Increased emphasis has been placed on research and development of specialized materials for use in low-temperature applications. Most research has been driven by (1) the construction of large superconducting coils, (2) requirements for transport and storage of liquefied natural gas, and (3) the discovery of superconductors with critical temperatures T c as high as 90 K. The integration between structural design and material properties for critical low-temperature applications has been facilitated by the incorporation of fracture mechanics concepts. This development has led to measurement of an entirely new set of mechanical properties at low temperatures, to increased nondestructive inspection to measure in-situ flaw sizes, and to the development of fracture control practices for a number of cryogenic applications.
IntroductionTo provide focused dissemination of new low-temperature-materials property information, the International Cryogenic Materials Conference (ICMC) was formed in 1974. The conference provided the only means for presenting and discussing the research and development of low-temperature structural metals and alloys and their welds, structural composites, and electrical and thermal insulators, as well as the application of fracture mechanics to inspection, properties, and design for cryogenic structures. And, since it held its meetings in parallel with the Cryogenic Engineering Conference, it provided an opportunity for synergistic interactions between cryogenic engineers and cryogenic materials specialists.For discussion of cryogenic materials research over the past several decades, this paper is divided into two parts, namely overall trends and more significant specific technological advances. In the discussion of overall trends, the papers published in the ICMC proceedings are used to provide quantitative comparisons of variables, such as the origins of the research from various laboratories and worldwide and US trends. The trends of the focus of research (such as on structural alloys, composites, 52
