Texture-mediated cryogenic tensile anisotropy in LPBF AlSi7Mg fabricated with different scan-rotation strategies

Cryogenic anisotropy in laser powder bed fused (LPBF) AlSi7Mg can affect the structural reliability of lightweight components operating at 77 K. In this work, two interlayer scan-rotation strategies, 67° and 90°, were compared to clarify how rotation-induced texture differences influence deformation heterogeneity under cryogenic tension. Cryogenic tensile testing, quasi in-situ electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM) were employed to correlate initial texture with strain localization, EBSD-derived local misorientation/GND evolution, and dislocation substructures. The 67° strategy retained a stronger <001>//BD fiber texture, whereas the 90° strategy weakened texture intensity and broadened the orientation distribution. These differences were associated with distinct deformation patterns at 77 K: the 67° condition showed more spatially concentrated strain gradients and GND accumulation, while the 90° condition exhibited more distributed strain accommodation and improved hardening sustainability. TEM revealed dense dislocation tangles near cellular boundaries and limited dislocation rearrangement, consistent with suppressed recovery and enhanced dislocation storage at cryogenic temperature. No direct evidence of deformation twinning was observed in the examined α-Al regions. Overall, the results suggest that cryogenic tensile anisotropy in LPBF AlSi7Mg is strongly influenced by the interplay among inherited texture, strain compatibility, and suppressed dynamic recovery, rather than by a change in the fundamentally slip-dominated deformation mode. At 77 K, the yield strength ranged from 300 to 395 MPa and the ultimate tensile strength from 549 to 612 MPa, depending on scan rotation and loading direction.