Improved Low-Cycle-Fatigue Property of Ti-6al-4v Alloy by Adding Trace Fe

Abstract

The low-cycle-fatigue-property properties and cyclic deformation mechanism of Ti-6Al-4V-0.55Fe and Ti-6Al-4V ELI with a duplex microstructure were systematically investigated. With Fe adding, the TC4-F alloy with a better strength and plasticity matching exhibited a longer fatigue life under the selected strain amplitudes. Under low strain amplitude, effect of Fe on dislocation motion, interface resistance, lattice variation, and micro-strain were responsible for the initial lasting cyclic hardening effect and enhanced fatigue life; while under high strain amplitude, Fe brought out the pinning effect on interface. Besides, Fe also limited the fatigue crack propagation.

Keywords: titanium alloy, Low cycle fatigue, Fe element, Micro-strain, Fatigue life