Fracuture Toughness Test and Application of Acoustic Emission Technich at Cryogenic Temperatures

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 J_IC 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.