Electron beam welding behavior of a 5083-H15 alloy containing Zr and Sc

Abstract

This study discusses the effects of the addition of Sc and Zr on the microstructure, and mechanical and corrosion properties of an electron beam welded 5083-H15 alloy. The results show that the addition of Sc and Zr to a 5083 alloy exerted a remarkable effect on grain refinement resulting in an enhancement of the mechanical properties. Moreover, the addition of Sc and Zr prompted precipitation of Al3 (Sc, Zr) precipitate in the heat-affected zone during the electron beam welding, thereby hindering the movement of dislocations and inhibiting recrystallization, effectively improving the tensile strength, joint efficiency, and hardness of the welded joint. Combined additions of Sc and Zr to a 5083 alloy led to a remarkable enhancement in the resistance to intergranular corrosion at the weld joints as determined via nitric acid mass loss tests for a reduction from 9.72 to 3.61 mg/cm2. The main reason for the improvement in corrosion resistance is the addition of Sc and Zr. Recrystallization at the welded joint was inhibited by the formation of the Al3 (Sc, Zr) phase during the electron beam welding which acted to suppress the formation of the β phase along the grain boundaries in the welded zone.