TB18 titanium alloy is a new type of near-β ultra-high strength titanium alloy

whose high specific strength and high specific stiffness are favored by the aerospace field. Three electron beam welding and heat treatment processes were used to obtain welded joints of TB18 titanium alloy

the relationship between the microstructure and mechanical properties of welded joints are researched through microstructure analysis

tensile and impact property testing

fracture analysis. Results show that TB18 titanium alloy electron beam welded joints consist of the base material

heataffected zone and fusion zone. In three electron beam welding and heat treatment processes

the fusion zone of solid solution+aging + welding state is composed of the softer β phase

resulting in its mechanical properties show lower strength and higher plasticity. The microstructure of the three regions of solid solution + welding + aging state

welding+solid solution + aging state are β-phase precipitated fine dispersed acicular α-phase. But the former in the fusion zone the ratio of length to diameter of acicular α phase is low

resulting in high strength

poor plasticity and brittle fracture. The ratio of length to diameter of welding + solid solution + aging state in three regions is uniform

so its high strength and good plasticity indicate strength and toughness matching characteristics

hence

it is the optimal electron beam welding and heat treatment process scheme.