Cyclic Plastic Behavior near Crack Tip of Selective Laser Melting 3D Printed Titanium Alloy

The influence of forming direction on the cyclic plastic behavior of crack tip of laser selective melting 3D printed titanium alloy is analyzed by finite element analysis in this article. The results show that ratchet deformation will occur near the crack tip during cyclic loading due to the continuous accumulation of plastic strain. The plastic strain at the crack tip in L3 direction is the largest while the plastic strain in L1 direction is the smallest. The forming direction has only a slight influence on the stress at different positions from the crack tip and local stress ratio. Butterfly-shaped plastic zone can be observed, and the size of monotonic plastic zone is much larger than that of cyclic plastic zone. The increase of molding direction angle will lead to the increase of plastic zone size. This study provides a reasonable theoretical basis for the design of fatigue and fracture of additively manufactured components.