The deformation behavior of additively manufactured Alloy 718 in as-built condition and after annealing was studied in situ under tensile loading along the build direction. Pre-characterization by synchrotron X-ray diffraction and electron microscopy revealed a significant amount of γ ″ precipitates in the as-built samples, whereas the γ ″ phase was entirely consumed and needle-like δ precipitates appeared in the annealed sample. In situ neutron diffraction (ND) and acoustic emission (AE) enabled indirect observation of the role of the precipitates on the mechanical behavior. ND provided information on the load accommodation in the matrix, while AE detected a strong signal from the interaction of dislocations with the δ -phase precipitates during deformation of the annealed samples. The results imply that in the annealed samples the matrix sheds the load to the precipitates, while in the as-built material the matrix bares a significant load.

中文翻译：

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γ″ 和 δ 相沉淀对选择性激光熔化制造的 Inconel 718 机械性能的影响：原位中子衍射和声发射研究

沿构建方向在拉伸载荷下原位研究了增材制造的 718 合金在建成条件下和退火后的变形行为。通过同步加速器 X 射线衍射和电子显微镜进行的预表征显示，在竣工样品中存在大量 γ ″ 沉淀，而 γ ″ 相被完全消耗，并且在退火样品中出现针状 δ 沉淀。原位中子衍射 (ND) 和声发射 (AE) 能够间接观察沉淀物对机械行为的作用。ND 提供了有关基体中载荷调节的信息，而 AE 检测到来自位错与 δ 相沉淀在退火样品变形过程中相互作用的强信号。