Effect of welding speed on the microstructure and mechanical properties of Mo-10Re alloy electron beam welded joints

This study investigated the effects of welding speed on the microstructure and mechanical properties of Mo-10Re alloy electron beam welded (EBW) joints. The weld zone (WZ) was composed of coarse equiaxed grains of a Mo-based solid solution, with oxygen pores concentrated near the fusion line. As welding speed increased from 210 mm/min to 270 mm/min, the following changes were found: the grain size of WZ decreased from 146.1 μm to 110.7 μm; the porosity of WZ increased from 0.23 % to 0.45 %; and the tensile strength of joints increased from 268.2 MPa to 291.3 MPa. All joints failed at the center of the WZ through intergranular fracture, while welding speed had no significant effect on the microhardness of the joints.