Evaluation of mechanical properties of structural materials at cryogenic temperatures and international standardization for those methods

Abstract

Testing methods for mechanical properties of structural materials at cryogenic temperatures had been developed rapidly after 1980, however, until 1985 many researches on cryogenic structural materials have been reported using their own methods and new materials have been developed for ITER. Since 1986, a series of international inter-laboratory comparisons on the evaluation of mechanical properties of cryogenic structural materials have been performed among the participants of US-Japan cooperation project and VAMAS (the Versailles Project on Advanced Materials and Standards) in order to establish unified test methods. Through these international collaborations and Round-Robin Tests, we have accumulated knowledge about mechanical tests at 4 K, and have prepared a draft of an international standard for tensile testing in liquid helium. After testing conditions, strain measurements and other technical points have been discussed, those drafts were submitted to ISO. The outline, development, and discussion of the documents so far, with the results of RRTs, were discussed.