Effects of build direction on tensile and fatigue performance of selective laser melting Ti6Al4V titanium alloy

Additive manufacturing Ti6Al4V titanium alloy has a great potential to be applied in aviation structural components. During additive manufacturing process, the deposition layers present because of its intrinsic features, which may affect mechanical properties of additive manufactured parts and components. In order to study the effects of build direction on tensile and fatigue performance of Ti6Al4V manufactured by the selective laser melting technique, three different build direction Ti6Al4V samples (0° sample, 45° sample, 90° sample) were designed and manufactured in this work. Tensile and fatigue tests were performed. Stress versus strain curves, S-N curves and crack growth rate curves were measured and studied. Fracture surfaces were investigated and compared with each other. It is shown that build direction can affect the fatigue performance, but has little effect on fatigue crack growth rate. The tensile and fatigue properties of the 45° sample are the best of the three build directions in this study.