Abstract
An apparatus to measure fracture toughness at cryogenic temperatures was made, and elastic-plastic fracture toughness tests were carried out on an aluminum alloy (A5083-0) at 4K and 77K.
The apparatus consists of a testing machine, a cryostat and various measuring systems. The acoustic emission measurement method was applied to detect a critical value of fracture toughness.
There was found good agreement between JIC by the multispecimen method and that by the acoustic emission measurement method at 77K.
Fracture toughness values for the aluminum alloy, were 22kJ/m2 and 20kJ/m2 at 4K and 77K, respectively.
