Deformation and Life of Titanium Alloy VT9 under Conditions of Nonproportional Low-Cycle Loading

Results of experimental investigation of low-cycle fatigue of titanium alloy VT9 under nonproportional loading are presented. Tensile-torsional low-cycle fatigue tests were carried out on thin-walled tubular specimens under proportional and nonproportional cyclic deformation at room temperature. It has been found that cyclic hardening in a steady state at the same value of the equivalent von Mises strain range is the same in circular cycles and in torsion (or tension–compression) cycles. In the case of nonproportional loading of specimens, the life of titanium alloy VT9 shortens in comparison with proportional loading, but not as much as for stainless steels.