The anisotropic of microstructure for additively manufactured Al alloys is attributed to sharp temperature gradient during laser melting, resulting in anisotropy of mechanical properties. The correlation of grain orientation, size and aspect ratio on mechanical properties were investigated using in-situ EBSD tensile method on selective laser melting Al–Mn-Sc alloys in longitudinal section and cross section. The lattice rotation behavior and the effects of grain orientation, grain size and aspect ratio on mechanical anisotropy were explored. The predominant <001> orientation of the columnar crystals in the longitudinal section and the <102 > and <101> orientation that dominates the equiaxed crystals in the cross-section had a certain influence on the anisotropy of mechanical properties. The grains with different shapes and sizes exhibited different rotation behavior, and lattice rotation of equiaxed crystals with smaller grain sizes was more complex. By introducing anisotropy coefficients (K_a), the anisotropy sensitivity to grain orientations was revealed. Based on the anisotropy coefficient, grain size and aspect ratio, the mechanical anisotropy in both directions was accurately predicted.

增材制造铝合金的微观结构各向异性归因于激光熔化过程中急剧的温度梯度，导致机械性能的各向异性。采用原位 EBSD 拉伸法对选区激光熔炼 Al-Mn-Sc 合金的纵截面和横截面进行了晶粒取向、尺寸和纵横比与力学性能的相关性研究。研究了晶格旋转行为以及晶粒取向、晶粒尺寸和纵横比对机械各向异性的影响。柱状晶在纵向截面中占优势的<001>取向和在截面中占主导地位的等轴晶的<102>和<101>取向对力学性能的各向异性有一定的影响。不同形状和尺寸的晶粒表现出不同的旋转行为，晶粒尺寸较小的等轴晶体的晶格旋转更复杂。通过引入各向异性系数（K_a )，揭示了对晶粒取向的各向异性敏感性。根据各向异性系数、晶粒尺寸和纵横比，准确预测了两个方向的机械各向异性。