In the early part of the 20th century, most engineering schools had a department of metallurgy and perhaps of ceramics as well. Much effort was expended on consideration of the austenite - martensite - cementite phases found in the iron - carbon phase diagram that underlies steel production.  The fundamental understanding of other materials was not sufficiently advanced for them to be considered as academic subjects. In the post WWII era, the systematic study of polymers advanced particularly rapidly. Rather than create new polymer science departments in engineering schools, administrators and scientists began to conceive of materials science as a new interdisciplinary field in its own right, one that considered all substances of engineering importance from a unified point of view. Northwestern University instituted the first materials science department in 1955.
Richard E. Tressler was an international leader in the development of high temperature materials. He pioneered high temperature fiber testing and use, advanced instrumentation and test methodologies for thermostructural materials, and design and performance verification of ceramics and composites in high temperature aerospace, industrial and energy applications. He was founding director of the Center for Advanced Materials (CAM), which supported many faculty and students from the College of Earth and Mineral Science, the Eberly College of Science, the College of Engineering, the Materials Research Laboratory and the Applied Research Laboratories at Penn State on high temperature materials. His vision for interdisciplinary research played a key role in the creation of the Materials Research Institute. Tressler's contribution to materials science is celebrated with a Penn State lecture named in his honor.
The Materials Research Society (MRS) has been instrumental in creating an identity and cohesion for this young field. MRS was the brainchild of researchers at Penn State University and grew out of discussions initiated by Prof. Rustum Roy in 1970. The first meeting of MRS was held in 1973. As of 2006 , MRS has grown into an international society that sponsors a large number of annual meetings and has over 13,000 members.  MRS sponsors meetings that are subdivided into symposia on a large variety of topics as opposed to the more focused meetings typically sponsored by organizations like the American Physical Society or the IEEE. The fundamentally interdisciplinary nature of MRS meetings has had a strong influence on the direction of science, particularly in the popularity of the study of soft materials, which are in the nexus of biology, chemistry, physics and mechanical and electrical engineering. Because of the existence of integrative textbooks, materials research societies and university chairs in all parts of the world, BA, MA and PhD programs and other indicators of discipline formation, it is fair to call materials science (and engineering) a discipline.