John W. Cahn
John Werner Cahn ( born January 9, 1928 in Cologne) is an American physical chemist and materials scientist who has been dealing with thermodynamics in materials science.
Life
Cahn's father Felix Cahn was a respected lawyer of Jewish faith in Cologne. In 1933, he fled with his family from the Nazis, first in the Netherlands, where Cahn went to Amsterdam to school. The late 1930s, they fled to the USA and Cahn attended from 1941 to 1945, the Brooklyn Technical High School. In 1945 he became a U.S. citizen.
Cahn studied chemistry at the University of Michigan (Bachelor 1949) and in 1953 received his doctorate at the University of California, Berkeley, Richard E. Powell in Physical Chemistry (The oxidation of isotopically labeled hydrazine). 1952 to 1954 he was instructor at the University of Chicago. After that he went into the research in chemical metallurgy in Metallurgy and Ceramics Research Laboratory, Department of General Electric in Schenectady under David Turnbull. In 1964 he became professor of materials science ( metallurgy at that time ) at the Massachusetts Institute of Technology, where he remained until 1978. After that, he was from 1977 at the National Institute of Standards and Technology (NIST ), where he is a Senior Fellow at NIST Material Science and Engineering Lab since 1984. Since 1984 he has been Professor ( Affiliate Professor ) at the University of Washington. He lives in Seattle.
He was married to Anne Hessing since 1950 and has three children.
Work
Cahn was primarily concerned with thermodynamic description of phase phenomena in liquids and solids. For example, he discussed the separation into two phases with spinodal decomposition, where the phase separation can be described relatively simply ( Cahn- Hilliard equation with John E. Hilliard, 1957 ), since it is a pure diffusion problem, in contrast for example to microbial growth and nucleation ( what Cahn also investigated ) where fluctuations play a role. He dealt with nucleation, crystal growth and dynamics of crystal boundaries in melts. In 1977, he gave a simple thermodynamic formulation of the wetting problem ( wetting ). In the early 1980s he played a major role in the early days of the theory of quasicrystals. In 2002, he was with Leonid Bendersky evidence for the formation of an isotropic glass phase (q- glass) from a molten metal ( iron, aluminum, silicon), with a first order phase transition.
Cahn also dealt with the mathematical theory of phase boundaries and crystal formation, some with Jean Taylor. With his doctoral Francis Larché he developed a thermodynamic theory of solids under tension. With David W. Hoffman in 1972, he developed a vector thermodynamics of interfaces in anisotropic media. With his doctoral Sam Allen, he examined 1975 phase transitions in iron alloys (Allen- Cahn equation)
Honors and Memberships
Cahn is a member of the National Academy of Sciences (1973 ), the American Institute of Metallurgical Engineers, the American Academy of Arts and Sciences and the National Academy of Engineering. 1960/61, he was a Guggenheim Fellow ( and a visiting scholar at the University of Cambridge ). He holds an honorary doctorate from Northwestern University and the Université d' Evry.
Writings
- W. Craig Carter, William C. Johnson (Editor) The selected works of John W. Cahn, TMS ( The Mineral, Metals and Materials Society ), Warrendale, Pennsylvania
- Cahn Adapting thermodynamics to materials science problems, The Hume - Rothery Award Lecture 1993, J. of Phase Equilibria, Volume 15, 1994, pp. 373-379