Simulation of residual stress and fatigue test in hole extrusion process for Ti 2 AlNb alloy

In order to study the effect of hole extrusion strengthening process on the fatigue performance of Ti2AlNb alloy, a simulation analysis model of residual stress of hole strengthening process was established. The distribution law of surface residual stress and strengthening mechanism after hole extrusion process were discussed. In this work, the hole extrusion experiments were carried out. The high temperature and low cycle fatigue performance of the compressed and un-compressed specimens were tested respectively. Meanwhile, the microstructure characteristics of the fatigue fracture of the two specimens were compared. The results show that the hole extrusion process can produce a strong residual compressive stress layer around the small hole, which effectively delays and inhibits the initiation and propagation of fatigue cracks, and significantly improves the high temperature and low cycle fatigue performance of Ti2AlNb specimens.