A5048215708- Additive Manufacturing Materials and Processes
- Welding Techniques and Residual Stresses
- Additive Manufacturing and 3D Printing Technologies
- Manufacturing Process and Optimization
- High Entropy Alloys Studies
- Titanium Alloys Microstructure and Properties
- Laser Material Processing Techniques
- Real-time simulation and control systems
- Software Testing and Debugging Techniques
- Advanced Malware Detection Techniques
- Energy Efficiency and Management
- Nuclear Materials and Properties
- Advanced Sensor Technologies Research
- Energetic Materials and Combustion
- Chemical Thermodynamics and Molecular Structure
- Engineering Technology and Methodologies
- Spectroscopy and Laser Applications
- Combustion and Detonation Processes
- Thermal and Kinetic Analysis
Lawrence Livermore National Laboratory
2018-2022
Kairos (United States)
2022
University of California, Berkeley
2014-2016
Tungsten is receiving increasing interest as a plasma facing material in the ITER fusion reactor, collimators, and other structural, high temperature applications. Concurrently, there demand for manufacturing techniques capable of processing tungsten into desired geometries. Additive promising technique able to produce complex parts, but structural integrity compromised by microcracking. This work combines thermomechanical simulations with situ high-speed video microcracking single...
A significant percentage of materials used in industry start particulate form. In many modern applications, these systems undergo processing which necessitate a multiphysical analysis. Several manufacturing applications have arisen that involve the response presence strongly coupled electromagnetic, optical, and thermal fields. The multifield coupling requires methods can capture unique essential physics systems. Specifically, this work, modeling simulation selective laser sintering is...
When tungsten is processed by laser powder bed fusion additive manufacturing, the combination of high residual stresses and tungsten's inherent ductile-to-brittle transition leads to a network microcracks. While preheating widely accepted as most efficient way reduce in additively manufactured parts, thus far it has proven ineffective completely eliminating microcracking tungsten. In addition preheating, changing alloy composition an increasingly popular approach circumvent cracking. This...
Laser powder bed fusion (LPBF) is a powerful tool for additive manufacturing (AM) of metal components. However, fabricating components with overhanging features using LPBF remains challenge. Overhangs suffer from dimensional inaccuracies, high surface roughness, and agglomerated material or dross. These parts often do not meet engineering requirements are discarded reprinted until met, redesigned to avoid overhangs. Printing flat overhang especially challenging due the long, unsupported that...
Metal parts produced by laser powder bed fusion (LPBF) additive manufacturing exhibit characteristic microstructures comparable to those observed in welding. The primary cause of this microstructure is rapid, localized heating and cooling cycles, which result extreme thermal gradients where material solidification followed fast the solid state. final mechanical performance are also influenced pore formation caused melt pool fluid dynamics. Here, we use high speed, situ X-ray diffraction...
Fabricating parts using laser powder bed fusion (LPBF) is of growing interest to many fields, ranging from medical aerospace, but this process often plagued with residual stresses that can reach magnitudes as high the yield strength material. Previous work has demonstrated ability reduce stress during LPBF by over 90% an in situ annealing method makes use large area, shaped light illumination a set diodes. In work, in-depth analysis effectiveness reduction technique presented. A custom...
Laser powder bed fusion has proven to be an effective additive manufacturing technology for the manufacture of complex metal components. However, local thermal history associated with Gaussian beam, raster scan processes produces heterogeneous and spatially non-uniform microstructures that differ from those produced conventional often lack optimized mechanical properties. Steep gradients high cooling rates produce large strains driving residual stress fields can negatively affect dimensional...
Residual stresses in laser powder bed fusion typically reach the yield stress of material, leading to part deformations or even cracking. Previous work showed that there were no measureable residual present tungsten parts, but also these parts riddled with a microcrack network. In this work, strain relaxation due microcracking is directly measured by applying one-dimensional DIC-like techniques high speed videos obtained melting single tracks. Coupled thermomechanical models match release...
Abstract Laser powder bed fusion (L-PBF) is currently the additive manufacturing process with widest industrial use for metal parts. Yet some hurdles persist on way to a widespread serial production, reproducibility of and resulting part properties being major concern. As geometry changes, so do local boundary conditions heat dissipation. Consequently, global, geometry-independent processing parameters, which are today’s state art, may result in varying or even defects. This paper presents...