Mechanical properties and microstructure of AlMg3 irradiated in SINQ Target-3

An aluminum alloy AlMg3 has been used as the material for safety-hulls of SINQ targets. In the present work, the mechanical properties and microstructure of the material from the beam window of the safety-hull of SINQ Target-3 has been investigated. The tensile test results indicate that both yield stress and ultimate tensile strength increased significantly after irradiation. Meanwhile, for the specimens from the beam centre area irradiated to about 3.6 dpa, their ductility reduced substantially. However, these specimens broke in a ductile fracture mode. TEM observations show that the irradiation induced high-density dislocation loops and helium bubbles. The bubbles locate preferentially at dislocations and grain boundaries. The bubbles at grain boundaries are much larger than those in grain interior. The presence of high-density bubbles may enhance both irradiation hardening and embrittlement effects.