Influence of loading direction on fatigue performance of TC4 titanium alloy laser weld

Comparative experiments have been carried out to analyze the effects of different loading direction on the fatigue performance of TC4 titanium alloy laser weld. The fatigue life and fracture for this two different welding types were compared. The results showed that the straight weld joint's decentrality is smaller than oblique weld. The fatigue life of oblique weld was 1.98 times of the straight weld. The fatigue crack sources of all the welds initiated at the specimens surface in HAZ of straight and oblique welds, where the hardness was the lowest. The crack grew and failed inside the weld showing brittle cleavage for straight weld, while it passed through the weld and fractured at base material for oblique weld, which showed toughness characteristic. The oblique weld had a better toughness feature compared with the straight weld in the final fracture zone.