John W. Cahn - Biography

Biography

Cahn received a bachelor's degree in Chemistry in 1949 from the University of Michigan. He later earned a Ph.D in Physical Chemistry in 1953 from the University of California at Berkeley. His doctoral Thesis was titled "The Oxidation of Isotopically Labelled Hydrazine" and his thesis advisor was R.E. Powell.

In 1954, Dr. Cahn joined the Chemical Metallurgy research effort at the General Electric laboratory in Schenectady, NY, led by David Turnbull. Turnbull had done pioneering work on the kinetics of nucleation, and there was a focus in the group on understanding the thermodynamics and kinetics of phase transformations in solids.

In 1964, Cahn became a professor in the Department of Metallurgy (now Materials Science) at the Massachusetts Institute of Technology. He left MIT in 1978. In 1969, Cahn began a long professional relationship with his graduate student Francis Larché, whose work focussed on the effect of mechanical stress on the thermodynamics of solids. The Larche–Cahn approach is the cornerstone of the treatment of the thermodynamics of stressed materials. Good examples of this phenomenon are the regions near a coherent precipitate—or the stress field around a dislocation.

In 1972, Cahn worked with David W. Hoffman to formulate a vector-based thermodynamics to describe the thermodynamics of interfaces, a formulation which is necessary to account for anisotropic materials. This is also known as the capillary vector formulation of interface energies. The mathematics of this treatment involves the concept of norms, although Cahn and Hoffman were unaware of it at the time.

In 1975, Cahn worked with his graduate student Sam Allen on phase transitions in Iron alloys, including order-disorder transitions. This work led to the Allen–Cahn equation.

Since 1984, he has held an affiliate professor position at the University of Washington.