2004 — 2010 |
Lavernia, Enrique Schoenung, Julie [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
A Fundamental Investigation of the Laser Engineered Net Shaping Process For the Fabrication of Nanostructured Cermets @ University of California-Davis
The research objective of this grant is to investigate the suitability of the Laser Engineered Net Shaping system for the direct net-shape fabrication of nanostructured tungsten-carbide-cobalt cermets and to develop a fundamental understanding of the thermal aspects of the process. This will be accomplished by making nanostructured tungsten-carbide-cobalt cermets in both simple and complex shapes. Physical and mechanical properties of these samples, such as microhardness, yield strength, tensile strength, and modulus of elasticity, will be evaluated. In-situ temperature characterization of the area of the sample affected by the laser beam will be conducted using a two-wavelength imaging pyrometer system, which provides information on the thermal history and the resulting thermal stresses during deposition. X-ray diffraction, in combination with optical microscopy, scanning electron microscopy, transmission electron microscopy and image analysis, will be used to characterize the size distribution, volume fraction and phase decomposition of nanosized tungsten carbide particles in the cobalt matrix, and to establish the relationship between processing variables and particle size, shape and distribution. Different deposition parameters will be used in order to assess the thermal stability of the nanosized tungsten carbide particles and its interaction with the cobalt matrix. Finally, the economic and environmental benefits will be quantitatively assessed, with the use of technical cost modeling and life cycle assessment techniques.
If successful, the benefits of this work will include the ability to fabricate complex shapes with better mechanical properties for products such as tools, dies and nozzles. By using the Laser Engineered Net Shaping system, the need for machining will be minimized, resulting in reduced manufacturing costs, minimized material waste through scrap generation, improved material properties, increased process efficiency, reduced product design time, and reduced environmental contamination. The results of this work will also further the scientific understanding of nanostructured materials and net-shape forming techniques. Furthermore, collaborative activities with industry and national laboratories will be strengthened, and educational programs, including those for underrepresented minorities, will be enhanced.
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0.915 |
2012 — 2016 |
Lavernia, Enrique |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Materials World Network: Nanostructuring and Phase Transformations in Beta-Ti Alloys @ University of California-Davis
Technical Summary: Researchers at the University of California at Davis, USA (UCD) and the Ufa State Aviation Technical University, Ufa, Russia (USATU) will investigate the influence of nanostructuring on the phase transformations and mechanical behavior in beta-Ti alloys. A variety of materials synthesis and processing techniques including mechanical alloying by cryomilling, spark plasma sintering (SPS), equal-channel angular pressing (ECAP) and high pressure torsion (HPT) will be implemented to synthesize nanostructured beta-Ti alloys. Fundamental information generated will be used to establish the relationship between nanostructuring characteristics, thermal stability, phase transformations, and mechanical response in beta-Ti alloys. Microstructure characterization studies using advanced diagnostic techniques (i.e., SEM, TEM), will provide an understanding of the effect of the mechanical alloying, SPS and severe plastic deformation (ECAP/HPT) processing on nanostructural features, and furthermore understanding of fundamental phenomena (e.g., thermal stability, phase transformations and mechanical behavior) associated with nanostructuring in beta-Ti alloys. Mechanical behavior will be studied to establish the relationship between nanostructural features and mechanical response (i.e., elastic modulus, strength, ductility) in nanostructured beta-Ti alloys. Implementation of in-situ SEM and TEM mechanical characterization will provide direct observation of the dynamic deformation and microstructural changes in nanostructured beta-Ti alloys.
Non-Technical Summary: Ti alloys are of scientific and technological interest, and in particular nanostructured beta-Ti alloys may exhibit a high strength with low elastic modulus, which are very attractive for biomedical applications, for example. The collaborative research program will contribute towards the establishment of a fundamental understanding of the science of nanostructured beta-Ti alloys, as well as providing insight into the fundamental relationships that link alloy composition, microstructure and processing history of nanostructured alloys with mechanical behavior. The novel approaches to be implemented, based on complementary expertise and resources between University of California at Davis, USA (UCD) and the Ufa State Aviation Technical University, Ufa, will generate comprehensive information that is currently lacking for understanding of the relationship between nanostructuring, phase transformation and mechanical behavior in beta-Ti alloys and beyond. This, in turn, will ultimately impact the development of Ti materials with potential for applications in the biomedical, aerospace, and automotive industries. The research activities will help nurture intellectual collaborations and academic exchanges through mutual visits, in particular with participation of students at the graduate and undergraduate levels between UCD and USATU. This international collaboration will also enrich UCD's outreach program and will involve regional universities, colleges, and K-12.
The project is supported by the Metals and Metallic Nanostructures program and the Office of Special Programs, Division of Materials Research.
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0.915 |
2014 — 2018 |
Lavernia, Enrique Sachdev, Anil |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Goali: Influence of Length-Scale On Diffusion During Fast (Field-Assisted Sintering Technology) @ University of California-Davis
Titanium and its alloys represent an important family of materials providing energy efficiency along with mechanical and environmental advantages but have seen only limited application primarily due to the high cost of production. Electric field-assisted sintering technology, sometimes called spark plasma sintering, is a novel process for the consolidation of powders or particulates that offers cost advantages over conventional approaches. The team of this Grant Opportunity for Academic Liaison with Industry (GOALI) project will contribute to the fundamental understanding of molecular diffusion behavior during field-assisted sintering for titanium and titanium powders that will enable cost-effective manufacturing of these materials while maintaining material attributes such as high strength, low density and environmental inertness. The findings will impact both the automotive and aerospace industries. The collaborative university-industry research team will educate university students as well as provide outreach activities to attract high school students to engineering careers.
Availability of diffusion data in multicomponent systems has been scarce due to the complexity of diffusion analyses and the dependence of interdiffusion coefficients on composition. This has prevented accurate modeling of the kinetics of sintering for ternary or higher order systems encountered in commercially important materials. The research team will generate ternary interdiffusion coefficients for titanium-aluminum-niobium systems, an important material system for automotive and aerospace applications. In the presence of an electric field during field-assisted sintering, the phase equilibrium can be altered giving rise to new phases or eliminating certain phases during processing. The effects of an imposed electric field and microstructural length scale will be assessed through a set of experiments and simulations that will provide insight into the thermodynamics and kinetics of the interdiffusion and phase equilibria/transformation for the chosen material system. With this insight, titanium alloys can be designed and manufactured with desired properties at lower cost than is available today.
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0.915 |