The utilization of additive manufacturing (AM) to fabricate robust structural components relies on understanding the nature of internal anomalies or discontinuities, which can compromise the structural integrity. While some discontinuities in AM microstructures stem from similar mechanisms as observed in more traditional processes such as casting, others are unique to the AM process. Discontinuities in AM are challenging to detect, due to their submicron size and orientation dependency. Toward the goal of improving structural integrity, minimizing discontinuities in an AM build requires an understanding of the mechanisms of formation to mitigate their occurrence. This study utilizes various techniques to evaluate the shape, size, nature and distribution of discontinuities in AM Inconel 718, in a non-hot isostatic pressed (HIPed) as-built, non-HIPed and direct age, and HIPed with two step age samples. Non-destructive synchrotron radiation refraction and transmission radiography (SXRR) provides additional information beyond that obtained with destructive optical microscopy. SXRR was able to distinguish between voids, cracks and lack of melt in, due to its sensitivity to the orientation of the discontinuity.

利用增材制造（AM）来制造坚固的结构部件取决于对内部异常或不连续性的了解，这会损害结构完整性。虽然AM微结构中的某些不连续性源于在更传统的工艺（例如铸造）中观察到的相似机理，但其他不连续性是AM工艺所独有的。AM的不连续性由于其亚微米尺寸和方向依赖性而难以检测。为了达到改善结构完整性的目标，要使AM构造中的不连续性最小化，需要了解减轻其发生的形成机理。这项研究利用各种技术来评估AM Inconel 718在非热等静压（HIPed）建造中的不连续形状，大小，性质和分布，非HIP和直接年龄，以及带有两个年龄段样本的HIP。非破坏性同步加速器辐射折射和透射射线照相（SXRR）提供了除破坏性光学显微镜之外的其他信息。由于对不连续方向的敏感性，SXRR能够区分空隙，裂缝和缺乏熔合。