On the Mechanism of Cold Brittleness in Metals

概要

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The results of the present investigation may by summarised as follows : (1) Charpy impact tests were carried out with various forms of notch for Flodin iron, 0.3 and 0.7 per cent carbon steels, zinc and aluminium at temperatures ranging from that of liquid nitrogen up to about 200°. (2) For the purpose of confirming the results, tensile tests were also carried out at low temperatures under various stretching speeds. (3) It is confirmed that the transition temperature from a ductile to a brittle failure is not inherent to a metal as hitherto accepted but is greatly influenced by experimental conditions (4) Considering the time required for slipping one atomic distance caused by the movement of a dislocation at various temperatures, the cold brittleness was interpreted as the phenomenon which appears when the breaking is taken place at the given temperature within this critical time. (5) Some suggestions for the prevention of cold brittleness are remarked. In conclusion the author expresses his cordial thanks to Dr. K. Honda, under whose kind direction the present investigation was carried out, and also to Messrs. S. Yamamura, S. Hongo and H. Yamagata for their enthusiastic help during the course of the work.
東北大学の論文
1949-00-00