Designing Metals

by Bob Gariano

The Hittites of Asia Minor perfected the smelting of iron 3500 years ago. The new material provided a military advantage that allowed them to rule over an empire that rivaled the Egyptians for 1000 years. Even though early iron was not as hard as bronze, it can be hammered and worked with heat to produce a variety of shapes. The Hittites considered iron to be more precious than silver and, when discovered that it fell to earth in meteorites, they were certain that it had magical properties bequeathed directly from heavenly sources.

Iron's utility was enhanced when Andrew Carnegie brought modern steel making technology to the United States in the late nineteenth century. Steel became as fundamental to the industrial revolution as semiconductors are to the information age. Inexpensive high strength steel allowed the design of sky scrapers, metal bridges, automobiles, and railroads. As a network, railroads and modern highways changed human connectivity with an impact that rivals contemporary internet and wireless communications.

North Shore resident, Dr. Greg Olson, is a professor of materials science at Northwestern University's McCormick School of Engineering. He is a world recognized pioneer in the field of computational design of new materials, especially iron based metals and alloys used for the most demanding applications. The company that he co-founded, Ques Tek Innovations LLC, is based in Evanston and develops new materials for companies that need ferrous metals that reach high levels of performance.

"I knew that I wanted to be a scientist when I was in third grade. I was always collecting rocks and minerals. I especially liked crystals." The crystal that particularly attracted Dr. Olson in his later research and commercial career was iron.  Olson was at the Massachusetts Institute of Technology for 23 years earning his undergraduate and graduate degrees and then doing research on metals. In 1988 he came to Northwestern where he is co-director of the University's Material Research Center and director of the Steel Research Group.

Iron, with its various alloys and grain configurations, combines the most attractive properties and economics of any modern material. Iron can be alloyed, heat treated, and formed in a wide variety procedures that alters the molecular and granular structure. These alterations involve thousands of different alloys and an almost limitless configuration of the larger metal crystals or grain structures. The complexity of these different forms results in both the utility and the challenge of iron and steel technology. Over the last three millennia, metallurgists have discovered different formulations purely through experimentation. Dr. Olson's research has changed this approach to developing new materials.

"Computational design means that we can create new materials on the computer instead of in a lab or foundry. We use our chemical and thermodynamic knowledge to predict the performance of new metals before we go into the lab to make samples." It is an approach with substantial advantage in materials that are alloyed and homogenized at 5000 degrees Fahrenheit and which are heat treated at more than 1000 degrees Fahrenheit.

Olson went on, "We still take our new materials into the laboratory to confirm our predictions through testing and analysis. But using an iterative design approach on the computer first means that we can use the information in our data bases to model new metals without the expensive and time consuming process of physical experimentation."

The market implications are distinct. "In space craft, a pound saved is worth $10,000, in aircraft design a pound is worth about $100, and in automobiles a pound is worth $3 or $4. That is why steel technology is so important to automotive manufacturers. Even though the performance of materials like titanium would be useful to automotive companies, its use is limited by its $40 per pound price tag." Computationally designed metals can be the economic answer, providing high performance alloys that meet the market need for performance at lower cost. Olson's company, Ques Tek, is the world leader in developing and licensing such new high performance materials.

Computational material design technology is being proliferated at Northwestern to a new generation of scientists and engineers. "We have a masters program at Northwestern for students who want advanced training in integrated computational materials design. We also have a program for freshman engineers called Murphy Scholars. It teams our most talented freshmen with graduate students to develop expertise in these new techniques."

Dr. Olson is an unusual combination of businessman, scientist, teacher, and engineer. In examining the bare chassis of a new McLaren sports car, he noted, "Using adhesives to bond high strength metal structures has an advantage. You don't have to compromise the alloy by making it suitable for welding. That's how they have been making aircraft for twenty years, so we know it has the properties for other high performance applications like race cars."

He stopped to examine the McLaren's exhaust manifold. "You know the bird cage Maserati of the early 1960s was the first car to use a welded space frame. It was designed for competition at the 24 hours LeMans race. But it failed because the welds on the exhaust manifold tubing kept cracking. Chassis vibration and flexing caused the failures. Today we could help them by designing an alloy to prevent the failures."

Computational design is a modern technology that is changing the way that scientists and engineers design new metals for demanding applications. Integrating computer technology with the most modern testing and analysis procedures provides metals that make high performance products possible.