SBIR-STTR Award

Power transmission as a global industry, whose efficiency has suffered due to growing demands for energy, requires further material development to reduce energy losses and promote further refinement towards the creation of a sustainable energy grid. Materials used for transmitting electricity are directly limited by their electrical conductivity, and indirectly by the combination of its strength and its use in supporting the weight of the cable. Under this SBIR program, QuesTek Innovations LLC, a leader in the field of integrated computational materials engineering (ICME), proposes to design a high conductivity aluminum alloy with greater strengthening efficiency, thermal stability, and thermal softening resistance than incumbent aluminum alloys used in electrical conductor applications. This will lead to improved conductivity of existing commercial composite conductors without a loss in strength. The Phase I program will involve modeling the expected behavior of a high efficiency precipitation strengthened aluminum alloy pursuing conventional processing and manufacturing routes. QuesTek- developed models have been developed to predict targeted material properties for aluminum alloys such as electrical conductivity and strength, as well as thermodynamic information used to design prospective alloys. QuesTek will leverage its experience in computational materials design to strategically identify alloying strategies and processing methods that can provide the desired material properties, and subsequently produce material using processing methods compatible with the manufacturing of the end- product. Once made, specimens in various processing conditions, such as cast, drawn, aged, etc. will be evaluated by conductivity testing, tensile deformation, and microstructural characterization via electron microscopy. Data collected from lab-scale processing operations will inform further model development to link microstructure, strength, and conductivity as a function of thermo-mechanical processing. In Phase II, QuesTek will make a second design iteration based on the results of the Phase I to optimize the combination of composition and thermo-mechanical processing. QuesTek will partner with commercial cable manufacturers to implement the alloy design in a demonstration composite cable component and validate the expected improvement in performance by evaluating cable resistance, breaking strength, and thermal stability of a demonstration cable that would represent the final product transmission cable.

The DOE Conductivity-enhanced materials for Affordable, Breakthrough Leapfrog Electric and thermal applications (CABLE) initiative has brought together the insights of stakeholders in science & engineering, manufacturers, utility companies, and other entities in electrical product supply chains. These insights identified the need for new cost effective, conductivity-enhanced materials which will have a significant impact on the evolving national grid and electricity delivery system (EDS). Specifically, reducing transmission losses will be important for reducing costs to distributors and consumers. New materials will also play a significant role in the integration of renewable energy onto the grid. Recent events, such as the wildfires on the west coast of the United States, have also elucidated the need for increased component performance in extreme environments, where thermal stability, mechanical properties, and corrosion resistance may play a role in the operation and safety of the conductors. Material improvements to the components used for electrical transmission have been identified as a viable approach to implement a breakthrough solution at the fundamental level. These improvements will enable the concurrent design and development of more efficient, safer transmission cables to help meet the needs of the DOE. This thrust of the CABLE initiative also focuses on manufacturing and scale-up of new technologies to ensure that new materials can be fabricated at the lab scale in a way that is predictive of large-scale production. During the Phase I program, QuesTek Innovations, a leader in the field of Integrated Computational Materials Engineering (ICME) and 2016 Tibbetts Award recipient, applied its ICME-based Materials by Design® methodologies and designed three aluminum alloy concepts to achieve higher performance and value effectiveness in overhead electrical transmission applications. These alloy concepts were designed to achieve high electrical conductivity, withstand higher temperatures, improve strength over baseline materials, utilize novel strengthening phases while simultaneously being cost conscious, and demonstrating processibility and achieving target microstructures. During the Phase I program, the QuesTek team identified target property windows in % IACS and hardness and achieved them through alloying and material processing. Aging studies at elevated temperatures demonstrated greater thermal stability than incumbent aluminum alloys used in cables. Processing methods were identified for further investigation which would be conducive to industrial scale-up. Under the proposed Phase II effort, QuesTek will finalize the alloy design of the new aluminum conductor, considering a balance between performance and cost. The alloy will then be scaled-up with respect to material production to address the CABLE initiative thrust to capture at-volume relevant properties in laboratory/pilot scale production environments. QuesTek will develop a dataset relevant to cable applications and compare the new material with incumbent alloys, and work with OEMs to manufacture and test a demonstration component.