|Oak Ridge National Laboratory|
Materials by Design
The discovery and development of new and improved materials for clean and efficient commercial vehicles can be accelerated by years by means of the effective use of computational theory to guide the direction of experimental effort. Agreements in this project include efforts to develop more efficient and durable catalysts by means of first-principles modeling of catalyst materials; modeling of the mechanical reliability of engine materials in order to predict the lifetime of engine components under realistic operating conditions, modeling of the mechanical behavior and lifetime of thermoelectric materials for waste heat recovery, and in-situ experiments in a high-resolution STEM to determine the behavior of materials at the nano level.
Milestones: Complete the in-situ microscopy of one or more catalyst systems of current interest, in which Protochips heater and environmental cell capabilities were used for data collection, and submit at least two manuscripts detailing the results for publication in refereed journals (09/09) Complete mechanical database and microstructure characterization of new components designed for the Caterpillar C-15 ACERT diesel engine. (09/09). Generate thermoelastic and mechanical property database as a function of temperature for at least one candidate p- and n-type thermoelectric material fabricated by Marlow Industries. (09/09) A new compositions with improved thermoelectric performance in the temperature range relevant to vehicular waste heat recovery will be predicted and strategies for optimizing materials will be devised. These predictions and their basis in first principles calculations will be described in a technical report prepared in a form suitable for publication. (09/09)Related Agreements:
The advanced sub-Ångström imaging capabilities offered by ORNL’s new aberration-corrected electron microscope (ACEM) will continue to be exploited to provide the highest resolution imaging and spatial resolution energy-loss spectroscopy of catalytic materials in the world. The objective of the proposed research is to continue our new thrust into using in-situ microscopy techniques to study the behavior of monometallic and bimetallic clusters, rafts and nanoparticles on selected oxide support materials, as a result of systematic treatments using special heating and environmental cell holders for the ACEM. The outstanding capabilities of the novel heating technology we are developing in collaboration with Protochips Co. have shown enticing initial results, with changes in morphology of nanocatalysts at sub-Ångström resolution and at temperatures as high as 1000°C being clearly demonstrated. Extension of these results to gaseous reactions using an environmental cell capability will provide information essential for proper design of catalysts that can meet critical regulatory requirements. We will continue to study the mono- and bi-metallic catalyst systems that formed the basis of our studies in FY2008 (e.g. Pt, Au, Pd and alloys of these species on oxide supports such as g-alumina, q-alumina and silica). This work will be continue to be conducted in collaboration with M. Jose-Yacaman, UT-San Antonio; P. Ferreira, UT-Austin; C. Peden, PNNL; and S. A. Bradley, UOP Co. Such information is important for fundamental understanding of how a particular catalytic material works, and will be used in future studies to determine the routes through which the growth and coarsening of particles can be controlled to reduce the degradation of the material.
Milestones: Submit for publication in refereed journals at least two manuscripts detailing the results of in-situ microscopy of one or more catalyst systems of current interest, in which Protochips heater and environmental cell capabilities used for data collection. (09/09)
Contact: Larry Allard, Oak Ridge National Laboratory, 865-574-4981, email@example.com
Objective: The objective of this research agreement, carried out in support of the Cooperative Research and Development Agreement entitled “Materials-enabled High Performance Diesel Engines” between UT-Battelle, Inc. and Caterpillar, Inc., is to characterize the mechanical behavior and durability of new engine components that are designed and implemented for high- performance, high-efficiency heavy duty dieselengines. Results obtained will allow Caterpillar to improve HDD engine efficiency up to 55% by enhancing combustion, and reducing parasitic, frictional, and thermal losses through the utilization of advanced materials technologies. The range of material systems to be evaluated is comprehensive and includes (1) improved structural materials to accommodate higher cylinder pressures and temperatures, (2) improved durability and corrosion resistance, (3) low inertial components to improve transient response, (4) improved emissions aftertreatment performance, and (5) waste heat recovery systems.
Approach: Characterization tasks include the generation of a mechanical engineering database of new materials and components before and after exposure in the Caterpillar ACERT engine installed in a test cell at ORNL; the microstructural evolution and chemical changes during service in these advanced materials; and the application and verification of probabilistic life prediction methods for these new engine components. The results provide key inputs to verify the probabilistic component design and life prediction tasks, which are critical to the successful implementation of advanced diesel engine components.
Milestone: Complete mechanical database and microstructure characterization of new components designed for ACERT diesel engine. (09/09)
Contact: Hua-Tay Lin, Oak Ridge National Laboratory, 865-576-8857, firstname.lastname@example.org
Objective: Measure needed thermomechanical and thermophysical properties of candidate thermoelectric (TE) materials and then use their data with established probabilistic reliability and design models to optimally design automotive and heavy vehicle TE modules. Thermoelectric materials under candidacy for use in TE modules tend to be brittle, weak, and have a high coefficient of thermal expansion (CTE); therefore, they can be quite susceptible to mechanical failure when subjected to operational thermal gradients. A successfully designed TE module will be the result of the combination of temperature-dependent thermoelastic property and strength distribution data and the use of the method of probabilistic design developed for structural ceramics.
Approach: Measure Young’s Modulus, Poisson’s ratio, CTE, thermal conductivity, heat capacity, and strength as a function of temperature of candidate Marlow high-temperature thermoelectric materials. Identify any anisotropic variations. Perform fractography on strength specimens and identify failure initiation sites and strength-limiting flaw types. Critically assess machining strategies of module materials to ultimately maximize their mechanical performance. Use probabilistic design and reliability methods (developed for structural ceramic components) with candidate and
Milestone: Generate thermoelastic and mechanical property database as a function of temperature on at least one candidate p- and n-type material fabricated by Marlow Industries. (09/09)
Objective: We will use modern science-based materials design strategies to find ways to optimize existing thermoelectric materials and to discover new families of high performance thermoelectrics for waste heat recovery applications.
Plan: We will use first principles methods based on quantum mechanics to calculate thermoelectric properties of materials. The calculations will be done using density functional methods to obtain band structures and vibrational properties of existing and notional thermoelectric compounds. We will use these as input for transport calculations, which will be done with Boltzmann theory. These calculations will include the real structural and chemical complexity of materials, and will therefore yield quantitative predictions, both of the thermoelectric properties and their variation with chemical composition. Trends will be identified and used to suggest other compositions to be tested by detailed calculations. The result will be predictions of compositions with improved thermoelectric performance. These will include new thermoelectric materials and modifications of existing materials.
Milestone: A new compositions with improved thermoelectric performance in the temperature range relevant to vehicular waste heat recovery will be predicted and strategies for optimizing materials will be devised. These predictions and their basis in first principles calculations will be described in a technical report prepared in a form suitable for publication. (09/09)
Contact: David Singh, Oak Ridge National Laboratory, 865-241-1944, email@example.com
U.S. Department of Energy • Office of Vehicle Technologies Program