Effect of temperature on the fracture behaviour of heat‐treated Al–Cu–Li alloy laser welds under low‐cycle fatigue loading

The paper presents the results of the studies of the effect of temperature on the fracture behaviour of Al–Cu–Li alloy laser welds under low‐cycle fatigue loading. The mechanical properties and the microstructure of the welded joints without and after postweld heat treatment (PWHT) were investigated. The tensile strength and the low‐cycle fatigue resistance of the welded joints were studied at various test temperatures (20°C, 85°C and − 60°C). It was been found that heating up to 85°C and cooling down to −60°C reduced the maximum number of loading cycles of the welded joints after PWHT by 1.5–2.0 times compared with that at a test temperature of 20°C.