Abstract: The mechanical properties of a type of Al-alloy weld including strength, fracture tough-ness and ductility were comprehensively studied at different temperatures. The frac-ture behavior and weld micro features were also characterized. The surface crack test method was adopted to study the fracture toughness and a multiple specimen test ap-paratus was designed to perform the cryogenic experiments. The relationship between the mechanical properties and temperature was obtained together with the fracture toughness distribution in the weld.

Key words: Al-alloy weld, mechanical properties, surface crack, low temperature