David Turnbull (materials scientist)
Encyclopedia
David Turnbull was an American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 physical chemist who worked in the interdisciplinary fields of materials science and applied physics. Turnbull made seminal contribution to solidification theory and glass formation. Turnbull was born in Elmira, Elmira Township
Elmira Township, Stark County, Illinois
Elmira Township is located in Stark County, Illinois. The population was 391 at the 2000 census.- External links :***...

, Stark County
Stark County, Illinois
Stark County is a county located in the U.S. state of Illinois. According to the 2010 census, it has a population of 5,994, which is a decrease of 5.3% from 6,332 in 2000...

, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

. He graduated from high school in 1932 and then attended Monmouth College
Monmouth College
Monmouth College is a four-year coeducational private liberal arts college located in Monmouth, Illinois, United States.-History:Monmouth College was founded on April 18, 1853 by the Second Presbytery of Illinois, a frontier arm of the Associate Reformed Presbyterian Church...

, specializing in physical chemistry
Physical chemistry
Physical chemistry is the study of macroscopic, atomic, subatomic, and particulate phenomena in chemical systems in terms of physical laws and concepts...

. He received his Ph.D. in physical chemistry under T. E. Phipps from the University of Illinois in 1939. He was on the faculty of Case Institute of Technology from 1939 to 1946.

In 1946, he joined the General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

 research laboratory, performing research into nucleation
Nucleation
Nucleation is the extremely localized budding of a distinct thermodynamic phase. Some examples of phases that may form by way of nucleation in liquids are gaseous bubbles, crystals or glassy regions. Creation of liquid droplets in saturated vapor is also characterized by nucleation...

 of structural transformations occurring during the solidification of liquid metals, demonstrating that such complex processes could be quantitatively understood. Using a low-melting-point metal, gallium
Gallium
Gallium is a chemical element that has the symbol Ga and atomic number 31. Elemental gallium does not occur in nature, but as the gallium salt in trace amounts in bauxite and zinc ores. A soft silvery metallic poor metal, elemental gallium is a brittle solid at low temperatures. As it liquefies...

, Turnbull determined that the small supercooling
Supercooling
Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid or a gas below its freezing point without it becoming a solid....

s usually seen were the result of heterogeneous catalysts in the melt. When liquid gallium is dispersed as small droplets, large supercoolings could be achieved. The previously empirical study of metal solidification was provided a consistent scientific foundation.

Turnbull and his General Electric colleagues developed metal alloy processing. Turner and I. S. Servi developed homogeneous nucleation theory for a solid-solid transformation, providing the technologically important basis for strengthening metallic alloys through precipitation hardening. With Morrel Cohen, he developed the free volume theory for fluid flow. In 1950, Turnbull formulated a criterion for the ease of glass formation from supeercooled melts with a high viscosity by rapid solidification. Independently and simultaneously to Cohen, he predicted the formation of metallic glass
Amorphous metal
An amorphous metal is a metallic material with a disordered atomic-scale structure. In contrast to most metals, which are crystalline and therefore have a highly ordered arrangement of atoms, amorphous alloys are non-crystalline...

 phases from sufficiently fast cooling of an alloy melt with a deep eutectic. This was demonstrated by Pol Duwez
Pol Duwez
Pol Duwez was a Belgian-born materials scientist. While working at Caltech, he first introduced metallic glasses made through rapid liquid cooling....

 at Caltech in 1959, who produced thin micron-sized sheets of an Au-Si alloy using a very high cooling rate (approximately 106 K/s). H. S. Chen showed in 1971 that mm-sized glassy rods (so-called "bulk metallic glass," or BMG) of Pd-Cu-Si could be produced by suction casting with a cooling rate of 1000 K/s. In 1982, Turnbull then demonstrated that a bulk metallic glass could be produced in the Pd-Ni-P system with a cooling rate as low as 100 K/s.

In 1962, Turnbull joined Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...

 as the Gordon McKay Professor of applied physics
Applied physics
Applied physics is a general term for physics which is intended for a particular technological or practical use.It is usually considered as a bridge or a connection between "pure" physics and engineering....

, where he taught for 23 years. One of his graduate students at Harvard described him as follows: "As a physicist, manager, psychologist and philosopher, he combines the erudition of a Renaissance scholar with the expert knowledge of a 20th century man of Science." He was elected to the National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...

 in 1968, and was awarded the Japan Prize
Japan Prize
is awarded to people from all parts of the world whose "original and outstanding achievements in science and technology are recognized as having advanced the frontiers of knowledge and served the cause of peace and prosperity for mankind."- Explanation :...

 in 1986 "for pioneering contributions to material science". He received the Franklin Medal
Franklin Medal
The Franklin Medal was a science and engineering award presented by the Franklin Institute, of Philadelphia, PA, USA.-Laureates:*1915 - Thomas Alva Edison *1915 - Heike Kamerlingh Onnes *1916 - John J...

 in 1990.

David Turnbull died on April 28, 2007, at the age of 92, in his house in Cambridge
Cambridge, Massachusetts
Cambridge is a city in Middlesex County, Massachusetts, United States, in the Greater Boston area. It was named in honor of the University of Cambridge in England, an important center of the Puritan theology embraced by the town's founders. Cambridge is home to two of the world's most prominent...

, Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...

.
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