Influence of ECAP and Rotary Swaging on Tensile and Fatigue Properties of Grade 4 and Grade 5 Titanium

Superior strength titanium (Ti) alloy rods can be used to produce thinner fasteners and bolts for aerospace applications, resulting in significant weight savings for the aircraft. In order to obtain such superior strength, innovative severe plastic deformation (SPD) and forging methods can be used. In turn, this research investigates the effect of equal channel angular pressing (ECAP) and rotary swaging (RS) on the tensile and fatigue properties of Grade 4 and Grade 5 Ti.

The results suggest that ECAP followed by RS increase yield strength of Grade 4 and Grade 5 Ti by 180 % and 65 %, respectively, while maintaining the ductility above 10 % for both alloys. Moreover, rotating-bending experiments demonstrate a 40 % and 15 % increase in fatigue strength for Grade 4 and Grade 5 Ti, respectively. These results are attributed to a significant reduction in grain size and demonstrate the potential of ECAP and RS as a means for improving mechanical strength of Ti alloys.