選択式レーザ溶融法により作製した3D積層造形Ti-6Al-4V合金の4点曲げ疲労特性に及ぼすレーザ走査条件の影響

抄録

Additive manufacturing techniques have attracted much attention in various industries due to capability of manufacturing fully functional complex-shaped components by joining material in a layer by layer manner. Fatigue properties of titanium alloy (Ti-6Al-4V) produced via the selective laser melting (SLM) was examined under four-point bending at a stress ratio of 0.1 in the ambient laboratory atmosphere. The fatigue lives of the additively-manufactured Ti-6Al-4V alloy depended on the energy density and laser scanning conditions. Furthermore, the statistical fatigue properties of the additively-manufactured Ti-6Al-4V alloy were analyzed using the Weibull parameters to quantitatively examine the effects of the building conditions on its fatigue life. The shape parameter (Weibull modulus) tended to decrease with increasing the energy density during the SLM method. This result indicates that fatigue life scatter of the additively-manufactured Ti-6Al-4V alloy becomes larger with the energy density at which the SLM was conducted. In this study, the location parameter, which corresponded to the minimum value of N_f, was also estimated by applying the three-parameter Weibull distribution concept. The location parameter of the Ti-6Al-4V alloy additively-manufactured under the laser scanning condition in a uniaxial direction, which was parallel to the short transverse of the specimen, was higher than that of the Ti-6Al-4V alloy produced under the laser scanning condition in multi-axial directions.