ABSTRACT
A knowledge of the properties and behavior of materials used in any cryogenic system is essential for proper design considerations. Often the choice of materials for the construction of cryogenic equipment will be dictated by consideration of mechanical and physical properties such as thermal conductivity (heat transfer along a structural member), thermal expansivity (expansion and contraction during cycling between ambient and low temperatures), and density (weight of the system relative to its volume). Since properties at low temperatures are often significantly different from those at ambient temperature, there is no substitute for test data, and fortunately there are now several excellent data compilations (McClintock and Gibbons, 1960; Durham et al., 1962; Campbell, 1974; Johnson, 1960). To help make sense out of all of the data that do exist, and to help estimate properties when no data are present, it is useful to have certain general rules in mind. Such is the purpose of the following discussion.
