This study is focused on the individual effect of gas porosity size and location on fatigue strength of a laser powder bed fusion Ti6Al4V alloy. Tensile and fatigue samples were manufactured by artificially seeding gas pores either at the centre or close to surface. Seeded porosity reduced the ductility by 20% and fatigue strength by 33% but had little influence on the static strength. Despite seeded pores, 50% fatigue samples had crack initiation from process inherent defects that also caused fatigue data scatter. A modified Kitagawa-Takahashi diagram was established to predict the fatigue strength under the influence of porosity defects.

中文翻译：

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激光粉末床熔化 Ti6Al4V 的缺陷容差和疲劳极限预测

本研究的重点是气体孔隙尺寸和位置对激光粉末床熔融 Ti6Al4V 合金疲劳强度的个体影响。拉伸和疲劳样品是通过在中心或靠近表面的地方人工播种气孔来制造的。种子孔隙率使延展性降低了 20%，疲劳强度降低了 33%，但对静态强度影响不大。尽管存在种子孔，但 50% 的疲劳样品仍因工艺固有缺陷而引发裂纹，这也导致疲劳数据分散。建立了修正的北川-高桥图来预测孔隙缺陷影响下的疲劳强度。