Features - March 2017

Alloy Development: Metallurgy Expertise at NETL

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We are a society in flux, constantly adapting to the new technological marvels being created through the ingenuity of scientists across the world. But these technologies are not merely theoretical breakthroughs, they are physical creations—from the smartphone that never leaves your side to the advanced power generation facility that produces the energy that warms your house. Materials development—a field of research dedicated to designing and creating new, more durable materials for use in extreme operating environments—is integral to taking technology from the realm of thought to the marketplace.

At NETL, alloy development is a critical component of our materials development program.
Many technologies incorporate metal components. However, in their base state, most metals are useless in advanced applications—but metals can be altered! An alloy is a mixture of two or more metals in which the atoms of one metal replace, or occupy positions between, the atoms of the other in the crystal structure. Alloys are created to alter the mechanical properties of the base metal, to induce hardness, toughness, ductility, or other desirable properties. This makes alloys essential in a wide variety of fields, from medical devices to a new generation of power plants.

Fossil-fuel power generation relies on materials science to develop components that can withstand extreme environments. The gas turbines of next generation power plants will operate at temperatures over 1000 ⁰C! Continued exposure to high heat and pressure as well as aggressive oxidizing environments can lead to gradual deformation, or creep, wearing the part down over time until it fails. In a gas turbine, for example, creep might cause a turbine blade to warp, reducing the efficiency of the process and requiring the component to be replaced—an expensive proposition. Alloy development is intended to help solve problems like creep by designing metals with specialized physical properties.

But alloy design can be tricky; traditional alloy development methods were arduous and time-consuming, relying on a trial-and-error type approach. NETL now relies on an advanced method of design—computational simulation. The use of supercomputing in alloy design allows scientists to experiment with combining different metals for stronger alloys by running model simulations, instead of physically creating alloys in a laboratory setting and then testing them to gage their effectiveness.

State-of-the-art computer simulations can accurately predict the effects of adding certain elements in specific percentages by weight—using minute adjustments in composition to optimize the efficiency of a material. Further, computational materials modeling and simulation in the design phase save valuable time by allowing researchers to focus only on combinations of elements that have either been proven to work in similar alloy systems or hypothesized to be beneficial.

However, computer simulation is only one part of what makes NETL alloy development truly outstanding. When creating a new heat-resistant alloy, no amount of modeling will lead to success without prototyping the alloy at scales that readily translate to commercial manufacturing and testing alloy performance at service conditions. The alloy development laboratories at NETL include world facilities for prototyping the alloy fabrication and performance testing in realistic service environments that are vital to Fossil Energy’s materials research.

NETL’s unique Liquid Metals Processing laboratory plays a critical role in the development of high performance alloys. NETL’s Vacuum Induction Melt (VIM) furnaces and Vacuum Arc Remelt/ Electro-Slag Remelt (VAR/ESR) furnace, which is capable of melting ingots up to 450 pounds, are utilized by NETL scientists not only to produce new alloys but also to develop improved melt processing techniques to reduce residual impurities and enhance the performance of alloys for mission critical applications. NETL’s thermo-mechanical processing (TMP) facility, allows for ingots to be reduced into plate or sheet materials for further evaluation. NETL’s alloy processing equipment allow for producing new alloys in quantities that translate to industrial practices, and thus, gives confidence that industry will be able to reproduce NETL results.

NETL is well known for its expertise in metallurgy—a reputation that has been earned through the laboratory’s cutting edge facilities, innovative advancements in research processes, ingenuity of the scientists and engineers that run the programs, and, ultimately, the advanced products that the laboratory produces. The alloy development program at NETL is one of the best in the world and the research it conducts—from power generation technologies to medical breakthroughs—has benefitted the American people for decades, and will continue to long into the future.