The Charpy Impact Test as an Evaluation of 4 K Fracture Toughness

A 4 K Charpy test is defined as a Charpy test in which the initial temperature of a specimen is 4 K. Two methods, a glass Dewar method and a flow method, are compared in this study to demonstrate that both provide consistent results as long as initial specimen temperature is the same. An improved correlation between the Charpy absorbed energy and the fracture toughness at 4 K is also examined to clarify the limitation of Charpy test applications at cryogenic temperatures.