Abstract The plastic deformation of the AlSi10Mg alloy manufactured via laser powder bed fusion (LPBF) is incompatible at the microscale, which causes residual strains/stresses and dislocation pile-ups at the Al/Si interfaces and grain boundaries. Hence, it is of fundamental significance to clarify these microscopic properties during plastic deformation. Here, in-situ neutron diffraction is employed to explore the residual strains, stresses, and dislocation density in the LPBF AlSi10Mg during loading-unloading-reloading deformation. It is found that the maximum residual stresses of the Al and Si phases in the loading direction reach up to about −115 (compressive) and 832 (tensile) MPa, respectively. A notable dislocation annihilation phenomenon is observed in the Al matrix: the dislocation density decreases significantly during unloading stages, and the amplitude of this reduction increases after experiencing a larger plastic deformation. At the macroscale, this dislocation annihilation phenomenon is associated with the reverse strain after unloading. At the microscale, the annihilation phenomenon is driven by the compressive residual stress in the Al matrix. Meanwhile, the annihilation of screw dislocations during unloading stages contributes to the reduction in total dislocation density.

中文翻译：

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在加载-卸载-重新加载变形过程中量化增材制造的 AlSi10Mg 中的内部应变、应力和位错密度

摘要 通过激光粉末床熔合（LPBF）制造的 AlSi10Mg 合金的塑性变形在微观尺度上是不相容的，这会导致在 Al/Si 界面和晶界处产生残余应变/应力和位错堆积。因此，阐明塑性变形过程中的这些微观特性具有重要意义。在这里，原位中子衍射被用来探索 LPBF AlSi10Mg 在加载-卸载-重新加载变形过程中的残余应变、应力和位错密度。发现Al和Si相在加载方向的最大残余应力分别达到约-115（压缩）和832（拉伸）MPa。在铝基体中观察到显着的位错湮灭现象：在卸载阶段位错密度显着降低，在经历更大的塑性变形后，这种减少的幅度会增加。在宏观尺度上，这种位错湮灭现象与卸载后的反向应变有关。在微观尺度上，湮灭现象是由铝基体中的压缩残余应力驱动的。同时，卸载阶段螺位错的消失有助于总位错密度的降低。