Stress Testing of a Recrystallizing CaO-B 2 O 3 -SiO 2 Glass-Ceramic with Ag Electrodes for High Frequency Electronic Packaging

Journal of Electronic Materials, Apr 1, 2001

CaO-B 2 O 3-SiO 2 recrystallizing glass-ceramics are attractive for use in microelectronics packa... more CaO-B 2 O 3-SiO 2 recrystallizing glass-ceramics are attractive for use in microelectronics packaging since they can be processed at low temperatures (<950°C) and the resultant material has a low loss tangent. This paper reports on the stability of the Ag electrodes with respect to electromigration. Planer multilayer recrystallizing glass-ceramic/Ag samples were prepared and fired at temperatures from 800-950°C. Buried capacitor structures with Ag plates 10 mm in diameter with a separation distance of 0.1 mm were created. These were stressed with voltages from 50V to 3 kV at temperatures from 25°C to 200°C to induce failure. Failure modes observed ranged from increased leakage to catastrophic events. A population was analyzed for mean time to failure characteristics. SEM and EDX were used to try to identify leakage paths and movement of the Ag through the glass ceramic. An activation energy was determined for the most common failure mode.

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Via resistors within-multi-layer, 3 dimensional structures substrates

Via capacitors within multi-layer, 3 dimensional structures/substrates

Magnetic Vias Within a Multilayer Circuit Board

Low temperature co-fired ceramic substrates for power converters

Low temperature co-fired ceramic UHF/VHF power converters

Ferrimagnetic vias within multi-layer 3-dimensional structures/substrates

A comparison of microstrip models to low temperature co-fired ceramic–silver microstrip measurements

Microelectronics Journal, May 1, 2002

A number of analytical and numerical models for microstrip lines are used for analyzing the propa... more A number of analytical and numerical models for microstrip lines are used for analyzing the propagation loss of CaO–B2O3–SiO2-based low temperature co-fired ceramics (LTCC) subjected to different processing conditions. An optimal microstrip model is identified for the frequency range between 0.5 and 15GHz and used for the extraction of dielectric loss for this material system. The measurements show that the

Characterization of Electrical Failure Modes in Chip-on-Board Assemblies for Extreme Temperature Environments

Advances in Electronic Packaging, Parts A, B, and C, 2005

ABSTRACT Future space missions to Mars and the outer planets will have to operate on the planet s... more ABSTRACT Future space missions to Mars and the outer planets will have to operate on the planet surface in temperatures that range from -200 degrees C to 400C. These missions will require sensors, instruments and motors to operate for extended periods that exceed the duration of any planetary surface mission to date. Currently the Mars Science Laboratory rovers planned for 2009 will be required to survive a mission life of about 500 Martian sols. The Martian solar day is called a sol and is equal to 24 hours and 39 minutes of an Earth day. This extended mission requirement is beyond the reliability threshold of present electronic materials and interfaces such as those used on the Mars Exploration Rovers. The combination of correct materials, electrical interconnection and packaging design are critical to ensuring long life when the range between minimum and maximum temperatures approach or exceed 200 degrees C.

Tunable Passive Vibration Suppressor

Low-temperature-cofired-ceramic (LTCC) tape structures including cofired ferromagnetic elements, drop-in components and multi-layer transformer

Low-temperature-cofired-ceramic (LTCC) tape structure including a cofired ferromagnetic element

Planning a Large-Scale Progression of R&D – a Pilot Study in the Aerospace Domain

2006 IEEE Aerospace Conference, 2006

A prior case study reported in "Programmatic Risk Balancing" [D.M. Tralli, IEEE Aerospace Confere... more A prior case study reported in "Programmatic Risk Balancing" [D.M. Tralli, IEEE Aerospace Conference 2003] established the suitability of adopting a lifecycle risk management decision-support tool to the planning of application projects across NASA's Earth Science Enterprise. Here we report on a pilot study to gauge the suitability of this same approach for large-scale planning of a progression of research and development efforts in the Aerospace domain. The purpose of the study was to assess feasibility and utility, and to prototype adaptations to the approach as and when such adaptations were found to be needed.

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The environmental degradation of YBa₂Cu₃Ox̳ thick film superconductor /

ABSTRACT

Biocomplex dimensions of industrial ecology: sectoral trade-offs on selecting alternatives to lead (Pb) in electronics

Engineering and economic considerations are typical driving forces behind the selection of specif... more Engineering and economic considerations are typical driving forces behind the selection of specific chemicals used to manufacture consumer products. Only recently have post-consumer environmental impacts become part of the considerations during the initial phases of sustainable product design. Therefore, reactive rather than proactive strategies have dominated the consideration of environmental and health issues in this context. This study draws from case histories of Pb use in industrial sectors to produce guidelines for modeling possible outcomes of international initiatives to phase out Pb from electronics products where it is primarily used in solder alloys. Data are scarce on the fate and hazards associated with Pb in discarded products such as cell phones and computers, but the environmental health effects of Pb are well documented. Less is known about the fate and effects of proposed alternatives such as silver and bismuth alloys, but industrial convergence to Pb phase-out is deemed inevitable. Avoidance of hazardous alternatives requires quantitative assessment of trade-offs among product reliability, recycling potential, economic costs, public health, and environmental quality. Potential trade-offs are identified to avoid the loop holes that have plagued similar international initiatives to phase out Pb from other industrial processes under conditions of scientific uncertainty about alternative metals.

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