John Cahn, Ph.D., has received the Kyoto Prize for global achievement in the field of advanced technology.
History shows us the vital role that materials play in the progress of human society: our timeline is divided into material “ages,” starting with stone, copper, bronze and iron. The Industrial Revolution was spawned by steel. Today’s Information Age was launched by silicon. The recurring pattern of technology advancing by hitting an old problem with a new material is literally older than recorded history.
A Materials Science Revolution
In the last 50 years, materials science itself has undergone a revolution that is making technological development both more rapid and more exciting in fields ranging from metals and glassy metals to ceramics, crystals and polymers. Until the 1950s, the field of metallurgy was as much a science as a craft, based on principles learned through trial and error—as well as apprenticeship traditions dating back hundreds of years.
The creation of desirable alloys required that molten components be made to flow against their concentration gradients, a demand that appeared to defy the laws of classical thermodynamics yet was known to happen. In the late 19th century, Johannes van der Waals defined conditions under which such movements could occur and referred to them as the “spinod.” Because the components of the still-molten alloy were moving against their concentration gradients, this process became known as “spinodal decomposition.”
In 1951, the first equation was written defining how spinodal decomposition could proceed, given certain concentrations, temperatures and pressures. Despite this important theoretical achievement, it applied only to one dimension and so had no practical application. Later in that decade, John Werner Cahn, Ph.D., and the late John Hilliard, Ph.D., expanded the model to three dimensions, and so brought order to the conditions necessary to create alloys and predictability to how those alloys would form.
Since the mid-1960s, substantial progress in alloy materials, and not just metals, can be traced to Cahn’s theory of spinodal decomposition. Many of the alloys used in modern technology were created with the predictability that spinodal decomposition provides. The Cahn-Hilliard equation has been applied to economics to define the flow of resources and to population dynamics to understand community clusters. It has found widespread application in the design and production of high-performance metals, glass, semiconductors, polymers, heat-resistant materials, and magnets.
By taking trial and error out of the development process, Cahn enabled scientists worldwide to solve the toughest engineering challenges using “designer” materials by calculating the conditions that would lead to the qualities they sought: strength, heat resistance, conductivity, permeability and magnetism. With this development, the art of metallurgy became the science of materials.
Cahn’s research findings have also laid the foundation for the phase-field method, one of the hottest research topics of recent years in the materials sciences. It has proven to be among the most useful additions to the physical and social sciences, but Cahn’s path to these revolutionary theories was an unlikely one, in a career that he describes as being defined by “serendipitous” events.
A Scientist’s Story
John Cahn was born in 1928 in Cologne, Germany. As a young man, his grandfather borrowed a small loan and founded a wine company that grew to become Germany’s largest; as the only male Cahn grandchild, John was destined from a young age to take over the family business as a German wine merchant.
But these were tumultuous times, and thankfully John’s parents had great foresight. His father, an attorney who fought the National Socialist Party and led civil cases against the Nazis in the early 1930s, was met on the way to work one day by a colleague who warned him that Schutzstaffel (SS) officers were awaiting him at his office. In 1933, the Cahns fled their homeland and, at the age of five, John found himself a refugee in Le Coq, Belgium, with other displaced Jews, including Albert Einstein. John would spend the next six years in Holland.
In 1939, he emigrated to America, where he enrolled in public school and was skipped a grade without knowing a word of English. John’s future suddenly looked promising while, tragically, extended family members in Europe became victims of the Holocaust.
Following his graduation from Brooklyn Technical High School (for young men focused on math and science), John enrolled at the University of Michigan. He studied chemistry and tried majoring in mathematics and physics but grew bored. He was dismayed at the idea of a career solving one unexciting problem after another. It was not until his senior year and eventual enrollment in the doctoral program in chemistry at the University of California-Berkeley that John found the excitement and challenge he was looking for in physical chemistry, which was still an evolving field in the mid-1950s. He would find his passion in paradigm-building sciences.
Following a two-year research and instructing position at the University of Chicago’s Institute for the Study of Metals, John spent the next 10 years as a research associate in the Metallurgy and Ceramics Department of the General Electric Co. (GE) Research Laboratory. It was during his research at GE that John began to collaborate with John Hilliard on what would become the basis for their Cahn-Hilliard equation. Published in 1961, the Cahn-Hilliard equation has played a key role in materials science and engineering to explain phenomena as simple as the formation of frost patterns on a car’s windshield and as complex as the clumping of galaxies in the early universe.
Cahn later extended the one-dimensional theory formulated by Mats Hillert, Ph.D., in 1961 to establish his theory of 3-D spinodal decomposition. In addition, he incorporated an elastic strain-energy term, allowing alloy materials to be engineered for highly specific structural and functional characteristics. This theory has since found universal application in the design and production of better-performing metals, glass, semiconductors, polymers, and thermal materials requiring unique properties. Taken as a whole, his work has generated productive lines of research not only in metallurgy but also in physics, mathematics, chemistry, engineering, economics and demography.
The Kyoto Prize
For his contributions, Cahn was awarded the 2011 Kyoto Prize in the category of Advanced Technology. Awarded annually since 1985, the Kyoto Prize was established by Kazuo Inamori, Ph.D., president of the non-profit Inamori Foundation, to honor those who have significantly contributed to humankind’s scientific, cultural, and spiritual betterment. It is Japan’s highest private award for global achievement and includes academic honors, a gold medal, and a cash gift of $625,000. Inamori, an international entrepreneur and humanitarian, established the Kyoto Prize to reflect his belief that there is no higher calling than to work for the greater good of society and to recognize dedicated people who improve the world through their research, science, and art.
As he accepted the award at the Kyoto Prize Ceremony last November, Cahn remarked, “It is…a surprise for someone like me who, almost 60 years ago, began working in the small field of metallurgy, trying to turn an ancient craft into a science. I have been amazed that the results of my research expanded with increasing importance to larger fields.”
Not long after Cahn began his unlikely career that would generate revolutionary theories in materials science, Inamori and his colleagues established Kyocera Corp. As a young entrepreneur, Inamori envisioned a product line based on advanced materials and components, one in which innovation and quality would be at the forefront of development. The advanced ceramics industry owes much to Cahn and his developments in spinodal decomposition and material alloys.
Advanced industrial ceramics are used every day in business and personal communication, in products like computer peripherals and mobile communications, among others. “John’s developments in the theory and models of materials have given scientists tools to understand and make new materials ranging from metals to plastics to ceramics and glass,” said Frank Gayle, Ph.D., chief of Metallurgy at the National Institute of Standards and Technology. “For instance, your smart phone or laptop computer might contain 100 different materials, and John’s work has probably influenced the understanding and development of half of those.”
Researchers worldwide who engage in the development of new materials can celebrate Cahn’s Kyoto Prize—not only as a tribute to a great pioneer, but also as a testament to the value of their own work.
There is great power in mature science.
There are laws and paradigms for everything, and they can be trusted. You know what to measure, how to measure it, and why you need it. With good data, your predictions work and you are almost never wrong. It is very different in the paradigm building sciences, like metallurgy and ceramics. You have to decide what is important, find ways of measuring it, and how to use it. There is usually great collegiality among scientists. You are all hoping to understand the regularities that are observed and trying to formulate laws or paradigms. You are at risk of being wrong. But every once in a while things fall into place, creating great opportunities for further advances.
— John W. Cahn, Ph.D.