Effect of beta flecks on mechanical properties of Ti-10V-2Fe-3Al alloy

The effects of beta flecks on tensile properties and low-cycle fatigue life were investigated at room temperature for Ti-10V-2Fe-3Al alloy. It was found that beta flecks had a significant influence on tensile ductility and low-cycle fatigue life. The greater the volume fraction of beta flecks (P_A) or maximum area of beta flecks (S_max), the lower the tensile ductility and low-cycle fatigue life. Extensive scanning electron microscopy (SEM) and light microscopy (LM) observation showed that under tensile load, cracks preferentially nucleated at β grain boundaries of beta flecks, then grew, connected and propagated along grain boundaries to form characteristics of intergranular fracture and quasi-cleavage fracture. While under an alternating load, beta flecks acted as sites for low-cycle fatigue crack nucleation due to inhomogeneous alternating strains between soft GBα and aged beta matrix. The presence of beta flecks accelerates both the crack nucleation and early crack propagation.